Version July 2025
Because ketoconazole tablets have been associated with serious adverse effects, ketoconazole tablets are not indicated for the treatment of onychomycosis, cutaneous dermatophyte infections, or Candida infections. Use ketoconazole only when other effective antifungal therapy is not available or tolerated and the potential benefits are considered to outweigh the potential risks.
Serious hepatotoxicity, including cases with a fatal outcome or requiring liver transplantation, has occurred with the use of oral ketoconazole. Some patients had no obvious risk factors for liver disease. Inform patients receiving this drug of the risk and closely monitor.
Coadministration of the following drugs with ketoconazole is contraindicated: dofetilide, quinidine, pimozide, lurasidone, cisapride, methadone, disopyramide, dronedarone, and ranolazine. Ketoconazole can cause elevated plasma concentrations of these drugs and may prolong QT intervals, sometimes resulting in life-threatening ventricular dysrhythmias, such as torsades de pointes.
Cushing syndrome (off-label use): Oral: Initial: 400 to 600 mg/day in 2 or 3 divided doses; may increase dose by 200 mg/day every 7 to 28 days up to a maximum of 1.2 g/day in 2 or 3 divided doses. Dosage range: 200 mg to 1.2 g per day; mean effective dose in most studies: 600 to 800 mg/day in 2 divided doses (Ref).
Fungal infection (systemic):
Note: Reserve for when other effective antifungal therapy is not available or tolerated and the potential benefits outweigh the potential risks.
Oral: 200 mg once daily; may increase to 400 mg once daily if response is insufficient. Continue until active fungal infection is resolved; some infections may require a treatment duration of up to 6 months.
Prostate cancer, advanced (off-label use): Oral: 400 mg 3 times daily, in combination with oral hydrocortisone, until disease progression (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
The renal dosing recommendations are based upon the best available evidence and clinical expertise. Senior Editorial Team: Bruce Mueller, PharmD, FCCP, FASN, FNKF; Jason Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC; Michael Heung, MD, MS.
Mild to severe impairment: No dosage adjustment necessary because ketoconazole pharmacokinetics are not significantly altered in patients with kidney impairment (Ref).
Hemodialysis: Minimally dialyzable: No dosage adjustment necessary because ketoconazole pharmacokinetics are not significantly altered in patients on hemodialysis (Ref).
Use is contraindicated in acute or chronic liver disease.
Hepatotoxicity during treatment:
US labeling: If ALT >ULN or 30% above baseline or if patient is symptomatic, interrupt therapy and obtain full hepatic function panel. Upon normalization of liver function, may consider resuming therapy if benefit outweighs risk (hepatotoxicity has been reported on rechallenge).
Canadian labeling: Discontinue therapy for liver function tests >3 times ULN or if abnormalities persist, worsen, or are associated with hepatotoxicity symptoms.
Refer to adult dosing.
(For additional information see "Ketoconazole (systemic): Pediatric drug information")
Fungal infection (systemic): Children ≥2 years and Adolescents: Oral: 3.3 to 6.6 mg/kg/day once daily; maximum daily dose: 400 mg/day; duration of therapy variable based on pathogen, patient, and disease-specific factors. Note: Usual adult dose: 200 mg/day; systemic ketoconazole should only be used when other effective antifungal therapy is not available or tolerated due to potential for serious adverse reactions.
Peripheral precocious puberty (gonadotropin-independent): Very limited data available, optimal dose not defined: Children ≥2 years and Adolescents: Oral: 10 to 20 mg/kg/day in 3 divided doses (Ref). Reported doses in patients with familial male-limited precocious puberty or McCune-Albright syndrome vary widely; however, all describe response with decreased testosterone levels and cessation of puberty; some authors report flat doses of 400 to 600 mg/day divided 2 to 3 times daily (Ref); others describe weight-based doses as high as 30 mg/kg/day in 3 divided doses (Ref).
Cushing syndrome, second-line therapy: Very limited data available: Children ≥12 years and Adolescents: Oral: Initial: 400 to 600 mg/day in 2 or 3 divided doses; doses can be increased by 200 mg/day every 7 to 28 days based on patient response (urinary or plasma cortisol) and tolerability to 800 to 1,200 mg/day in 2 or 3 divided doses (Ref). In one compassionate use trial of adult and pediatric patients with Cushing syndrome (n=108; mean age: 51.3 years; range: 11 to 86 years), median final dose of ketoconazole was 600 mg/day (range: 200 to 1,200 mg/day) in divided doses (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Altered kidney function: Children ≥2 years and Adolescents: Oral:
Mild to severe impairment: No dosage adjustment necessary.
Hemodialysis: Minimally dialyzable: There are no dosage adjustments provided in the manufacturer's labeling; ketoconazole pharmacokinetics are not significantly altered in patients on hemodialysis, and, as a result, no dosage adjustments are necessary (Ref).
Children ≥2 years and Adolescents:
Baseline hepatic impairment: There are no dosage adjustments provided in manufacturer's labeling; use with extreme caution due to risks of hepatotoxicity; use is contraindicated with acute or chronic liver disease.
Hepatotoxicity during treatment: If ALT > ULN or 30% above baseline (or if patient is symptomatic), interrupt therapy and obtain full hepatic function panel. Upon normalization of liver function, may consider resuming therapy if benefit outweighs risk (hepatotoxicity has been reported on rechallenge).
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Frequency not always defined.
Cardiovascular: Orthostatic hypotension, peripheral edema
Central nervous system: Fatigue, insomnia, malaise, nervousness, paresthesia
Dermatologic: Pruritus (2%), alopecia, dermatitis, erythema, erythema multiforme, skin rash, urticaria, xeroderma
Endocrine & metabolic: Hot flash, hyperlipidemia, menstrual disease
Gastrointestinal: Nausea (3%), vomiting (3%), abdominal pain (1%), anorexia, constipation, dysgeusia, dyspepsia, flatulence, increased appetite, tongue discoloration, upper abdominal pain, xerostomia
Hematologic & oncologic: Decreased platelet count
Hepatic: Jaundice
Hypersensitivity: Anaphylactoid reaction
Neuromuscular & skeletal: Myalgia, weakness
Respiratory: Epistaxis
Miscellaneous: Alcohol intolerance
<1%, postmarketing, and/or case reports: Acute generalized exanthematous pustulosis, adrenocortical insufficiency (≥400 mg/day), anaphylactic shock, anaphylaxis, angioedema, arthralgia, azoospermia, bulging fontanel (infants), chills, cholestatic hepatitis, cirrhosis, decreased plasma testosterone (impaired at 800 mg/day), depression, diarrhea, dizziness, drowsiness, erectile dysfunction (doses >200-400 mg/day), fever, gynecomastia, headache, hemolytic anemia, hepatic failure, hepatic necrosis, hepatitis, hepatotoxicity, hypertriglyceridemia, hypersensitivity reaction, impotence, increased intracranial pressure (reversible), leukopenia, myopathy, papilledema, photophobia, prolonged QT interval on ECG, skin photosensitivity, suicidal tendencies, thrombocytopenia
Hypersensitivity to ketoconazole or any component of the formulation; acute or chronic liver disease; coadministration with alprazolam, cisapride, colchicine, disopyramide, dofetilide, dronedarone, eplerenone, ergot alkaloids (eg, dihydroergotamine, ergometrine, ergotamine, methylergometrine), felodipine, irinotecan, lovastatin, lurasidone, methadone, oral midazolam, nisoldipine, pimozide, quinidine, ranolazine, simvastatin, tolvaptan, triazolam.
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Canadian labeling: Additional contraindications (not in US labeling): Women of childbearing potential unless effective forms of contraception are used; coadministration with astemizole or terfenadine.
Concerns related to adverse effects:
• Adrenal suppression: High doses of ketoconazole may depress adrenocortical function; returns to baseline upon discontinuation of therapy. Do not exceed recommended maximum dosing.
• Bone fragility: In animal studies, increased long bone fragility with cases of fracture has been observed with high-dose ketoconazole. Careful dose selection may be advisable for patients susceptible to bone fragility (eg, patients who are postmenopausal, older adults).
• Hypersensitivity reactions: Hypersensitivity reactions, including anaphylaxis and urticaria, have been reported; some reactions occurred after the initial dose.
Disease-related concerns:
• Achlorhydria: Absorption is reduced in patients with achlorhydria.
• CNS infections: Ketoconazole has poor penetration into cerebral-spinal fluid and should not be used to treat fungal meningitis.
• Hepatic impairment: Ketoconazole has been associated with hepatotoxicity, including fatal cases and cases requiring liver transplantation; some patients had no apparent risk factors for hepatic disease. Toxicity was observed after a median duration of therapy of ~4 weeks, but has also been noted after as little as 3 days; may occur when patients receive high doses for short durations or low doses for long durations. Cases have been reported in patients treated with ketoconazole for onychomycosis, cutaneous dermatophyte infections, or Candida infections. Use with caution in patients with preexisting hepatic impairment, those on prolonged therapy and/or taking other hepatotoxic drugs concurrently. Hepatic dysfunction is typically (but not always) reversible upon discontinuation.
• Prostate cancer: In European clinical trials of men with metastatic prostate cancer, fatalities were reported in a small number of study participants within 14 days of initiating high-dose ketoconazole (1,200 mg daily); a causal effect has not been established.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 200 mg
Yes
Tablets (Ketoconazole Oral)
200 mg (per each): $3.16 - $3.79
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 200 mg
Administer oral tablets 2 hours prior to antacids to prevent decreased absorption due to the high pH of gastric contents. Patients with achlorhydria should administer with acidic liquid (eg, soda pop).
Oral: Administer oral tablets 2 hours prior to antacids to prevent decreased absorption due to the high pH of gastric contents. Patients with achlorhydria should administer with acidic liquid (eg, nondiet cola or orange juice).
An FDA-approved patient medication guide, which is available with the product information and at http://www.fda.gov/downloads/Drugs/DrugSafety/UCM362592.pdf, must be dispensed with this medication.
Fungal infections (systemic):
US labeling: Treatment of susceptible systemic fungal infections, including blastomycosis, histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, and chromomycosis in patients who have failed or who are intolerant to other antifungal therapies.
Limitations of use: Ketoconazole should only be used when other effective antifungal therapy is not available or tolerated and the potential benefits outweigh the potential risks. Ketoconazole tablets are not indicated for the treatment of onychomycosis, cutaneous dermatophyte infections, or Candida infections.
Canadian labeling: Treatment of serious or life-threatening systemic fungal infections (eg, systemic candidiasis, chronic mucocutaneous candidiasis, coccidioidomycosis, paracoccidioidomycosis, histoplasmosis, and chromomycosis) where alternate therapy is inappropriate or ineffective; may be considered for severe dermatophytoses unresponsive to other therapy.
Cushing syndrome; Prostate cancer, advanced
Nizoral may be confused with Nasarel, Neoral, Nitrol
Substrate of CYP3A4 (Major); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits CYP2C19 (Weak), CYP2C8 (Weak), CYP3A4 (Strong), P-glycoprotein;
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Abemaciclib: Ketoconazole (Systemic) may increase serum concentration of Abemaciclib. Risk X: Avoid
Acalabrutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Acalabrutinib. Risk X: Avoid
Acrivastine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Acrivastine. Risk C: Monitor
Adagrasib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Adagrasib. Management: Avoid use of adagrasib and strong CYP3A4 inhibitors until adagrasib concentrations have reached steady state (ie, after approximately 8 days of therapy). Risk D: Consider Therapy Modification
Ado-Trastuzumab Emtansine: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Ado-Trastuzumab Emtansine. Specifically, strong CYP3A4 inhibitors may increase concentrations of the cytotoxic DM1 component. Management: Avoid concomitant use of ado-trastuzumab emtansine and strong CYP3A4 inhibitors when possible. Consider alternatives that do not inhibit CYP3A4 or consider administering after CYP3A4 inhibitor discontinuation. Monitor for toxicities if combined. Risk D: Consider Therapy Modification
Afatinib: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Afatinib. Management: If combined, administer the P-gp inhibitor simultaneously with, or after, the dose of afatinib. Monitor closely for signs and symptoms of afatinib toxicity and if the combination is not tolerated, reduce the afatinib dose by 10 mg. Risk D: Consider Therapy Modification
Alcohol (Ethyl): Ketoconazole (Systemic) may increase adverse/toxic effects of Alcohol (Ethyl). Specifically, a disulfiram-like reaction to alcohol may occur. Alcohol (Ethyl) may increase hepatotoxic effects of Ketoconazole (Systemic). Risk X: Avoid
ALfentanil: CYP3A4 Inhibitors (Strong) may increase serum concentration of ALfentanil. Management: If use of alfentanil and strong CYP3A4 inhibitors is necessary, consider dosage reduction of alfentanil until stable drug effects are achieved. Frequently monitor patients for respiratory depression and sedation when these agents are combined. Risk D: Consider Therapy Modification
Alfuzosin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Alfuzosin. Risk X: Avoid
Aliskiren: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Aliskiren. Risk C: Monitor
Alitretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Alitretinoin (Systemic). Management: Consider reducing the alitretinoin dose to 10 mg when used together with strong CYP3A4 inhibitors. Monitor for increased alitretinoin effects/toxicities if combined with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Almotriptan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Almotriptan. Management: Limit initial almotriptan dose to 6.25 mg and maximum dose to 12.5 mg in any 24-period when used with a strong CYP3A4 inhibitor. Avoid concurrent use in patients with impaired hepatic or renal function. Risk D: Consider Therapy Modification
Alosetron: CYP3A4 Inhibitors (Strong) may increase serum concentration of Alosetron. Risk C: Monitor
ALPRAZolam: CYP3A4 Inhibitors (Strong) may increase serum concentration of ALPRAZolam. Risk X: Avoid
Amiodarone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Amiodarone. Management: Consider alternatives to use of amiodarone and strong CYP3A4 inhibitors. If combined, monitor for increased amiodarone concentrations and toxicities. Risk D: Consider Therapy Modification
AmLODIPine: CYP3A4 Inhibitors (Strong) may increase serum concentration of AmLODIPine. Risk C: Monitor
Antacids: May decrease serum concentration of Ketoconazole (Systemic). Management: Administer antacids at least 1 hour prior to, or 2 hours after, ketoconazole. Additionally, administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor patients closely for signs of inadequate clinical response to ketoconazole. Risk D: Consider Therapy Modification
Antihepaciviral Combination Products: May increase serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase serum concentration of Antihepaciviral Combination Products. Specifically, ketoconazole may increase serum concentrations of paritaprevir. Management: Limit the dose of ketoconazole to 200 mg per day in patients taking antihepaciviral combination products. Additionally, monitor for increased ketoconazole effects/toxicities and for increased paritaprevir effects/toxicities. Risk D: Consider Therapy Modification
Apixaban: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Apixaban. Management: US labeling recommends a 50% apixaban dose reduction in patients who would otherwise receive 5 or 10 mg twice daily, and avoiding in patients who would otherwise receive 2.5 mg twice daily. Canadian labeling lists any combined use as contraindicated. Risk D: Consider Therapy Modification
Aprepitant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Aprepitant. Risk X: Avoid
ARIPiprazole Lauroxil: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of ARIPiprazole Lauroxil. Management: Decrease aripiprazole lauroxil dose to next lower strength if used with strong CYP3A4 inhibitors for over 14 days. No dose adjustment needed if using the lowest dose (441 mg). Max dose is 441 mg in CYP2D6 PMs or if also taking strong CYP2D6 inhibitors. Risk D: Consider Therapy Modification
ARIPiprazole: CYP3A4 Inhibitors (Strong) may increase serum concentration of ARIPiprazole. Management: Aripiprazole dose reductions are required for indications other than major depressive disorder. Dose reductions vary based on formulation, initial starting dose, CYP2D6 genotype, and use of CYP2D6 inhibitors. See full interaction monograph for details. Risk D: Consider Therapy Modification
Artemether and Lumefantrine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Artemether and Lumefantrine. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Artemether and Lumefantrine. Specifically, concentrations of dihydroartemisinin (DHA), the active metabolite of artemether may be increased. Risk C: Monitor
Asciminib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Asciminib. Risk C: Monitor
Atazanavir: CYP3A4 Inhibitors (Strong) may increase serum concentration of Atazanavir. Risk C: Monitor
Atogepant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Atogepant. Management: For treatment of episodic migraine, the recommended atogepant dose is 10 mg once daily with a concurrent strong CYP3A4 inhibitor. If used for treatment of chronic migraine, concurrent use of atogepant with strong CYP3A4 inhibitors should be avoided. Risk D: Consider Therapy Modification
Atorvastatin: May increase adverse/toxic effects of Ketoconazole (Systemic). Specifically, there is a theoretical potential for additive effects on reducing endogenous steroid concentrations. Ketoconazole (Systemic) may increase serum concentration of Atorvastatin. Risk C: Monitor
Atovaquone: Ketoconazole (Systemic) may increase serum concentration of Atovaquone. Risk C: Monitor
Avacopan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Avacopan. Management: Decrease the avacopan dose to 30 mg once daily during coadministration with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Avanafil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Avanafil. Risk X: Avoid
Avapritinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Avapritinib. Risk X: Avoid
Axitinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Axitinib. Management: Avoid concurrent use of axitinib with any strong CYP3A inhibitor whenever possible. If a strong CYP3A inhibitor must be used with axitinib, a 50% axitinib dose reduction is recommended. Risk D: Consider Therapy Modification
Barnidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Barnidipine. Risk X: Avoid
Beclomethasone (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Beclomethasone (Systemic). Risk C: Monitor
Bedaquiline: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bedaquiline. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Bedaquiline. Risk C: Monitor
Benidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Benidipine. Risk C: Monitor
Benperidol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Benperidol. Risk C: Monitor
Benzhydrocodone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Benzhydrocodone. Specifically, the concentration of hydrocodone may be increased. Risk C: Monitor
Beta-Acetyldigoxin: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Beta-Acetyldigoxin. Risk C: Monitor
Betamethasone (Nasal): CYP3A4 Inhibitors (Strong) may increase serum concentration of Betamethasone (Nasal). Risk C: Monitor
Betamethasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Betamethasone (Ophthalmic). Risk C: Monitor
Betamethasone (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Betamethasone (Systemic). Risk C: Monitor
Betamethasone (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Betamethasone (Topical). Risk C: Monitor
Bilastine: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Bilastine. Risk X: Avoid
Blonanserin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Blonanserin. Risk X: Avoid
Bortezomib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bortezomib. Risk C: Monitor
Bosentan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bosentan. Risk C: Monitor
Bosutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bosutinib. Risk X: Avoid
Brentuximab Vedotin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Brentuximab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Risk C: Monitor
Brexpiprazole: CYP3A4 Inhibitors (Strong) may increase serum concentration of Brexpiprazole. Management: Reduce brexpiprazole dose 50% with strong CYP3A4 inhibitors; reduce to 25% of usual if used with both a strong CYP3A4 inhibitor and a CYP2D6 inhibitor in patients not being treated for MDD, or strong CYP3A4 inhibitor used in a CYP2D6 poor metabolizer. Risk D: Consider Therapy Modification
Brigatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with strong CYP3A4 inhibitors when possible. If combination cannot be avoided, reduce the brigatinib dose by approximately 50%, rounding to the nearest tablet strength (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). Risk D: Consider Therapy Modification
Bromocriptine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bromocriptine. Management: Consider alternatives to the use of bromocriptine with strong CYP3A4 inhibitors. If combined, monitor closely for increased bromocriptine toxicities and consider bromocriptine dose reductions. Risk D: Consider Therapy Modification
Bromperidol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Bromperidol. Risk C: Monitor
Brotizolam: CYP3A4 Inhibitors (Strong) may increase serum concentration of Brotizolam. Risk C: Monitor
Budesonide (Nasal): CYP3A4 Inhibitors (Strong) may increase serum concentration of Budesonide (Nasal). Risk C: Monitor
Budesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase serum concentration of Budesonide (Oral Inhalation). Management: Consider alternatives to this combination when possible. If combined, monitor for increased corticosteroid adverse effects during coadministration of inhaled budesonide and strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Budesonide (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Budesonide (Systemic). Management: Avoid the concomitant use of CYP3A4 inhibitors and oral budesonide. If patients receive both budesonide and a strong CYP3A4 inhibitor, they should be closely monitored for signs and symptoms of corticosteroid excess. Risk D: Consider Therapy Modification
Budesonide (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Budesonide (Topical). Risk X: Avoid
Buprenorphine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Buprenorphine. Risk C: Monitor
BusPIRone: CYP3A4 Inhibitors (Strong) may increase serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities if combined with strong CYP3A4 inhibitors. Dose adjustments of buspirone or a strong CYP3A4 inhibitor should be based on clinical assessment. Risk D: Consider Therapy Modification
Butorphanol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Butorphanol. Risk C: Monitor
Cabazitaxel: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cabazitaxel. Management: Concurrent use of cabazitaxel with strong inhibitors of CYP3A4 should be avoided when possible. If such a combination must be used, consider a 25% reduction in the cabazitaxel dose. Risk D: Consider Therapy Modification
Cabozantinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cabozantinib. Management: Avoid use of a strong CYP3A4 inhibitor with cabozantinib if possible. If combined, decrease cabozantinib capsules (Cometriq) by 40 mg from previous dose or decrease cabozantinib tablets (Cabometyx) by 20 mg from previous dose. Risk D: Consider Therapy Modification
Calcifediol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Calcifediol. Risk C: Monitor
Calcitriol (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Calcitriol (Systemic). Risk C: Monitor
Cannabidiol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cannabidiol. Risk C: Monitor
Cannabis: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be increased. Risk C: Monitor
Capivasertib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Capivasertib. Management: Avoid concomitant use of capivasertib with strong CYP3A4 inhibitors when possible. If combined, reduce the capivasertib dose to 320 mg twice daily for 4 days, followed by 3 days off. Monitor patients closely for adverse reactions. Risk D: Consider Therapy Modification
Capmatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Capmatinib. Risk C: Monitor
Cariprazine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cariprazine. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Cariprazine. Specifically, concentrations of didesmethylcariprazine (DDCAR), the primary active metabolite of cariprazine, may increase. Management: Cariprazine dose adjustments are recommended and depend upon whether a patient is initiating a strong CYP3A4 inhibitor or cariprazine, as well as cariprazine indication. See full mono for details. Some non-US labels contraindicate this combination. Risk D: Consider Therapy Modification
Celiprolol: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Celiprolol. Risk C: Monitor
Ceritinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ceritinib. Management: Avoid this combination whenever possible. If combined, the ceritinib dose should be reduced by approximately one-third (to the nearest 150 mg). Resume the prior ceritinib dose after cessation of the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
ChlordiazePOXIDE: CYP3A4 Inhibitors (Strong) may increase serum concentration of ChlordiazePOXIDE. Risk C: Monitor
Choline C 11: Antiandrogens may decrease therapeutic effects of Choline C 11. Risk C: Monitor
Ciclesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Ciclesonide (Oral Inhalation). Risk C: Monitor
Cilnidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cilnidipine. Risk C: Monitor
Cilostazol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cilostazol. Management: Decrease the dose of cilostazol to 50 mg twice daily when combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Cinacalcet: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cinacalcet. Risk C: Monitor
Cisapride: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cisapride. Risk X: Avoid
Clarithromycin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Clarithromycin. CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Clarithromycin. Risk C: Monitor
Clindamycin (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Clindamycin (Systemic). Risk C: Monitor
CloBAZam: CYP2C19 Inhibitors (Weak) may increase serum concentration of CloBAZam. CYP2C19 Inhibitors (Weak) may increase active metabolite exposure of CloBAZam. Risk C: Monitor
Clofazimine: May increase serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk C: Monitor
ClonazePAM: CYP3A4 Inhibitors (Strong) may increase serum concentration of ClonazePAM. Risk C: Monitor
CloZAPine: CYP3A4 Inhibitors (Strong) may increase serum concentration of CloZAPine. Risk C: Monitor
Cobicistat: Ketoconazole (Systemic) may increase serum concentration of Cobicistat. Cobicistat may increase serum concentration of Ketoconazole (Systemic). Management: Limit ketoconazole to a maximum adult dose of 200 mg/day in patients being treated with the elvitegravir/cobicistat/emtricitabine/tenofovir combination product. Dosing recommendations for other cobicistat-containing products are not available. Risk D: Consider Therapy Modification
Cobimetinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cobimetinib. Risk X: Avoid
Codeine: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Codeine. Risk C: Monitor
Colchicine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Colchicine. Management: This combination is often contraindicated, but combined use may be permitted with dose adjustment and monitoring. Recommendations vary based on brand, indication, use of P-gp inhibitors, and hepatic/renal function. See interaction monograph for details. Risk D: Consider Therapy Modification
Colchicine: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Colchicine. Colchicine distribution into certain tissues (e.g., brain) may also be increased. Management: This combination is often contraindicated, but combined use may be permitted with dose adjustment and monitoring. Recommendations vary based on brand, indication, use of CYP3A4 inhibitors, and hepatic/renal function. See interaction monograph for details. Risk D: Consider Therapy Modification
Conivaptan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Conivaptan. Risk X: Avoid
Copanlisib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Copanlisib. Management: If concomitant use of copanlisib and strong CYP3A4 inhibitors cannot be avoided, reduce the copanlisib dose to 45 mg. Monitor patients for increased copanlisib effects/toxicities. Risk D: Consider Therapy Modification
Cortisone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cortisone. Risk C: Monitor
Crizotinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Crizotinib. Management: Avoid concomitant use of crizotinib and strong CYP3A4 inhibitors whenever possible. If combined use cannot be avoided, crizotinib dose reductions are required, which vary according to indication. See full interaction monograph for details. Risk D: Consider Therapy Modification
CycloPHOSphamide: Ketoconazole (Systemic) may increase serum concentration of CycloPHOSphamide. Risk C: Monitor
CycloSPORINE (Systemic): Antifungal Agents (Azole Derivatives, Systemic) may increase serum concentration of CycloSPORINE (Systemic). Management: Consider reducing cyclosporine doses by 50% to 80% during coadministration with ketoconazole, 50% with voriconazole or itraconazole, and 25% with posaconazole. Cyclosporine dose reductions may be required with other azoles. Risk D: Consider Therapy Modification
CYP3A4 Inducers (Moderate): May decrease serum concentration of Ketoconazole (Systemic). Risk C: Monitor
CYP3A4 Inducers (Strong): May decrease serum concentration of Ketoconazole (Systemic). Management: The use of ketoconazole concurrently with or within 2 weeks of a strong CYP3A4 inducer is not recommended. If such a combination cannot be avoided, monitor patients closely for evidence of diminished clinical response to ketoconazole. Risk D: Consider Therapy Modification
CYP3A4 Inhibitors (Strong): May increase serum concentration of Ketoconazole (Systemic). Risk C: Monitor
Cyproterone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Cyproterone. Risk C: Monitor
Dabigatran Etexilate: Ketoconazole (Systemic) may increase serum concentration of Dabigatran Etexilate. Management: Dose reductions and/or avoidance of this combination may be necessary. Specific recommendations vary by renal function and indication for dabigatran. Refer to full interaction monograph for details. Risk D: Consider Therapy Modification
Dabrafenib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dabrafenib. Management: Consider alternatives to any strong CYP3A4 inhibitor for patients being treated with dabrafenib. If such a combination cannot be avoided, monitor closely for evidence of dabrafenib-related adverse effects. Risk D: Consider Therapy Modification
Daclatasvir: CYP3A4 Inhibitors (Strong) may increase serum concentration of Daclatasvir. Management: Decrease the daclatasvir dose to 30 mg once daily if combined with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Dapoxetine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dapoxetine. Risk X: Avoid
Daprodustat: CYP2C8 Inhibitors (Weak) may increase serum concentration of Daprodustat. Risk C: Monitor
Daridorexant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Daridorexant. Risk X: Avoid
Darifenacin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Darifenacin. Management: Limit the darifenacin dose to no more than 7.5 mg daily if combined with strong CYP3A4 inhibitors. Monitor patients for increased darifenacin toxicities (eg, dry mouth, constipation, headache, CNS effects) when these agents are combined. Risk D: Consider Therapy Modification
Darolutamide: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Darolutamide. Risk C: Monitor
Darunavir: May increase serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase serum concentration of Darunavir. Management: Limit the adult maximum ketoconazole dose to 200 mg/day in patients receiving darunavir/ritonavir and monitor closely for ketoconazole adverse effects. Risk D: Consider Therapy Modification
Dasatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dasatinib. Management: This combination should be avoided if possible. If combined, decrease dasatinib dose from 140 mg to 40 mg, 100 mg to 20 mg, or 70 mg to 20 mg. For patients taking 60 mg or 40 mg daily, stop dasatinib until the CYP3A4 inhibitor is discontinued. Risk D: Consider Therapy Modification
Deflazacort: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Deflazacort. Management: Administer one third of the recommended deflazacort dose when used together with a strong or moderate CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Delamanid: CYP3A4 Inhibitors (Strong) may increase serum concentration of Delamanid. Management: Increase ECG monitoring frequency if delamanid is combined with strong CYP3A4 inhibitors due to the risk for QTc interval prolongation. Continue frequent ECG assessments throughout full delamanid treatment period. Risk D: Consider Therapy Modification
DexAMETHasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase serum concentration of DexAMETHasone (Ophthalmic). Risk C: Monitor
DexAMETHasone (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of DexAMETHasone (Systemic). Risk C: Monitor
DiazePAM: CYP3A4 Inhibitors (Strong) may increase serum concentration of DiazePAM. Risk C: Monitor
Diazoxide Choline: CYP3A4 Inhibitors (Strong) may increase serum concentration of Diazoxide Choline. Risk C: Monitor
Dichlorphenamide: Antifungal Agents (Azole Derivatives, Systemic) may increase hypokalemic effects of Dichlorphenamide. Risk C: Monitor
Didanosine: May decrease serum concentration of Ketoconazole (Systemic). Management: Administer oral ketoconazole at least 2 hours prior to buffered didanosine. This interaction is not expected with enteric-coated didanosine capsules since they do not contain buffering agents. Risk D: Consider Therapy Modification
Dienogest: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dienogest. Risk C: Monitor
Digitoxin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Digitoxin. Risk C: Monitor
Digitoxin: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Digitoxin. Risk C: Monitor
Digoxin: Ketoconazole (Systemic) may increase serum concentration of Digoxin. Risk C: Monitor
DilTIAZem: CYP3A4 Inhibitors (Strong) may increase serum concentration of DilTIAZem. Risk C: Monitor
Disopyramide: Ketoconazole (Systemic) may increase serum concentration of Disopyramide. Risk X: Avoid
DOCEtaxel: CYP3A4 Inhibitors (Strong) may increase serum concentration of DOCEtaxel. Management: Avoid the concomitant use of docetaxel and strong CYP3A4 inhibitors when possible. If combined use is unavoidable, consider a 50% docetaxel dose reduction and monitor for increased docetaxel toxicities. Risk D: Consider Therapy Modification
Dofetilide: Ketoconazole (Systemic) may increase serum concentration of Dofetilide. Risk X: Avoid
Domperidone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Domperidone. Risk X: Avoid
Doxazosin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Doxazosin. Risk C: Monitor
Doxercalciferol: CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Doxercalciferol. Risk C: Monitor
DOXOrubicin (Conventional): P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of DOXOrubicin (Conventional). Risk X: Avoid
DOXOrubicin (Liposomal): P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of DOXOrubicin (Liposomal). Risk C: Monitor
DroNABinol: CYP3A4 Inhibitors (Strong) may increase serum concentration of DroNABinol. Risk C: Monitor
Dronedarone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dronedarone. Risk X: Avoid
Dutasteride: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dutasteride. Risk C: Monitor
Duvelisib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Duvelisib. Management: Reduce the dose of duvelisib to 15 mg twice a day when used together with a strong CYP3A4 inhibitor. Monitor closely for evidence of altered response to treatment. Risk D: Consider Therapy Modification
Dydrogesterone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Dydrogesterone. Risk C: Monitor
Ebastine: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Ebastine. CYP3A4 Inhibitors (Strong) may increase serum concentration of Ebastine. Risk C: Monitor
Edoxaban: Ketoconazole (Systemic) may increase serum concentration of Edoxaban. Management: In patients treated for DVT/PE, reduce the edoxaban dose to 30 mg daily when combined with oral ketoconazole. No dose adjustment is recommended for patients treated for atrial fibrillation. Monitor for increased edoxaban toxicities (ie, bleeding). Risk D: Consider Therapy Modification
Efavirenz: May decrease serum concentration of Ketoconazole (Systemic). Management: The use of ketoconazole concurrently with or within 2 weeks of efavirenz is not recommended. If such a combination cannot be avoided, monitor patients closely for evidence of diminished clinical response to ketoconazole. Risk D: Consider Therapy Modification
Efonidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Efonidipine. Risk C: Monitor
Elacestrant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Elacestrant. Risk X: Avoid
Elagolix, Estradiol, and Norethindrone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Elagolix, Estradiol, and Norethindrone. Elagolix, Estradiol, and Norethindrone may decrease serum concentration of CYP3A4 Inhibitors (Strong). Specifically, concentrations of strong CYP3A4 inhibitors that are also CYP3A4 substrates may be decreased. Risk X: Avoid
Elagolix: CYP3A4 Inhibitors (Strong) may increase serum concentration of Elagolix. Management: Use of the elagolix 200 mg twice daily dose with a strong CYP3A4 inhibitor for longer than 1 month is not recommended. Limit combined use of the elagolix 150 mg once daily dose with a strong CYP3A4 inhibitor to a maximum of 6 months. Risk D: Consider Therapy Modification
Elbasvir and Grazoprevir: Ketoconazole (Systemic) may increase serum concentration of Elbasvir and Grazoprevir. Risk X: Avoid
Eletriptan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Eletriptan. Risk X: Avoid
Elexacaftor, Tezacaftor, and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase serum concentration of Elexacaftor, Tezacaftor, and Ivacaftor. Management: Administer elexacaftor/tezacaftor/ivacaftor in the morning, twice a week, 3 to 4 days apart, with no evening doses of ivacaftor alone. Specific dosing varies by age and weight. See full monograph for details. Risk D: Consider Therapy Modification
Eliglustat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Eliglustat. Management: Reduce eliglustat dose to 84 mg daily in CYP2D6 EMs when used with strong CYP3A4 inhibitors. Use of strong CYP3A4 inhibitors is contraindicated in CYP2D6 IMs, PMs, or in CYP2D6 EMs who are also taking strong or moderate CYP2D6 inhibitors. Risk D: Consider Therapy Modification
Emedastine (Systemic): Ketoconazole (Systemic) may increase serum concentration of Emedastine (Systemic). Risk C: Monitor
Enasidenib: May decrease serum concentration of Antifungal Agents (Azole Derivatives, Systemic). Risk X: Avoid
Encorafenib: Ketoconazole (Systemic) may increase serum concentration of Encorafenib. Encorafenib may decrease serum concentration of Ketoconazole (Systemic). Management: Avoid use of ketoconazole with encorafenib, and for 2 weeks after encorafenib discontinuation. If combined, decrease encorafenib from 450 mg to 150 mg; or from 300 mg, 225 mg, or 150 mg to 75 mg. Additionally, monitor for reduced ketoconazole efficacy. Risk D: Consider Therapy Modification
Enfortumab Vedotin: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Enfortumab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Risk C: Monitor
Ensartinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ensartinib. Risk X: Avoid
Ensartinib: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Ensartinib. Risk X: Avoid
Entrectinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Entrectinib. Management: Avoid strong CYP3A4 inhibitors if possible. If needed, reduce entrectinib dose to 50 mg on alternating days if starting dose 200 mg; to 50 mg/day if starting dose 300 mg or 400 mg; to 100 mg/day if starting dose 600 mg. Risk D: Consider Therapy Modification
Eplerenone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Eplerenone. Risk X: Avoid
Erdafitinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Erdafitinib. Management: Avoid concomitant use of erdafitinib and strong CYP3A4 inhibitors when possible. If combined, monitor closely for erdafitinib adverse reactions and consider dose modifications accordingly. Risk D: Consider Therapy Modification
Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates): CYP3A4 Inhibitors (Strong) may increase serum concentration of Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates). Risk X: Avoid
Erlotinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Erlotinib. Management: Avoid use of this combination when possible. When the combination must be used, monitor the patient closely for the development of erlotinib-associated adverse reactions, and if such severe reactions occur, reduce the erlotinib dose (in 50 mg decrements). Risk D: Consider Therapy Modification
Erythromycin (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Erythromycin (Systemic). Management: Consider alternatives to this combination when possible. If combined, monitor for increased erythromycin effects and toxicities, including QTc interval prolongation. Risk D: Consider Therapy Modification
Esketamine (Injection): CYP3A4 Inhibitors (Strong) may increase serum concentration of Esketamine (Injection). Risk C: Monitor
Estazolam: Ketoconazole (Systemic) may increase serum concentration of Estazolam. Risk X: Avoid
Estrogen Derivatives: CYP3A4 Inhibitors (Strong) may increase serum concentration of Estrogen Derivatives. Risk C: Monitor
Eszopiclone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Eszopiclone. Management: Limit the eszopiclone dose to 2 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased eszopiclone effects and toxicities (eg, somnolence, drowsiness, CNS depression). Risk D: Consider Therapy Modification
Etizolam: CYP3A4 Inhibitors (Strong) may increase serum concentration of Etizolam. Risk C: Monitor
Etoposide Phosphate: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Etoposide Phosphate. Risk C: Monitor
Etoposide: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Etoposide. Risk C: Monitor
Etravirine: Ketoconazole (Systemic) may increase serum concentration of Etravirine. Etravirine may decrease serum concentration of Ketoconazole (Systemic). Risk C: Monitor
Everolimus: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Everolimus. Risk X: Avoid
Evogliptin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Evogliptin. Risk C: Monitor
Fedratinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Fedratinib. Management: Consider alternatives when possible. If used together, decrease fedratinib dose to 200 mg/day. After the inhibitor is stopped, increase fedratinib to 300 mg/day for the first 2 weeks and then to 400 mg/day as tolerated. Risk D: Consider Therapy Modification
Felodipine: Ketoconazole (Systemic) may increase serum concentration of Felodipine. Risk X: Avoid
FentaNYL: CYP3A4 Inhibitors (Strong) may increase serum concentration of FentaNYL. Management: Consider fentanyl dose reductions when combined with a strong CYP3A4 inhibitor. Monitor for respiratory depression and sedation. Upon discontinuation of a CYP3A4 inhibitor, consider a fentanyl dose increase; monitor for signs and symptoms of withdrawal. Risk D: Consider Therapy Modification
Fesoterodine: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Fesoterodine. Management: Limit fesoterodine doses to 4 mg daily in patients who are also receiving strong CYP3A4 inhibitors. This combination is not recommended in pediatric patients weighing 25 kg up to 35 kg. Risk D: Consider Therapy Modification
Fexinidazole: CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Fexinidazole. Management: Avoid use of fexinidazole and strong CYP3A4 inhibitors when possible. If combined, monitor for reduced fexinidazole efficacy. Risk D: Consider Therapy Modification
Fimasartan: Ketoconazole (Systemic) may increase serum concentration of Fimasartan. Risk C: Monitor
Finerenone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Finerenone. Risk X: Avoid
Fingolimod: Ketoconazole (Systemic) may increase serum concentration of Fingolimod. Ketoconazole (Systemic) may increase active metabolite exposure of Fingolimod. Risk C: Monitor
Flibanserin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Flibanserin. Management: Use of flibanserin with strong CYP3A4 inhibitors is contraindicated. If starting flibanserin, start 2 weeks after the last dose of the CYP3A4 inhibitor. If starting a CYP3A4 inhibitor, start 2 days after the last dose of flibanserin. Risk X: Avoid
Flotufolastat F18: Coadministration of Antiandrogens and Flotufolastat F18 may alter diagnostic results. Management: Therapies targeting the androgen pathway may result in changes in the uptake of flotufolastat F18 in prostate cancer. The impact of these therapies on the performance of flotufolastat F18 is unknown; consider use of alternative agents. Risk D: Consider Therapy Modification
Flunitrazepam: CYP3A4 Inhibitors (Strong) may increase serum concentration of Flunitrazepam. Risk C: Monitor
Fluticasone (Nasal): CYP3A4 Inhibitors (Strong) may increase serum concentration of Fluticasone (Nasal). Risk X: Avoid
Fluticasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase serum concentration of Fluticasone (Oral Inhalation). Management: Consider alternatives to this combination if possible. Coadministration of fluticasone propionate and strong CYP3A4 inhibitors is not recommended. If combined, monitor patients for systemic corticosteroid adverse effects (eg, adrenal suppression). Risk D: Consider Therapy Modification
Fluticasone (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Fluticasone (Topical). Risk C: Monitor
Fosamprenavir: May increase serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase active metabolite exposure of Fosamprenavir. Specifically, amprenavir concentrations may be increased. Management: Limit the adult maximum ketoconazole dose to 200 mg/day with fosamprenavir/ritonavir. In patients receiving fosamprenavir without ritonavir, patients receiving greater than 400 mg/day ketoconazole may also require dose reduction. Risk D: Consider Therapy Modification
Fosaprepitant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Fosaprepitant. Risk X: Avoid
Fostamatinib: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Fostamatinib. Risk C: Monitor
Fusidic Acid (Systemic): May increase serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Consider avoiding this combination if possible. If required, monitor patients closely for increased adverse effects of the CYP3A4 substrate. Risk D: Consider Therapy Modification
Futibatinib: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Futibatinib. Risk X: Avoid
Gallium Ga 68 PSMA-11: Antiandrogens may decrease therapeutic effects of Gallium Ga 68 PSMA-11. Management: Therapies targeting the androgen pathway may result in changes in the uptake of gallium Ga 68 PSMA-11 (gozetotide) in prostate cancer. The impact on the performance of gallium Ga 68 PSMA-11 (gozetotide) is unknown; consider use of alternative agents. Risk D: Consider Therapy Modification
Gefitinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Gefitinib. Risk C: Monitor
Gepirone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Gepirone. Risk X: Avoid
Gepotidacin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Gepotidacin. Management: Avoid coadministration of gepotidacin and strong CYP3A4 inhibitors if possible. If coadministration cannot be avoided, conduct a baseline ECG, monitor closely for altered electrolytes, and correct electrolyte abnormalities as needed. Risk D: Consider Therapy Modification
Gilteritinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Gilteritinib. Management: Consider alternatives to the use of a strong CYP3A4 inhibitor with gilteritinib. If the combination cannot be avoided, monitor more closely for evidence of gilteritinib toxicities. Risk D: Consider Therapy Modification
Glasdegib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Glasdegib. Management: Consider alternatives to this combination when possible. If the combination must be used, monitor closely for evidence of QT interval prolongation and other adverse reactions to glasdegib. Risk D: Consider Therapy Modification
Glecaprevir and Pibrentasvir: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Glecaprevir and Pibrentasvir. Risk C: Monitor
GuanFACINE: CYP3A4 Inhibitors (Strong) may increase serum concentration of GuanFACINE. Management: Reduce the extended-release guanfacine dose 50% when combined with a strong CYP3A4 inhibitor. Monitor for increased guanfacine toxicities when these agents are combined. Risk D: Consider Therapy Modification
Halofantrine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Halofantrine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for halofantrine toxicities, including QTc interval prolongation. Risk D: Consider Therapy Modification
Haloperidol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Haloperidol. Risk C: Monitor
Haloperidol: QT-prolonging Agents (Indeterminate Risk - Caution) may increase QTc-prolonging effects of Haloperidol. Risk C: Monitor
Histamine H2 Receptor Antagonists: May decrease serum concentration of Ketoconazole (Systemic). Management: Administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor for reduced efficacy if concomitant use with a H2RA is required. Increases in ketoconazole dose may be required. Risk D: Consider Therapy Modification
Hormonal Contraceptives: CYP3A4 Inhibitors (Strong) may increase serum concentration of Hormonal Contraceptives. Risk C: Monitor
HYDROcodone: CYP3A4 Inhibitors (Strong) may increase serum concentration of HYDROcodone. Risk C: Monitor
Hydrocortisone (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Hydrocortisone (Systemic). Risk C: Monitor
Hyoscyamine: May decrease serum concentration of Ketoconazole (Systemic). Management: Take hyoscyamine at least 2 hours after ingestion of ketoconazole. Monitor for decreased therapeutic effects of ketoconazole if used together with hyoscyamine. Risk D: Consider Therapy Modification
Ibrexafungerp: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ibrexafungerp. Management: Decrease the ibrexafungerp dose to 150 mg every 12 hours for 2 doses in patients receiving strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Ibrutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ibrutinib. Management: Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for 7 days or less), interrupt ibrutinib therapy until the strong CYP3A4 inhibitor is discontinued. Risk X: Avoid
Idelalisib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Idelalisib. Management: Use alternative therapies that are not strong CYP3A4 inhibitors whenever possible. If unable to use alternative drugs, monitor patients more frequently for idelalisib toxicities. Risk D: Consider Therapy Modification
Ifosfamide: CYP3A4 Inhibitors (Strong) may increase adverse/toxic effects of Ifosfamide. CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Ifosfamide. Risk C: Monitor
Iloperidone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Iloperidone. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Iloperidone. Specifically, concentrations of the metabolites P88 and P95 may be increased. Management: Reduce iloperidone dose by half when administered with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Imatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Imatinib. Risk C: Monitor
Imidafenacin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Imidafenacin. Risk C: Monitor
Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies): May increase hepatotoxic effects of Ketoconazole (Systemic). Risk C: Monitor
Indinavir: Ketoconazole (Systemic) may increase serum concentration of Indinavir. Indinavir may increase serum concentration of Ketoconazole (Systemic). Management: Reduce the indinavir dose to 600 mg every 8 hours when given with ketoconazole. Monitor for increased systemic effects (including adverse/toxic effects) of ketoconazole. Risk D: Consider Therapy Modification
Indium 111 Capromab Pendetide: Coadministration of Antiandrogens and Indium 111 Capromab Pendetide may alter diagnostic results. Risk X: Avoid
Inhibitors of the Proton Pump (PPIs and PCABs): Ketoconazole (Systemic) may increase serum concentration of Inhibitors of the Proton Pump (PPIs and PCABs). Inhibitors of the Proton Pump (PPIs and PCABs) may decrease absorption of Ketoconazole (Systemic). Management: Administer ketoconazole with an acidic beverage, such as non-diet cola, to increase gastric acidity and improve absorption if concomitant use with proton pump inhibitors or potassium-competitive acid blockers is necessary. Risk D: Consider Therapy Modification
Irinotecan Products: Ketoconazole (Systemic) may increase active metabolite exposure of Irinotecan Products. Specifically, serum concentrations of SN-38 may be increased. Risk X: Avoid
Isavuconazonium Sulfate: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Isavuconazonium Sulfate. Specifically, CYP3A4 Inhibitors (Strong) may increase isavuconazole serum concentrations. Risk X: Avoid
Isoniazid: May decrease serum concentration of Ketoconazole (Systemic). Management: Avoid use of isoniazid from 2 weeks before and during treatment with ketoconazole when possible. If potential benefits outweigh the risks, monitor closely for reduced clinical response to ketoconazole and adjust the ketoconazole dose as needed. Risk D: Consider Therapy Modification
Isradipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Isradipine. Risk C: Monitor
Istradefylline: CYP3A4 Inhibitors (Strong) may increase serum concentration of Istradefylline. Management: Limit the maximum istradefylline dose to 20 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased istradefylline effects/toxicities. Risk D: Consider Therapy Modification
Itraconazole: CYP3A4 Inhibitors (Strong) may increase serum concentration of Itraconazole. Risk C: Monitor
Ivabradine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ivabradine. Risk X: Avoid
Ivacaftor: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full drug interaction monograph content for age- and weight-specific recommendations. Risk D: Consider Therapy Modification
Ivosidenib: Ketoconazole (Systemic) may increase serum concentration of Ivosidenib. Ivosidenib may decrease serum concentration of Ketoconazole (Systemic). Risk X: Avoid
Ixabepilone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ixabepilone. Management: Avoid use of ixabepilone and strong CYP3A4 inhibitors when possible. If combined, reduce the ixabepilone dose to 20 mg/m2. The previous ixabepilone dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Ketamine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ketamine. Risk C: Monitor
Lacidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lacidipine. Risk C: Monitor
Lapatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lapatinib. Management: Avoid use of lapatinib and strong CYP3A4 inhibitors when possible. If combined, a reduced lapatinib dose of 500 mg daily should be considered. The previous lapatinib dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Larotrectinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Larotrectinib. Management: Avoid use of strong CYP3A4 inhibitors with larotrectinib. If this combination cannot be avoided, reduce the larotrectinib dose by 50%. Increase to previous dose after stopping the inhibitor after a period of 3 to 5 times the inhibitor's half-life. Risk D: Consider Therapy Modification
Lefamulin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lefamulin. Management: Avoid concomitant use of lefamulin tablets and strong inhibitors of CYP3A4. Risk X: Avoid
Lemborexant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lemborexant. Risk X: Avoid
Leniolisib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Leniolisib. Risk X: Avoid
Lenvatinib: Ketoconazole (Systemic) may increase QTc-prolonging effects of Lenvatinib. Ketoconazole (Systemic) may increase serum concentration of Lenvatinib. Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Risk C: Monitor
Lercanidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lercanidipine. Risk X: Avoid
Leuprolide and Norethindrone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Leuprolide and Norethindrone. Specifically, concentrations of norethindrone may increase. Risk C: Monitor
Levamlodipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Levamlodipine. Risk C: Monitor
Levobupivacaine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Levobupivacaine. Risk C: Monitor
Levoketoconazole: CYP3A4 Inhibitors (Strong) may increase serum concentration of Levoketoconazole. Risk X: Avoid
Levomethadone: Ketoconazole (Systemic) may increase serum concentration of Levomethadone. Risk C: Monitor
Levomilnacipran: CYP3A4 Inhibitors (Strong) may increase serum concentration of Levomilnacipran. Management: The dose of levomilnacipran should not exceed 80 mg once daily when used with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Lidocaine (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Lidocaine (Systemic). Risk C: Monitor
Lomitapide: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lomitapide. Risk X: Avoid
Lonafarnib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lonafarnib. Risk X: Avoid
Lopinavir: Ketoconazole (Systemic) may increase serum concentration of Lopinavir. Lopinavir may increase serum concentration of Ketoconazole (Systemic). Management: Ketoconazole doses greater than 200 mg/day are not recommended in combination with lopinavir/ritonavir. Risk D: Consider Therapy Modification
Loratadine: Ketoconazole (Systemic) may increase serum concentration of Loratadine. Risk C: Monitor
Lorlatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lorlatinib. Management: Avoid use of lorlatinib with strong CYP3A4 inhibitors. If the combination cannot be avoided, reduce the lorlatinib dose from 100 mg once daily to 75 mg once daily, or from 75 mg once daily to 50 mg once daily. Risk D: Consider Therapy Modification
Lovastatin: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Lovastatin. CYP3A4 Inhibitors (Strong) may increase serum concentration of Lovastatin. Risk X: Avoid
Lumacaftor and Ivacaftor: Ketoconazole (Systemic) may increase serum concentration of Lumacaftor and Ivacaftor. Lumacaftor and Ivacaftor may decrease serum concentration of Ketoconazole (Systemic). Management: Consider alternatives to this combination. If combined, monitor for reduced ketoconazole serum concentrations and efficacy. If lumacaftor/ivacaftor is initiated in patients taking ketoconazole, lumacaftor/ivacaftor dose reductions are needed. Risk D: Consider Therapy Modification
Lumateperone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lumateperone. Management: Limit the lumateperone dose to 10.5 mg once daily when used with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Lurasidone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lurasidone. Risk X: Avoid
Lurbinectedin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Lurbinectedin. Management: Avoid concomitant use of lurbinectedin and strong CYP3A4 inhibitors. If coadministration with a strong CYP3A4 inhibitor cannot be avoided, reduce the lurbinectedin dose by 50%. Risk D: Consider Therapy Modification
Macitentan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Macitentan. Risk X: Avoid
Manidipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Manidipine. Management: Consider avoiding concomitant use of manidipine and strong CYP3A4 inhibitors. If combined, monitor closely for increased manidipine effects and toxicities. Manidipine dose reductions may be required. Risk D: Consider Therapy Modification
Maraviroc: CYP3A4 Inhibitors (Strong) may increase serum concentration of Maraviroc. Management: Reduce maraviroc to 150mg twice/day in adult and pediatrics weighing 40kg or more. See full interaction monograph for dose adjustments in pediatrics weighing 10 to less than 40kg. Do not use if CrCl less than 30mL/min or in those weighing less than 10 kg. Risk D: Consider Therapy Modification
Mavacamten: CYP2C19 Inhibitors (Weak) may increase serum concentration of Mavacamten. Management: Start mavacamten at 5 mg/day if stable on a weak CYP2C19 inhibitor, and reduce the mavacamten dose by one dose level if initiating a weak CYP2C19 inhibitor. Avoid initiating weak CYP2C19 inhibitors in patients on mavacamten 2.5 mg/day. Risk D: Consider Therapy Modification
Mavacamten: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mavacamten. Management: For patients on stable therapy with a strong CYP3A4 inhibitor initiate mavacamten at 2.5 mg daily. For patients initiating a strong CYP3A4 inhibitor during mavacamten therapy, dose reductions are recommended. See full mono for details. Risk D: Consider Therapy Modification
Mavorixafor: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mavorixafor. Management: Decrease the mavorixafor dose to 200 mg daily if combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Mefloquine: Ketoconazole (Systemic) may increase serum concentration of Mefloquine. Risk X: Avoid
Meperidine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Meperidine. Risk C: Monitor
Methadone: Ketoconazole (Systemic) may increase serum concentration of Methadone. Risk X: Avoid
MethylPREDNISolone: CYP3A4 Inhibitors (Strong) may increase serum concentration of MethylPREDNISolone. Risk C: Monitor
Midazolam: Ketoconazole (Systemic) may increase serum concentration of Midazolam. Management: Oral midazolam is contraindicated with ketoconazole. Avoid use with nasal midazolam. Consider alternatives to use with other routes of midazolam (IV, IM) when possible. Consider use of lower midazolam doses if combined. Risk X: Avoid
Midostaurin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Midostaurin. Management: Seek alternatives to the concomitant use of midostaurin and strong CYP3A4 inhibitors if possible. If concomitant use cannot be avoided, monitor patients for increased risk of adverse reactions. Risk D: Consider Therapy Modification
MiFEPRIStone: CYP3A4 Inhibitors (Strong) may increase serum concentration of MiFEPRIStone. Management: For treatment of hyperglycemia in Cushing's syndrome, start mifepristone at 300 mg/day, may titrate to a maximum of 900 mg/day. If starting a strong CYP3A4 inhibitor and taking > 300 mg/day mifepristone, decrease the mifepristone dose by 300 mg/day. Risk D: Consider Therapy Modification
Mirodenafil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mirodenafil. Management: Consider using a lower dose of mirodenafil when used with strong CYP3A4 inhibitors. Monitor for increased mirodenafil effects/toxicities with the use of this combination. Risk D: Consider Therapy Modification
Mirtazapine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mirtazapine. Risk C: Monitor
Mirvetuximab Soravtansine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mirvetuximab Soravtansine. Risk C: Monitor
Mitapivat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mitapivat. Risk X: Avoid
Mizolastine: Antifungal Agents (Azole Derivatives, Systemic) may increase serum concentration of Mizolastine. Risk X: Avoid
Mobocertinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Mobocertinib. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Mobocertinib. Risk X: Avoid
Mometasone (Nasal): CYP3A4 Inhibitors (Strong) may increase serum concentration of Mometasone (Nasal). Risk C: Monitor
Mometasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase serum concentration of Mometasone (Oral Inhalation). Risk C: Monitor
Mometasone (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Mometasone (Topical). Risk C: Monitor
Morphine (Systemic): P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Morphine (Systemic). Risk C: Monitor
Nadolol: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Nadolol. Risk C: Monitor
Naldemedine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Naldemedine. Risk C: Monitor
Nalfurafine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nalfurafine. Risk C: Monitor
Naloxegol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Naloxegol. Risk X: Avoid
Nelfinavir: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nelfinavir. Risk C: Monitor
Neratinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Neratinib. Risk X: Avoid
Nevirapine: May decrease serum concentration of Ketoconazole (Systemic). Management: Avoid use of nevirapine in the 2 weeks prior to and during ketoconazole therapy unless benefits outweigh the risk of diminished ketoconazole efficacy. Monitor ketoconazole efficacy and consider dose increases if combined. Risk D: Consider Therapy Modification
NiCARdipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of NiCARdipine. Risk C: Monitor
NIFEdipine (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of NIFEdipine (Topical). Risk X: Avoid
NIFEdipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of NIFEdipine. Management: Consider alternatives to this combination when possible. If combined, initiate nifedipine at the lowest dose available and monitor patients closely for increased nifedipine effects and toxicities (eg, hypotension, edema). Risk D: Consider Therapy Modification
Nilotinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nilotinib. Management: Avoid if possible. If coadministration cannot be avoided, nilotinib dose adjustments are recommended and depend on the dosage form of nilotinib used and indication treated. See full monograph for details. Risk D: Consider Therapy Modification
Nilvadipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nilvadipine. Risk C: Monitor
NiMODipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of NiMODipine. Risk X: Avoid
Nintedanib: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Nintedanib. Risk C: Monitor
Nirmatrelvir and Ritonavir: Ketoconazole (Systemic) may increase serum concentration of Nirmatrelvir and Ritonavir. Nirmatrelvir and Ritonavir may increase serum concentration of Ketoconazole (Systemic). Risk C: Monitor
Nirogacestat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nirogacestat. Risk X: Avoid
Nisoldipine: Ketoconazole (Systemic) may increase serum concentration of Nisoldipine. Risk X: Avoid
Nitrendipine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Nitrendipine. Risk C: Monitor
Olaparib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Olaparib. Management: Avoid use of strong CYP3A4 inhibitors with olaparib, if possible. If such concurrent use cannot be avoided, the dose of olaparib tablets should be reduced to 100 mg twice daily and the dose of olaparib capsules should be reduced to 150 mg twice daily. Risk D: Consider Therapy Modification
Oliceridine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Oliceridine. Risk C: Monitor
Olmutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Olmutinib. Risk C: Monitor
Omaveloxolone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Omaveloxolone. Management: Avoid this combination if possible. If coadministration is required, decrease the omaveloxolone dose to 50 mg daily and monitor closely for adverse reactions. Discontinue coadministration if adverse reactions occur. Risk D: Consider Therapy Modification
Ornidazole: Ketoconazole (Systemic) may increase serum concentration of Ornidazole. Risk C: Monitor
Osilodrostat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Osilodrostat. Management: Reduce osilodrostat dose by 50% during coadministration with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Ospemifene: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ospemifene. Risk C: Monitor
OxyBUTYnin: CYP3A4 Inhibitors (Strong) may increase serum concentration of OxyBUTYnin. Risk C: Monitor
OxyCODONE: CYP3A4 Inhibitors (Strong) may increase adverse/toxic effects of OxyCODONE. CYP3A4 Inhibitors (Strong) may increase serum concentration of OxyCODONE. Serum concentrations of the active metabolite oxymorphone may also be increased. Risk C: Monitor
PACLitaxel (Conventional): CYP3A4 Inhibitors (Strong) may increase serum concentration of PACLitaxel (Conventional). Risk C: Monitor
PACLitaxel (Protein Bound): CYP3A4 Inhibitors (Strong) may increase serum concentration of PACLitaxel (Protein Bound). Risk C: Monitor
Pacritinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pacritinib. Risk X: Avoid
Palbociclib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Palbociclib. Management: Avoid concurrent use of strong CYP3A4 inhibitors with palbociclib when possible. If the use of a strong CYP3A4 inhibitor cannot be avoided, decrease the palbociclib dose to 75 mg/day. Risk D: Consider Therapy Modification
Palovarotene: CYP3A4 Inhibitors (Strong) may increase serum concentration of Palovarotene. Risk X: Avoid
Panobinostat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Panobinostat. Management: Reduce the panobinostat dose to 10 mg when it must be used with a strong CYP3A4 inhibitor. Monitor patient response to therapy closely for evidence of more severe adverse effects related to panobinostat therapy. Risk D: Consider Therapy Modification
Parecoxib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Parecoxib. Specifically, serum concentrations of the active moiety valdecoxib may be increased. Risk C: Monitor
Paricalcitol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Paricalcitol. Risk C: Monitor
PAZOPanib: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of PAZOPanib. Risk X: Avoid
Pemigatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pemigatinib. Management: If combined use cannot be avoided, reduce the pemigatinib dose from 13.5 mg daily to 9 mg daily, or from 9 mg daily to 4.5 mg daily. Resume prior pemigatinib dose after stopping the strong inhibitor once 3 half-lives of the inhibitor has passed. Risk D: Consider Therapy Modification
Pexidartinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pexidartinib. Management: If combined use cannot be avoided, pexidartinib dose should be reduced as follows: reduce pexidartinib doses of 500 mg or 375 mg daily to 125 mg twice daily; reduce pexidartinib 250 mg daily to 125 mg once daily. Risk D: Consider Therapy Modification
Piflufolastat F18: Coadministration of Antiandrogens and Piflufolastat F18 may alter diagnostic results. Management: Therapies targeting the androgen pathway may result in changes in the uptake of piflufolastat F18 in prostate cancer. The impact of these therapies on the performance of piflufolastat F18 is unknown; consider use of alternative agents. Risk D: Consider Therapy Modification
Pimavanserin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pimavanserin. Management: Decrease the pimavanserin dose to 10 mg daily when combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Pimecrolimus: CYP3A4 Inhibitors (Strong) may decrease metabolism of Pimecrolimus. Risk C: Monitor
Pimozide: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pimozide. Risk X: Avoid
Piperaquine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Piperaquine. Risk C: Monitor
Pirtobrutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Pirtobrutinib. Management: Avoid concomitant use when possible. If combined, reduce the pirtobrutinib dose by 50 mg. If current dose is 50 mg, interrupt pirtobrutinib treatment during strong CYP3A4 inhibitor use. Risk D: Consider Therapy Modification
Polatuzumab Vedotin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Polatuzumab Vedotin. Exposure to unconjugated MMAE, the cytotoxic small molecule component of polatuzumab vedotin, may be increased. Risk C: Monitor
PONATinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of PONATinib. Management: Avoid concomitant use if possible. If combined, reduce ponatinib dose as follows: If taking 45 mg, reduce to 30 mg; if taking 30 mg, reduce to 15 mg; if taking 15 mg, reduce to 10 mg. If taking 10 mg, avoid concomitant use with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Pralsetinib: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Pralsetinib. Management: Avoid concomitant use if possible. If combined, reduce the pralsetinib dose. If taking 400 mg or 300 mg once daily, reduce to 200 mg once daily. If taking 200 mg once daily, reduce to 100 mg once daily. Risk D: Consider Therapy Modification
Prazepam: CYP3A4 Inhibitors (Strong) may increase serum concentration of Prazepam. Risk C: Monitor
Praziquantel: CYP3A4 Inhibitors (Strong) may increase serum concentration of Praziquantel. Risk C: Monitor
PrednisoLONE (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of PrednisoLONE (Systemic). Risk C: Monitor
PredniSONE: CYP3A4 Inhibitors (Strong) may increase serum concentration of PredniSONE. Risk C: Monitor
Propafenone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Propafenone. Risk C: Monitor
QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Caution) may increase QTc-prolonging effects of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Risk C: Monitor
QUEtiapine: CYP3A4 Inhibitors (Strong) may increase serum concentration of QUEtiapine. Management: In quetiapine treated patients, reduce quetiapine to one-sixth of original dose after starting a strong CYP3A4 inhibitor. In those on strong CYP3A4 inhibitors, start quetiapine at lowest dose and up-titrate as needed. Risk D: Consider Therapy Modification
Quinidine (Non-Therapeutic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Quinidine (Non-Therapeutic). Risk C: Monitor
QuiNIDine: Ketoconazole (Systemic) may increase QTc-prolonging effects of QuiNIDine. Ketoconazole (Systemic) may increase serum concentration of QuiNIDine. Risk X: Avoid
QuiNINE: CYP3A4 Inhibitors (Strong) may increase serum concentration of QuiNINE. Risk C: Monitor
Quizartinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Quizartinib. Management: If combination is necessary, reduce quizartinib dose as follows: from 53 mg daily to 26.5 mg daily; from 35.4 mg daily to 17.7 mg daily; from 26.5 mg daily to 17.7 mg daily. If taking 17.7 mg daily avoid quizartinib while on the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Radotinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Radotinib. Risk X: Avoid
Ramelteon: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ramelteon. Risk C: Monitor
Ranolazine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ranolazine. Risk X: Avoid
Reboxetine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Reboxetine. Risk C: Monitor
Red Yeast Rice: CYP3A4 Inhibitors (Strong) may increase serum concentration of Red Yeast Rice. Specifically, concentrations of lovastatin and related compounds found in Red Yeast Rice may be increased. Risk X: Avoid
Regorafenib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Regorafenib. CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Regorafenib. Risk X: Avoid
Relugolix, Estradiol, and Norethindrone: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Relugolix, Estradiol, and Norethindrone. Management: Avoid use of relugolix/estradiol/norethindrone with P-glycoprotein (P-gp) inhibitors. If concomitant use is unavoidable, relugolix/estradiol/norethindrone should be administered at least 6 hours before the P-gp inhibitor. Risk D: Consider Therapy Modification
Relugolix: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Relugolix. Management: Avoid coadministration of relugolix with oral P-gp inhibitors whenever possible. If combined, take relugolix at least 6 hours prior to the P-gp inhibitor and monitor patients more frequently for adverse reactions. Risk D: Consider Therapy Modification
Repaglinide: CYP3A4 Inhibitors (Strong) may increase serum concentration of Repaglinide. Risk C: Monitor
Repotrectinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Repotrectinib. Risk X: Avoid
Retapamulin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Retapamulin. Management: The use of retapamulin with strong CYP3A4 inhibitors is not recommended in patients less than 2 years old. No action is required in other populations. Risk C: Monitor
Revumenib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Revumenib. Management: If combined use is required, decrease revumenib dose for patients weighing 40 kg or more to 160 mg orally twice/day; for patients weighing less than 40 kg to 95 mg/m2 twice daily. Risk D: Consider Therapy Modification
Ribociclib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ribociclib. Management: Avoid use of ribociclib with strong CYP3A4 inhibitors when possible; if combined use cannot be avoided, reduce ribociclib dose to 400 mg once daily in advanced or metastatic breast cancer; reduce ribociclib dose to 200 mg daily in early breast cancer. Risk D: Consider Therapy Modification
Rifabutin: May decrease serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase serum concentration of Rifabutin. Management: The use of ketoconazole concurrently with or within 2 weeks of rifabutin is not recommended. If combined, monitor patients closely for evidence of diminished clinical response to ketoconazole and for increased rifabutin toxicities. Risk D: Consider Therapy Modification
RifAXIMin: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of RifAXIMin. Risk C: Monitor
Rilpivirine: Ketoconazole (Systemic) may increase serum concentration of Rilpivirine. Rilpivirine may decrease serum concentration of Ketoconazole (Systemic). Risk C: Monitor
Rimegepant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Rimegepant. Risk X: Avoid
Riociguat: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Riociguat. Management: Consider a riociguat starting dose of 0.5 mg 3 times a day when initiating riociguat in patients receiving strong CYP3A4 and P-gp inhibitors. Monitor for hypotension when these agents are combined and reduce the riociguat dose as needed. Risk D: Consider Therapy Modification
Ripretinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ripretinib. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Ripretinib. Risk C: Monitor
RisperiDONE: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of RisperiDONE. Risk C: Monitor
Ritonavir: May increase serum concentration of Ketoconazole (Systemic). Management: Limit the adult maximum ketoconazole dose to 200 mg/day in patients receiving ritonavir. Risk D: Consider Therapy Modification
Rivaroxaban: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase serum concentration of Rivaroxaban. Risk X: Avoid
Roflumilast-Containing Products: CYP3A4 Inhibitors (Strong) may increase serum concentration of Roflumilast-Containing Products. Risk C: Monitor
RomiDEPsin: CYP3A4 Inhibitors (Strong) may increase serum concentration of RomiDEPsin. Risk C: Monitor
Rupatadine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Rupatadine. Risk X: Avoid
Ruxolitinib (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Ruxolitinib (Systemic). Management: This combination should be avoided under some circumstances; dose adjustments may be required in some circumstances and depend on the indication for ruxolitinib. See monograph for details. Risk D: Consider Therapy Modification
Ruxolitinib (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Ruxolitinib (Topical). Risk X: Avoid
Saccharomyces boulardii: Antifungal Agents (Systemic and Oral [Non-Absorbable]) may decrease therapeutic effects of Saccharomyces boulardii. Risk X: Avoid
Salmeterol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Salmeterol. Risk X: Avoid
Saquinavir: May increase serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase serum concentration of Saquinavir. Management: Limit the adult maximum ketoconazole dose to 200 mg/day in patients receiving saquinavir/ritonavir. Risk D: Consider Therapy Modification
SAXagliptin: CYP3A4 Inhibitors (Strong) may increase serum concentration of SAXagliptin. Management: Limit the saxagliptin dose to 2.5 mg daily when combined with strong CYP3A4 inhibitors. When using the saxagliptin combination products saxagliptin/dapagliflozin or saxagliptin/dapagliflozin/metformin, avoid use with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Selpercatinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Selpercatinib. Management: Avoid combination if possible. If use is necessary, reduce selpercatinib dose as follows: from 120 mg twice/day to 40 mg twice/day, or from 160 mg twice/day to 80 mg twice/day. Risk D: Consider Therapy Modification
Selumetinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Selumetinib. Management: Avoid concomitant use when possible. If combined, selumetinib dose reductions are recommended and vary based on body surface area and selumetinib dose. For details, see the full drug interaction monograph or selumetinib prescribing information. Risk D: Consider Therapy Modification
Sertindole: CYP3A4 Inhibitors (Strong) may increase serum concentration of Sertindole. Risk X: Avoid
Sildenafil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Sildenafil. Management: Use of sildenafil for pulmonary arterial hypertension (PAH) should be avoided with strong CYP3A4 inhibitors. When used for erectile dysfunction, consider using a lower starting dose of 25 mg and monitor patients for sildenafil toxicities. Risk D: Consider Therapy Modification
Silodosin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Silodosin. Risk X: Avoid
Simeprevir: CYP3A4 Inhibitors (Strong) may increase serum concentration of Simeprevir. Risk X: Avoid
Simvastatin: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Simvastatin. CYP3A4 Inhibitors (Strong) may increase serum concentration of Simvastatin. Risk X: Avoid
Sirolimus (Conventional): CYP3A4 Inhibitors (Strong) may increase serum concentration of Sirolimus (Conventional). Management: Avoid concurrent use of sirolimus with strong CYP3A4 inhibitors when possible and alternative agents with lesser interaction potential with sirolimus should be considered. Concomitant use of sirolimus and voriconazole or posaconazole is contraindicated. Risk D: Consider Therapy Modification
Sirolimus (Conventional): P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Sirolimus (Conventional). Management: Avoid concurrent use of sirolimus with P-glycoprotein (P-gp) inhibitors when possible and alternative agents with lesser interaction potential with sirolimus should be considered. Monitor for increased sirolimus concentrations/toxicity if combined. Risk D: Consider Therapy Modification
Sirolimus (Protein Bound): CYP3A4 Inhibitors (Strong) may increase serum concentration of Sirolimus (Protein Bound). Risk X: Avoid
Sirolimus (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Sirolimus (Topical). Risk C: Monitor
Solifenacin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Solifenacin. Management: Limit adult solifenacin doses to 5 mg daily and limit doses in pediatric patients to the recommended weight-based starting dose (and do not increase the dose) when combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Sonidegib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Sonidegib. Risk X: Avoid
Sparsentan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Sparsentan. Risk X: Avoid
Sucralfate: May decrease serum concentration of Ketoconazole (Systemic). Risk C: Monitor
SUFentanil: CYP3A4 Inhibitors (Strong) may increase serum concentration of SUFentanil. Management: If a strong CYP3A4 inhibitor is initiated in a patient on sufentanil, consider a sufentanil dose reduction and monitor for increased sufentanil effects and toxicities (eg, respiratory depression). Risk D: Consider Therapy Modification
SUNItinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of SUNItinib. Management: Avoid when possible. If combined, decrease sunitinib dose to a minimum of 37.5 mg daily when treating GIST or RCC. Decrease sunitinib dose to a minimum of 25 mg daily when treating PNET. Monitor patients for both reduced efficacy and increased toxicities. Risk D: Consider Therapy Modification
Suvorexant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Suvorexant. Risk X: Avoid
Suzetrigine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Suzetrigine. Risk X: Avoid
Tacrolimus (Systemic): Ketoconazole (Systemic) may increase serum concentration of Tacrolimus (Systemic). Management: Tacrolimus dose adjustment may be required; empiric dose reductions of 50% have been recommended. Monitor tacrolimus concentrations and clinical response closely. Risk D: Consider Therapy Modification
Tacrolimus (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Tacrolimus (Topical). Risk C: Monitor
Tadalafil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tadalafil. Management: Avoid this combination in patients taking tadalafil for pulmonary arterial hypertension. In patients taking tadalafil for ED or BPH, max tadalafil dose is 2.5 mg if taking daily or 10 mg no more frequently than every 72 hours if used as needed. Risk D: Consider Therapy Modification
Talazoparib: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Talazoparib. Risk C: Monitor
Tamsulosin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tamsulosin. Risk X: Avoid
Tasimelteon: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tasimelteon. Risk C: Monitor
Tazemetostat: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tazemetostat. Risk X: Avoid
Temsirolimus: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Temsirolimus. Specifically, concentrations of sirolimus may be increased. Management: Avoid concomitant use of temsirolimus and strong CYP3A4 inhibitors. If coadministration is unavoidable, decrease temsirolimus dose to 12.5 mg per week. Resume previous temsirolimus dose 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Teneligliptin: Ketoconazole (Systemic) may increase serum concentration of Teneligliptin. Risk C: Monitor
Teniposide: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Teniposide. Risk C: Monitor
Tenofovir Disoproxil Fumarate: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Tenofovir Disoproxil Fumarate. Risk C: Monitor
Tetrahydrocannabinol and Cannabidiol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tetrahydrocannabinol and Cannabidiol. Risk C: Monitor
Tetrahydrocannabinol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tetrahydrocannabinol. Risk C: Monitor
Tezacaftor and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tezacaftor and Ivacaftor. Management: If combined with strong CYP3A4 inhibitors, tezacaftor/ivacaftor should be administered in the morning, twice a week, approximately 3 to 4 days apart. Tezacaftor/ivacaftor dose depends on age and weight; see full Lexi-Interact monograph for details. Risk D: Consider Therapy Modification
Thiotepa: CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Thiotepa. CYP3A4 Inhibitors (Strong) may increase serum concentration of Thiotepa. Management: Avoid coadministration of thiotepa and strong CYP3A4 inhibitors. If concomitant use cannot be avoided, monitor for thiotepa adverse effects and decreased efficacy. Risk D: Consider Therapy Modification
Ticagrelor: CYP3A4 Inhibitors (Strong) may decrease active metabolite exposure of Ticagrelor. CYP3A4 Inhibitors (Strong) may increase serum concentration of Ticagrelor. Risk X: Avoid
Tilidine: CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Tilidine. CYP3A4 Inhibitors (Strong) may increase serum concentration of Tilidine. Risk C: Monitor
Tipranavir: May increase serum concentration of Ketoconazole (Systemic). Management: Adult ketoconazole doses greater than 200 mg/day are not recommended in patients treated with tipranavir. Risk D: Consider Therapy Modification
Tisotumab Vedotin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tisotumab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Risk C: Monitor
Tofacitinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tofacitinib. Management: Tofacitinib dose reductions are recommended when combined with strong CYP3A4 inhibitors. Recommended dose adjustments vary by tofacitinib formulation and therapeutic indication. See full Lexi Interact monograph for details. Risk D: Consider Therapy Modification
Tolterodine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tolterodine. Management: The maximum recommended dose of tolterodine is 2 mg per day (1 mg twice daily for immediate-release tablets or 2 mg daily for extended-release capsules) when used together with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Tolvaptan: CYP3A4 Inhibitors (Strong) may increase serum concentration of Tolvaptan. Risk X: Avoid
Topotecan: P-glycoprotein/ABCB1 Inhibitors may increase serum concentration of Topotecan. Risk X: Avoid
Toremifene: CYP3A4 Inhibitors (Strong) may increase serum concentration of Toremifene. Management: Use of toremifene with strong CYP3A4 inhibitors should be avoided if possible. If coadministration is necessary, monitor for increased toremifene toxicities, including QTc interval prolongation. Risk D: Consider Therapy Modification
Trabectedin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Trabectedin. Risk X: Avoid
TraMADol: CYP3A4 Inhibitors (Strong) may increase serum concentration of TraMADol. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of TraMADol. Risk C: Monitor
TraZODone: CYP3A4 Inhibitors (Strong) may increase serum concentration of TraZODone. Management: Consider the use of a lower trazodone dose and monitor for increased trazodone effects (eg, sedation, QTc prolongation) if combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Tretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Tretinoin (Systemic). Management: Avoid use of tretinoin and strong CYP3A4 inhibitors when possible. If combined, monitor for increased tretinoin concentrations and toxicities (eg, pseudotumor cerebri, hypercalcemia). Risk D: Consider Therapy Modification
Triamcinolone (Nasal): CYP3A4 Inhibitors (Strong) may increase serum concentration of Triamcinolone (Nasal). Risk C: Monitor
Triamcinolone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Triamcinolone (Ophthalmic). Risk C: Monitor
Triamcinolone (Systemic): CYP3A4 Inhibitors (Strong) may increase serum concentration of Triamcinolone (Systemic). Management: Consider alternatives to this combination when possible. If combined, monitor for increased corticosteroid adverse effects during coadministration of triamcinolone and strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Triamcinolone (Topical): CYP3A4 Inhibitors (Strong) may increase serum concentration of Triamcinolone (Topical). Risk C: Monitor
Triazolam: CYP3A4 Inhibitors (Strong) may increase serum concentration of Triazolam. Risk X: Avoid
Ubrogepant: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ubrogepant. Risk X: Avoid
Udenafil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Udenafil. Risk X: Avoid
Ulipristal: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ulipristal. Risk C: Monitor
Upadacitinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Upadacitinib. Management: Upadacitinib dose adjustments are often needed when combined with strong CYP3A4 inhibitors. Specific adjustments vary based on upadacitinib indication. See full interact monograph for details. Risk D: Consider Therapy Modification
Valbenazine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Valbenazine. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Valbenazine. Management: Reduce the valbenazine dose to 40 mg daily when combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Vamorolone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vamorolone. Management: Reduce the vamorolone dose to 4 mg/kg daily, with a maximum dose of 200 mg daily for patients weighing over 50 kg, when combined with strong CYP3A4 inhibitors. Risk D: Consider Therapy Modification
Vanzacaftor, Tezacaftor, and Deutivacaftor: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vanzacaftor, Tezacaftor, and Deutivacaftor. Management: Age- and weight-specific dose reductions of vanzacaftor, tezacaftor, and deutivacaftor are recommended. Please see full Interact monograph or labeling for details. Risk D: Consider Therapy Modification
Vardenafil: Ketoconazole (Systemic) may increase serum concentration of Vardenafil. Management: Limit Levitra (vardenafil) dose to 5 mg per 24 hours with ketoconazole 200 mg/day and 2.5 mg per 24 hours with ketoconazole 400 mg/day. Avoid concomitant use of Staxyn (vardenafil) and ketoconazole. Combined use is contraindicated outside of the US. Risk D: Consider Therapy Modification
Vemurafenib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vemurafenib. Management: Avoid concurrent use of vemurafenib with strong CYP3A4 inhibitors when possible. If concomitant use is unavoidable, consider a vemurafenib dose reduction if clinically indicated. Risk D: Consider Therapy Modification
Venetoclax: CYP3A4 Inhibitors (Strong) may increase serum concentration of Venetoclax. Management: Coadministration is contraindicated during venetoclax initiation and ramp-up in CLL/SLL patients. Reduced venetoclax doses are required during ramp-up for patients with AML, and all maintenance therapy. See full Lexi Interact monograph for details. Risk D: Consider Therapy Modification
Verapamil: CYP3A4 Inhibitors (Strong) may increase serum concentration of Verapamil. Risk C: Monitor
Vilanterol: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vilanterol. Risk C: Monitor
Vilazodone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vilazodone. Management: Limit the maximum vilazodone dose to 20 mg daily in patients receiving strong CYP3A4 inhibitors. The original vilazodone dose can be resumed following discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
VinBLAStine: CYP3A4 Inhibitors (Strong) may increase serum concentration of VinBLAStine. Risk C: Monitor
VinCRIStine: CYP3A4 Inhibitors (Strong) may increase serum concentration of VinCRIStine. Risk X: Avoid
Vindesine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vindesine. Risk C: Monitor
Vinflunine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vinflunine. CYP3A4 Inhibitors (Strong) may increase active metabolite exposure of Vinflunine. Risk X: Avoid
Vinorelbine: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vinorelbine. Risk C: Monitor
Vitamin K Antagonists: Ketoconazole (Systemic) may increase serum concentration of Vitamin K Antagonists. Risk C: Monitor
Voclosporin: CYP3A4 Inhibitors (Strong) may increase serum concentration of Voclosporin. Risk X: Avoid
Vorapaxar: CYP3A4 Inhibitors (Strong) may increase serum concentration of Vorapaxar. Risk X: Avoid
Voriconazole: CYP3A4 Inhibitors (Strong) may increase serum concentration of Voriconazole. Risk C: Monitor
Zanubrutinib: CYP3A4 Inhibitors (Strong) may increase serum concentration of Zanubrutinib. Management: Decrease the zanubrutinib dose to 80 mg once daily during coadministration with a strong CYP3A4 inhibitor. Further dose adjustments may be required for zanubrutinib toxicities, refer to prescribing information for details. Risk D: Consider Therapy Modification
Ziprasidone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Ziprasidone. Risk C: Monitor
Zolpidem: CYP3A4 Inhibitors (Strong) may increase serum concentration of Zolpidem. Risk C: Monitor
Zopiclone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Zopiclone. Management: If coadministered with strong CYP3A4 inhibitors, initiate zopiclone at 3.75 mg in adults, with a maximum dose of 5 mg. Monitor for zopiclone toxicity (eg, drowsiness, confusion, lethargy, ataxia, respiratory depression). Risk D: Consider Therapy Modification
Zuranolone: CYP3A4 Inhibitors (Strong) may increase serum concentration of Zuranolone. Management: Reduce the zuranolone dose to 30 mg once daily when used concomitantly with a strong CYP3A4 inhibitor. Risk D: Consider Therapy Modification
Patients with Cushing syndrome often experience oligomenorrhea or amenorrhea due to the pathological cortisol excess associated with this disease. Patients treated with ketoconazole may experience a decrease in ovulatory disturbances and should be informed of the potential return of fertility (Berwaerts 1999; Bronstein 2015; Brue 2018).
The use of ketoconazole in male patients has been associated with decreased testosterone concentrations. Effects are dose related and reversible when ketoconazole is discontinued. Testosterone levels become impaired with doses of 800 mg/day. Adverse effects have included reversible gynecomastia, oligospermia, and impotence.
Based on the mechanism of action, in utero ketoconazole exposure may theoretically cause adverse events in the fetus (Pilmis 2015).
Agents other than ketoconazole are recommended for the treatment of systemic fungal infections in pregnant patients (Pilmis 2015).
Untreated Cushing syndrome during pregnancy may cause adverse events in the mother and fetus. Data related to ketoconazole for the treatment of Cushing disease (off-label use) during pregnancy are limited. Medication may be considered for patients when surgery is not an option or for symptomatic control at initial diagnosis (ESE [Luger 2021]).
Ketoconazole is present in breast milk.
Milk concentrations following an oral ketoconazole dose of 200 mg daily for 10 days were ≤0.22 mcg/mL in a case report. Using the reported peak milk concentration of 0.22 mcg/mL in this patient, authors of the study calculated the estimated exposure to the breastfeeding infant to be 0.033 mg/kg/day (relative infant dose: 1.4% based on the weight-adjusted maternal dose of 200 mg/day) (Moretti 1995).
Breastfeeding is not recommended by the manufacturer.
Hepatic function tests (baseline and frequently during therapy), including weekly ALT for the duration of treatment; Canadian labeling recommends monitoring hepatic function at baseline, at weeks 2 and 4, and monthly thereafter; calcium and phosphorous (periodically with long-term use); adrenal function as clinically necessary.
Cushing syndrome: Monitor cortisol (24-hour urinary free cortisol, morning serum cortisol, and/or serum cortisol day curves) 1 to 2 weeks after initiation or dosage adjustments until levels normalize, then periodically thereafter (Castinetti 2021; ES [Nieman 2015]).
Alters the permeability of the cell wall by blocking fungal cytochrome P450; inhibits biosynthesis of triglycerides and phospholipids by fungi; inhibits several fungal enzymes that results in a build-up of toxic concentrations of hydrogen peroxide; also inhibits several adrenal enzymes (CYP11A1 [cholesterol side chain cleavage enzyme], CYP17 [17 alpha-hydroxylase], CYP11B1 [11 beta-hydroxylase], CYP11B2 [aldosterone synthase]) responsible for androgen and cortisol synthesis (Castinetti 2021).
Distribution: Well into inflamed joint fluid, saliva, bile, urine, sebum, cerumen, feces, tendons, skin and soft tissue, and testes; crosses blood-brain barrier poorly; only negligible amounts reach CSF.
Protein binding: ~99% (mainly albumin).
Metabolism: Partially hepatic via CYP3A4 to inactive metabolites.
Bioavailability: Decreases as gastric pH increases.
Half-life elimination: Biphasic: Initial: 2 hours; Terminal: 8 hours.
Time to peak, serum: 1 to 2 hours.
Excretion: Feces (57%); urine (13% [2% to 4% unchanged]).
