Version July 2025
Codeine/chlorpheniramine exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death. Reserve codeine/chlorpheniramine for use in adult patients for whom the benefits of cough suppression are expected to outweigh the risks, and in whom an adequate assessment of the etiology of the cough has been made. Assess each patient’s risk prior to prescribing codeine/chlorpheniramine, prescribe codeine/chlorpheniramine for the shortest duration that is consistent with individual patient treatment goals, monitor all patients regularly for the development of addiction or abuse, and refill only after reevaluation of the need for continued treatment.
Serious, life-threatening, or fatal respiratory depression may occur with use of codeine/chlorpheniramine. Monitor for respiratory depression, especially during initiation of codeine/chlorpheniramine therapy or when used in patients at higher risk.
Accidental ingestion of even one dose of codeine/chlorpheniramine, especially by children, can result in a fatal overdose of codeine.
Life-threatening respiratory depression and death have occurred in children who received codeine. Most of the reported cases occurred following tonsillectomy and/or adenoidectomy and many of the children had evidence of being ultra-rapid metabolizers of codeine due to a CYP450 2D6 polymorphism. Codeine/chlorpheniramine is contraindicated in pediatric patients <12 years and pediatric patients <18 years following tonsillectomy and/or adenoidectomy. Avoid the use of codeine/chlorpheniramine in pediatric patients 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine.
Ensure accuracy when prescribing, dispensing, and administering codeine/chlorpheniramine. Dosing errors can result in accidental overdose and death. Always use an accurate milliliter measuring device when measuring and administering codeine/chlorpheniramine.
The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex, requiring careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine. Avoid the use of codeine/chlorpheniramine in patients who are taking a CYP3A4 inhibitor, CYP3A4 inducer, or 2D6 inhibitor.
Concomitant use of opioids with benzodiazepines or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Avoid use of codeine/chlorpheniramine in patients taking benzodiazepines, other CNS depressants, or alcohol.
Codeine/chlorpheniramine is not recommended for use in pregnant women. Prolonged use of codeine/chlorpheniramine during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. If codeine/chlorpheniramine is used for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available.
Dosage guidance:
Safety: Consider prescribing naloxone or nalmefene for patients with factors associated with an increased risk for overdose, such as history of overdose or substance use disorder, patients with sleep-disordered breathing, higher opioid dosages (≥50 morphine milligram equivalents [MME]/day orally), and/or concomitant benzodiazepine use (Ref).
Dosage form information: Tuzistra XR oral suspension has been discontinued in the United States for >1 year.
Cough and upper respiratory symptoms: Oral:
Suspension (extended release): 10 mL every 12 hours; maximum dose: 20 mL per 24 hours.
Tablet (extended release): 1 tablet every 12 hours; maximum dose: 2 tablets per 24 hours.
Discontinuation of therapy: Decrease dose by 25% to 50% every 2 to 4 days; monitor carefully for signs/symptoms of withdrawal. If patient displays withdrawal symptoms, increase dose to previous level and then reduce dose more slowly by increasing interval between dose reductions, decreasing amount of daily dose reduction, or both. Do not abruptly discontinue.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no specific dosage adjustments provided in the manufacturer’s labeling; use with caution in severe renal impairment.
There are no specific dosage adjustments provided in the manufacturer’s labeling; use with caution in severe hepatic impairment.
Avoid use (Ref).
The following adverse drug reactions are derived from product labeling unless otherwise specified. Adverse reactions reported with combination product and/or individual agents. Also see individual agents.
Frequency not defined:
Cardiovascular: Chest pain, chest tightness, decreased heart rate, facial flushing, hypertension, hypotension, orthostatic hypotension, palpitations, peripheral edema, prolonged QT interval on ECG, shock, syncope, tachycardia
Dermatologic: Dermatitis, diaphoresis, erythema of skin, hyperhidrosis, pruritus, skin rash, urticaria
Endocrine & metabolic: Altered serum glucose (change in glucose utilization), gynecomastia, hot flash, increased libido, pheochromocytoma crisis
Gastrointestinal: Abdominal distention, abdominal pain, acute pancreatitis, anorexia, biliary tract spasm, constipation, decreased appetite, decreased gastrointestinal motility, diarrhea, dyspepsia, dysphagia, epigastric distress, gastroesophageal reflux disease, hiccups, increased appetite, increased serum amylase, intestinal obstruction, nausea, paralytic ileus, spasm of sphincter of Oddi, vomiting, xerostomia
Genitourinary: Detrusor hyperreflexia of bladder, dysuria, early menses, genitourinary tract spasm (vesicle sphincter), glycosuria, hypogonadism, infertility, lactation insufficiency, ureteral spasm, urinary frequency, urinary hesitancy, urinary retention, urinary tract infection
Hematologic & oncologic: Agranulocytosis, aplastic anemia, thrombocytopenia
Hypersensitivity: Anaphylaxis, facial swelling
Nervous system: Agitation, allodynia (opioid-induced hyperalgesia) (FDA Safety Communication 2023), anxiety, asthenia, ataxia, coma, confusion, decreased mental acuity, depression, dizziness, drowsiness, drug abuse, dysphoria, euphoria, excitability, falling, false sense of well-being, fatigue, fear, hallucination, headache, increased intracranial pressure, insomnia, irritability, lethargy, malaise, migraine, neonatal withdrawal, nervousness, opioid dependence, opioid withdrawal syndrome, relaxation, restlessness, sedated state, seizure, tremor, vertigo
Neuromuscular & skeletal: Arthralgia, back pain, dyskinesia, facial dyskinesia, laryngospasm (allergic), muscle spasm
Ophthalmic: Blurred vision, diplopia, hypermetropia, increased lacrimation, miosis, mydriasis, photophobia, visual disturbance
Otic: Labyrinthitis, tinnitus
Respiratory: Allergic bronchospastic disease, atelectasis, bronchitis, cough, dry nose, dry throat, dyspnea, laryngismus, nasal congestion, nasopharyngitis, respiratory depression, respiratory distress, sinusitis, thickening of bronchial secretions, upper respiratory tract infection, wheezing
Miscellaneous: Impaired physical performance
Hypersensitivity to codeine, chlorpheniramine, or any component of the formulation; significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment; known or suspected gastrointestinal obstruction, including paralytic ileus; concurrent use with monoamine oxidase inhibitors (MAOIs) or use of MAOIs within the last 14 days; pediatric patients <12 years of age; postoperative management in pediatric patients <18 years of age who have undergone tonsillectomy and/or adenoidectomy.
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Concerns related to adverse effects:
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Constipation: May cause or aggravate constipation; chronic use may result in obstructive bowel disease, particularly in those with underlying intestinal motility disorders. May also be problematic in patients with unstable angina and patients post-myocardial infarction.
• Hyperalgesia: Opioid-induced hyperalgesia (OIH) has occurred with short-term and prolonged use of opioid analgesics. Symptoms may include increased levels of pain upon opioid dosage increase, decreased levels of pain upon opioid dosage decrease, or pain from ordinarily nonpainful stimuli; symptoms may be suggestive of OIH if there is no evidence of underlying disease progression, opioid tolerance, opioid withdrawal, or addictive behavior. Consider decreasing the current opioid dose or opioid rotation in patients who experience OIH.
• Hypotension: May cause severe hypotension (including orthostasis and syncope); risk is increased in patients with reduced blood volume or taking concurrent CNS depressants (eg, phenothiazines, general anesthetics). Avoid use in patients with circulatory shock.
• Phenanthrene hypersensitivity: Use with caution in patients with hypersensitivity reactions to other phenanthrene-derivative opioid agonists (hydrocodone, hydromorphone, levorphanol, oxycodone, oxymorphone).
• Respiratory depression: Fatal respiratory depression may occur. Carbon dioxide retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids. Patients and caregivers should be educated on how to recognize respiratory depression and the importance of getting emergency assistance immediately (eg, calling 911) in the event of known or suspected overdose.
Disease-related concerns:
• Abdominal conditions: May obscure diagnosis or clinical course of patients with acute abdominal conditions. Use with caution in patients with underlying intestinal motility disorders; may result in constipation or obstructive bowel disease. Use is contraindicated with known or suspected gastrointestinal obstruction, including paralytic ileus.
• Adrenocortical insufficiency: Use with caution in patients with adrenal insufficiency, including Addison disease. Long-term opioid use may cause secondary hypogonadism, which may lead to mood disorders and osteoporosis (Brennan 2013).
• Biliary tract impairment: Use with caution in patients with biliary tract dysfunction or acute pancreatitis; opioids may cause constriction of sphincter of Oddi and increase biliary tract pressure.
• Delirium tremens: Use with caution in patients with delirium tremens.
• Head trauma: Avoid use in patients with head injury, intracranial lesions, or elevated intracranial pressure (ICP); exaggerated elevation of ICP may occur.
• Hepatic impairment: Use with caution in patients with severe hepatic impairment.
• Obesity: Use with caution in patients who are morbidly obese.
• Prostatic hyperplasia/urinary obstruction: Use with caution in patients with prostatic hyperplasia and/or urinary stricture.
• Psychosis: Use with caution in patients with toxic psychosis.
• Renal impairment: Use with caution in patients with severe renal impairment.
• Respiratory disease: Use with caution and monitor for respiratory depression in patients with significant chronic obstructive pulmonary disease or cor pulmonale, and those having a substantially decreased respiratory reserve, hypoxia, hypercarbia, or preexisting respiratory depression, particularly when initiating therapy; critical respiratory depression may occur, even at therapeutic dosages. Avoid use in patients with acute febrile illness associated with productive cough or in patients with chronic respiratory disease unable to clear secretions. Use is contraindicated in patients with acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment.
• Seizures: Use with caution in patients with a history of seizure disorder; may cause or exacerbate preexisting seizures.
• Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.
Concurrent drug therapy issues:
• Benzodiazepines or other CNS depressants: Concomitant use may result in respiratory depression and sedation, which may be fatal. Consider prescribing naloxone or nalmefene for emergency treatment of opioid overdose in patients taking benzodiazepines or other CNS depressants concomitantly with opioids.
Special populations:
• CYP2D6 "poor metabolizers": Poor metabolizers have decreased metabolism of codeine to its active metabolite, which may diminish analgesia; avoid the use of codeine and consider alternatives that are not metabolized by CYP2D6 (CPIC [Crews 2021]).
• CYP2D6 "ultrarapid metabolizers": Ultrarapid metabolizers have increased metabolism of codeine to its active metabolite, which may increase the risk of serious adverse effects; avoid the use of codeine and consider alternatives that are not metabolized by CYP2D6 (CPIC [Crews 2021]). The prevalence of this phenotype is estimated to be 1% to 10% for White (European and North American) patients; 3% to 4% for Black patients; 1% to 2% for Chinese, Japanese, and Korean patients; and >10% in certain ethnic groups, such as Oceanian, Northern African, Middle Eastern, Ashkenazi Jew, and Puerto Rican patients.
• Cachectic or debilitated patients: Use with caution in cachectic or debilitated patients; there is a greater potential for critical respiratory depression, even at therapeutic dosages.
• Older adult: Use with caution in older adults; may be more sensitive to adverse effects.
• Neonates: Neonatal withdrawal syndrome: Signs and symptoms include irritability, hyperactivity and abnormal sleep pattern, high-pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. Onset, duration, and severity depend on the drug used, duration of use, maternal dose, and rate of drug elimination by the newborn.
• Pediatric: Respiratory depression: Risk factors include conditions associated with hypoventilation, such as postoperative status, obstructive sleep apnea, obesity, severe pulmonary disease, neuromuscular disease, and concomitant use of other medications that cause respiratory depression. Deaths have also occurred in breastfeeding infants after being exposed to high concentrations of morphine because the mothers were ultra-rapid metabolizers.
Dosage form specific issues:
• Polysorbate 80: Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson 2002; Lucente 2000; Shelley 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade 1986; CDC 1984). See manufacturer's labeling.
Other warnings/precautions:
• Abuse/misuse/diversion: Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists; do not abruptly discontinue in a physically dependent patient. Other risk factors associated with increased risk include a personal or family history of substance use disorder or mental illness (eg, major depression).
• Cough: Appropriate use: Underlying cause of cough should be determined prior to prescribing and re-evaluated within 5 days for an unresponsive cough. Reserve for use in adult patients where benefits of cough suppression outweigh the risks and in patients who have had an adequate assessment of cough etiology.
• Naloxone/nalmefene access: Discuss the availability of naloxone or nalmefene with all patients who are prescribed opioid analgesics, as well as their caregivers, and consider prescribing it to patients who are at increased risk of opioid overdose. These include patients who are also taking benzodiazepines or other CNS depressants, have an opioid use disorder (OUD) (current or history of), or have experienced a previous opioid overdose. Additionally, health care providers should consider prescribing naloxone or nalmefene to patients prescribed medications to treat OUD; patients at risk of opioid overdose even if they are not taking an opioid analgesic or medication to treat OUD; and patients taking opioids, including methadone or buprenorphine for OUD, if they have household members, including children, or other close contacts at risk for accidental ingestion or opioid overdose. Inform patients and caregivers on options for obtaining naloxone or nalmefene (eg, by prescription, directly from a pharmacist, a community-based program) as permitted by state dispensing and prescribing guidelines. Educate patients and caregivers on how to recognize respiratory depression, proper administration of naloxone or nalmefene, and getting emergency help (FDA 2020).
Tuzistra XR oral suspension has been discontinued in the United States for >1 year.
Tuzistra XR's formulation provides codeine and chlorpheniramine equivalent to that in codeine phosphate 20 mg and chlorpheniramine maleate 4 mg per 5 mL
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Suspension Extended Release, Oral:
Tuzistra XR: Codeine polistirex 14.7 mg and chlorpheniramine polistirex 2.8 mg per 5 mL (473 mL [DSC]) [contains methylparaben, polysorbate 80, propylparaben; cherry flavor]
Tablet Extended Release 12 Hour, Oral:
Tuxarin ER: Codeine phosphate 54.3 mg and chlorpheniramine maleate 8 mg
No
Tablet, 12-hour (Tuxarin ER Oral)
54.3-8 mg (per each): $2.19
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.
C-III
Administer with or without food. Shake extended-release suspension well before use. Administer with an accurate milliliter oral measuring device; do not use a household teaspoon to measure dose (overdosage may occur). Do not dilute with fluids or mix together with other drugs.
An FDA-approved patient medication guide, which is available with the product information and as follows, must be dispensed with this medication:
Tuxarin ER: https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/206323s005lbl.pdf#page=15
Tuzistra XR: https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/207768s013lbl.pdf#page=27
Cough and upper respiratory symptoms: Temporary relief of cough and upper respiratory symptoms associated with allergy or the common cold in patients ≥18 years of age.
Limitations of use: Because the risks of addiction, abuse, and misuse with opioids, even at recommended doses, reserve codeine/chlorpheniramine for use in adults for whom the benefits of cough suppression are expected to outweigh the risks, and in whom adequate assessment of the etiology of the cough has been made.
The Institute for Safe Medication Practices (ISMP) includes this medication among its list of drug classes (opioids, all formulations and routes of administration) which have a heightened risk of causing significant patient harm when used in error (High-Alert Medications in Acute Care, Community/Ambulatory Care, and Long-Term Care Settings).
Beers Criteria: Chlorpheniramine, a first-generation antihistamine, is identified in the Beers Criteria as a potentially inappropriate medication to be avoided in patients ≥65 years (independent of diagnosis or condition) due to its potent anticholinergic properties resulting in increased risk of confusion, dry mouth, constipation, and other anticholinergic effects or toxicity; use should also be avoided due to reduced clearance with advanced age and tolerance associated with use as a hypnotic. Exposure to concurrent anticholinergic drugs also increases risk of falls, delirium, and dementia; consider total anticholinergic burden when conducting medication reviews (Beers Criteria [AGS 2023]).
KIDs List: Codeine, when used in pediatric patients <18 years of age, is identified on the Key Potentially Inappropriate Drugs in Pediatrics (KIDs) list and should be avoided due to risk of respiratory depression and death unless pharmacogenetic testing completed (strong recommendation; high quality of evidence) (PPA [Meyers 2020]).
Refer to individual components.
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.
Acetylcholinesterase Inhibitors: May decrease therapeutic effects of Agents with Clinically Relevant Anticholinergic Effects. Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Acetylcholinesterase Inhibitors. Risk C: Monitor
Aclidinium: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Ajmaline: May increase serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor
Alizapride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Alvimopan: Opioid Agonists may increase adverse/toxic effects of Alvimopan. This is most notable for patients receiving long-term (i.e., more than 7 days) opiates prior to alvimopan initiation. Management: Alvimopan is contraindicated in patients receiving therapeutic doses of opioids for more than 7 consecutive days immediately prior to alvimopan initiation. Risk D: Consider Therapy Modification
Amantadine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Amezinium: Antihistamines may increase stimulatory effects of Amezinium. Risk C: Monitor
Amisulpride (Oral): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Amphetamines: May increase analgesic effects of Opioid Agonists. Risk C: Monitor
Artemether and Lumefantrine: May increase serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor
Articaine: May increase CNS depressant effects of CNS Depressants. Management: Consider reducing the dose of articaine if possible when used in patients who are also receiving CNS depressants. Monitor for excessive CNS depressant effects with any combined use. Risk D: Consider Therapy Modification
Azelastine (Nasal): May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Benperidol: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Benperidol. Risk C: Monitor
Benperidol: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Benztropine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Benztropine. Risk C: Monitor
Benzylpenicilloyl Polylysine: Coadministration of Antihistamines and Benzylpenicilloyl Polylysine may alter diagnostic results. Management: Suspend systemic H1 antagonists for benzylpenicilloyl-polylysine skin testing and delay testing until systemic antihistaminic effects have dissipated. A histamine skin test may be used to assess persistent antihistaminic effects. Risk D: Consider Therapy Modification
Betahistine: Antihistamines may decrease therapeutic effects of Betahistine. Betahistine may decrease therapeutic effects of Antihistamines. Risk C: Monitor
Biperiden: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Biperiden. Risk C: Monitor
Blonanserin: CNS Depressants may increase CNS depressant effects of Blonanserin. Management: Use caution if coadministering blonanserin and CNS depressants; dose reduction of the other CNS depressant may be required. Strong CNS depressants should not be coadministered with blonanserin. Risk D: Consider Therapy Modification
Bornaprine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Bornaprine. Risk C: Monitor
Botulinum Toxin-Containing Products: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Brimonidine (Topical): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Bromopride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Bromperidol: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Buclizine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Buclizine. Risk C: Monitor
Buclizine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Buprenorphine: CNS Depressants may increase CNS depressant effects of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Risk D: Consider Therapy Modification
Buprenorphine: May decrease therapeutic effects of Opioid Agonists. Management: Seek alternatives to buprenorphine in patients receiving pure opioid agonists. If combined in certain pain management situations (eg, surgery), monitor for symptoms of therapeutic failure/high dose requirements or opioid withdrawal symptoms. Risk D: Consider Therapy Modification
BusPIRone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Cannabinoid-Containing Products: Agents with Clinically Relevant Anticholinergic Effects may increase tachycardic effects of Cannabinoid-Containing Products. Risk C: Monitor
Cannabinoid-Containing Products: CNS Depressants may increase CNS depressant effects of Cannabinoid-Containing Products. Risk C: Monitor
Certoparin: Antihistamines may increase therapeutic effects of Certoparin. Risk C: Monitor
Cetirizine (Systemic): May increase CNS depressant effects of CNS Depressants. Management: Consider avoiding this combination if possible. If required, monitor for excessive sedation or CNS depression, limit the dose and duration of combination therapy, and consider CNS depressant dose reductions. Risk D: Consider Therapy Modification
Chloral Hydrate/Chloral Betaine: CNS Depressants may increase CNS depressant effects of Chloral Hydrate/Chloral Betaine. Management: Consider alternatives to the use of chloral hydrate or chloral betaine and additional CNS depressants. If combined, consider a dose reduction of either agent and monitor closely for enhanced CNS depressive effects. Risk D: Consider Therapy Modification
Chlormethiazole: May increase CNS depressant effects of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Risk D: Consider Therapy Modification
Chlorphenesin Carbamate: May increase adverse/toxic effects of CNS Depressants. Risk C: Monitor
Cimetropium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Cimetropium. Risk X: Avoid
CloZAPine: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of CloZAPine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for signs and symptoms of gastrointestinal hypomotility and consider prophylactic laxative treatment. Risk D: Consider Therapy Modification
CYP2D6 Inhibitors (Moderate): May decrease therapeutic effects of Codeine. These CYP2D6 inhibitors may prevent the metabolic conversion of codeine to its active metabolite morphine. Risk C: Monitor
CYP2D6 Inhibitors (Strong): May decrease therapeutic effects of Codeine. These CYP2D6 inhibitors may prevent the metabolic conversion of codeine to its active metabolite morphine. Risk C: Monitor
CYP2D6 Inhibitors (Strong): May increase serum concentration of Chlorpheniramine. Risk C: Monitor
CYP3A4 Inducers (Moderate): May decrease active metabolite exposure of Codeine. Risk C: Monitor
CYP3A4 Inducers (Strong): May decrease active metabolite exposure of Codeine. Risk C: Monitor
CYP3A4 Inhibitors (Moderate): May increase active metabolite exposure of Codeine. Risk C: Monitor
CYP3A4 Inhibitors (Strong): May increase active metabolite exposure of Codeine. Risk C: Monitor
Daridorexant: May increase CNS depressant effects of CNS Depressants. Management: Dose reduction of daridorexant and/or any other CNS depressant may be necessary. Use of daridorexant with alcohol is not recommended, and the use of daridorexant with any other drug to treat insomnia is not recommended. Risk D: Consider Therapy Modification
Darifenacin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Darifenacin. Risk C: Monitor
Desmopressin: Opioid Agonists may increase hyponatremic effects of Desmopressin. Risk C: Monitor
DexmedeTOMIDine: CNS Depressants may increase CNS depressant effects of DexmedeTOMIDine. Management: Monitor for increased CNS depression during coadministration of dexmedetomidine and CNS depressants, and consider dose reductions of either agent to avoid excessive CNS depression. Risk D: Consider Therapy Modification
Dicyclomine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Dicyclomine. Risk C: Monitor
Difelikefalin: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Dihydralazine: CNS Depressants may increase hypotensive effects of Dihydralazine. Risk C: Monitor
Dimethindene (Topical): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Diuretics: Opioid Agonists may increase adverse/toxic effects of Diuretics. Opioid Agonists may decrease therapeutic effects of Diuretics. Risk C: Monitor
Dothiepin: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
DroNABinol: Agents with Clinically Relevant Anticholinergic Effects may increase tachycardic effects of DroNABinol. Risk X: Avoid
DroPERidol: May increase CNS depressant effects of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Risk D: Consider Therapy Modification
Eluxadoline: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of Eluxadoline. Risk X: Avoid
Eluxadoline: Opioid Agonists may increase constipating effects of Eluxadoline. Risk X: Avoid
Emedastine (Systemic): May increase CNS depressant effects of CNS Depressants. Management: Consider avoiding this combination if possible. If required, monitor for excessive sedation or CNS depression, limit the dose and duration of combination therapy, and consider CNS depressant dose reductions. Risk C: Monitor
Entacapone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Fesoterodine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Fesoterodine. Risk C: Monitor
Flunarizine: CNS Depressants may increase CNS depressant effects of Flunarizine. Risk X: Avoid
Flunitrazepam: CNS Depressants may increase CNS depressant effects of Flunitrazepam. Management: Reduce the dose of CNS depressants when combined with flunitrazepam and monitor patients for evidence of CNS depression (eg, sedation, respiratory depression). Use non-CNS depressant alternatives when available. Risk D: Consider Therapy Modification
Fosphenytoin-Phenytoin: Chlorpheniramine may increase serum concentration of Fosphenytoin-Phenytoin. Risk C: Monitor
Gastrointestinal Agents (Prokinetic): Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Gastrointestinal Agents (Prokinetic). Risk C: Monitor
Gastrointestinal Agents (Prokinetic): Opioid Agonists may decrease therapeutic effects of Gastrointestinal Agents (Prokinetic). Risk C: Monitor
Gepotidacin: May decrease anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Glucagon: Agents with Clinically Relevant Anticholinergic Effects may increase adverse/toxic effects of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Risk C: Monitor
Glycopyrrolate (Oral Inhalation): Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Glycopyrrolate (Oral Inhalation). Risk X: Avoid
Glycopyrrolate (Systemic): Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Glycopyrrolate (Systemic). Risk C: Monitor
Glycopyrronium (Topical): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Grapefruit Juice: May increase serum concentration of Codeine. Risk C: Monitor
Hyaluronidase: Antihistamines may decrease therapeutic effects of Hyaluronidase. Risk C: Monitor
HydrOXYzine: May increase CNS depressant effects of CNS Depressants. Management: Consider a decrease in the CNS depressant dose, as appropriate, when used together with hydroxyzine. Increase monitoring of signs/symptoms of CNS depression in any patient receiving hydroxyzine together with another CNS depressant. Risk D: Consider Therapy Modification
Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies): May decrease therapeutic effects of Opioid Agonists. Opioid Agonists may decrease therapeutic effects of Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies). Risk C: Monitor
Ipratropium (Nasal): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Ipratropium (Oral Inhalation): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Isoproterenol: Chlorpheniramine may increase therapeutic effects of Isoproterenol. Risk C: Monitor
Itopride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Itopride. Risk C: Monitor
Ixabepilone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Kava Kava: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Ketotifen (Systemic): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Kratom: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Lemborexant: May increase CNS depressant effects of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Risk D: Consider Therapy Modification
Levocetirizine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Levosulpiride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Levosulpiride. Risk X: Avoid
Lisuride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Lofexidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Loxapine: CNS Depressants may increase CNS depressant effects of Loxapine. Management: Consider reducing the dose of CNS depressants administered concomitantly with loxapine due to an increased risk of respiratory depression, sedation, hypotension, and syncope. Risk D: Consider Therapy Modification
Magnesium Sulfate: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Mavorixafor: May increase serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk X: Avoid
Melperone: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Mequitazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Metergoline: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Methotrimeprazine: CNS Depressants may increase CNS depressant effects of Methotrimeprazine. Methotrimeprazine may increase CNS depressant effects of CNS Depressants. Management: Reduce the usual dose of CNS depressants by 50% if starting methotrimeprazine until the dose of methotrimeprazine is stable. Monitor patient closely for evidence of CNS depression. Risk D: Consider Therapy Modification
Methscopolamine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Methscopolamine. Risk C: Monitor
Metoclopramide: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
MetyroSINE: CNS Depressants may increase sedative effects of MetyroSINE. Risk C: Monitor
Minocycline (Systemic): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Mirabegron: Agents with Clinically Relevant Anticholinergic Effects may increase adverse/toxic effects of Mirabegron. Risk C: Monitor
Monoamine Oxidase Inhibitors: May increase adverse/toxic effects of Codeine. Risk X: Avoid
Moxonidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Nabilone: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Nalfurafine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Nalfurafine: Opioid Agonists may increase adverse/toxic effects of Nalfurafine. Opioid Agonists may decrease therapeutic effects of Nalfurafine. Risk C: Monitor
Nalmefene: May decrease therapeutic effects of Opioid Agonists. Management: Avoid the concomitant use of oral nalmefene and opioid agonists. Discontinue oral nalmefene 1 week prior to any anticipated use of opioid agonists. If combined, larger doses of opioid agonists will likely be required. Risk D: Consider Therapy Modification
Naltrexone: May decrease therapeutic effects of Opioid Agonists. Management: Seek therapeutic alternatives to opioids. See full drug interaction monograph for detailed recommendations. Risk X: Avoid
Nefazodone: Opioid Agonists (metabolized by CYP3A4 and CYP2D6) may increase serotonergic effects of Nefazodone. This could result in serotonin syndrome. Nefazodone may increase serum concentration of Opioid Agonists (metabolized by CYP3A4 and CYP2D6). Management: Monitor for increased opioid effects, including fatal respiratory depression, when these agents are combined and consider opioid dose reductions until stable drug effects are achieved. Additionally, monitor for serotonin syndrome/serotonin toxicity. Risk C: Monitor
Nitroglycerin: Agents with Clinically Relevant Anticholinergic Effects may decrease absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Risk C: Monitor
Noscapine: CNS Depressants may increase adverse/toxic effects of Noscapine. Risk X: Avoid
Olopatadine (Nasal): May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Opicapone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Opioids (Mixed Agonist / Antagonist): May decrease analgesic effects of Opioid Agonists. Management: Seek alternatives to mixed agonist/antagonist opioids in patients receiving pure opioid agonists, and monitor for symptoms of therapeutic failure/high dose requirements (or withdrawal in opioid-dependent patients) if patients receive these combinations. Risk X: Avoid
Opipramol: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Opipramol: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Orphenadrine: CNS Depressants may increase CNS depressant effects of Orphenadrine. Risk X: Avoid
Oxatomide: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Oxomemazine: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Oxybate Salt Products: CNS Depressants may increase CNS depressant effects of Oxybate Salt Products. Management: Consider alternatives to this combination when possible. If combined, dose reduction or discontinuation of one or more CNS depressants (including the oxybate salt product) should be considered. Interrupt oxybate salt treatment during short-term opioid use Risk D: Consider Therapy Modification
OxyBUTYnin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of OxyBUTYnin. Risk C: Monitor
OxyCODONE: CNS Depressants may increase CNS depressant effects of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Risk D: Consider Therapy Modification
Paraldehyde: CNS Depressants may increase CNS depressant effects of Paraldehyde. Risk X: Avoid
Peginterferon Alfa-2b: May decrease serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Peginterferon Alfa-2b may increase serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor
Pegvisomant: Opioid Agonists may decrease therapeutic effects of Pegvisomant. Risk C: Monitor
Perazine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Periciazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Perphenazine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Perphenazine. Risk C: Monitor
PHENobarbital: May increase CNS depressant effects of Codeine. PHENobarbital may decrease serum concentration of Codeine. Management: Avoid use of codeine and phenobarbital when possible. Monitor for respiratory depression/sedation. Because phenobarbital is also a moderate CYP3A4 inducer, monitor for decreased codeine efficacy and withdrawal if combined. Risk D: Consider Therapy Modification
Pipamperone: May increase adverse/toxic effects of CNS Depressants. Risk C: Monitor
Piribedil: CNS Depressants may increase CNS depressant effects of Piribedil. Risk C: Monitor
Pitolisant: Antihistamines may decrease therapeutic effects of Pitolisant. Risk X: Avoid
Potassium Chloride: Agents with Clinically Relevant Anticholinergic Effects may increase ulcerogenic effects of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Risk X: Avoid
Potassium Citrate: Agents with Clinically Relevant Anticholinergic Effects may increase ulcerogenic effects of Potassium Citrate. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium citrate. Risk X: Avoid
Pramipexole: CNS Depressants may increase sedative effects of Pramipexole. Risk C: Monitor
Pramlintide: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. These effects are specific to the GI tract. Risk X: Avoid
Primidone: May increase CNS depressant effects of Codeine. Primidone may decrease serum concentration of Codeine. Management: Avoid use of codeine and primidone when possible. Monitor for respiratory depression/sedation. Because primidone is also a strong CYP3A4 inducer, monitor for decreased codeine efficacy and withdrawal if combined. Risk D: Consider Therapy Modification
Procarbazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Propantheline: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Propantheline. Risk C: Monitor
Propiverine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. 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
QuiNIDine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Ramosetron: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of Ramosetron. Risk C: Monitor
Ramosetron: Opioid Agonists may increase constipating effects of Ramosetron. Risk C: Monitor
Revefenacin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Revefenacin. Risk X: Avoid
Rilmenidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Rivastigmine: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Rivastigmine. Rivastigmine may decrease therapeutic effects of Agents with Clinically Relevant Anticholinergic Effects. Management: Use of rivastigmine with an anticholinergic agent is not recommended unless clinically necessary. If the combination is necessary, monitor for reduced anticholinergic effects. Risk D: Consider Therapy Modification
Ropeginterferon Alfa-2b: CNS Depressants may increase adverse/toxic effects of Ropeginterferon Alfa-2b. Specifically, the risk of neuropsychiatric adverse effects may be increased. Management: Avoid coadministration of ropeginterferon alfa-2b and other CNS depressants. If this combination cannot be avoided, monitor patients for neuropsychiatric adverse effects (eg, depression, suicidal ideation, aggression, mania). Risk D: Consider Therapy Modification
ROPINIRole: CNS Depressants may increase sedative effects of ROPINIRole. Risk C: Monitor
Rotigotine: CNS Depressants may increase sedative effects of Rotigotine. Risk C: Monitor
Samidorphan: May decrease therapeutic effects of Opioid Agonists. Risk X: Avoid
Secretin: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Secretin. Management: Avoid concomitant use of anticholinergic agents and secretin. Discontinue anticholinergic agents at least 5 half-lives prior to administration of secretin. Risk D: Consider Therapy Modification
Serotonergic Agents (High Risk): Opioid Agonists (metabolized by CYP3A4 and CYP2D6) may increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Sincalide: Drugs that Affect Gallbladder Function may decrease therapeutic effects of Sincalide. Management: Consider discontinuing drugs that may affect gallbladder motility prior to the use of sincalide to stimulate gallbladder contraction. Risk D: Consider Therapy Modification
Sofpironium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Sofpironium. Risk X: Avoid
Somatostatin Analogs: May decrease active metabolite exposure of Codeine. Specifically, the concentrations of the active metabolite morphine may be reduced. Risk C: Monitor
Succinylcholine: May increase bradycardic effects of Opioid Agonists. Risk C: Monitor
Suvorexant: CNS Depressants may increase CNS depressant effects of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Risk D: Consider Therapy Modification
Thalidomide: CNS Depressants may increase CNS depressant effects of Thalidomide. Risk X: Avoid
Thiazide and Thiazide-Like Diuretics: Agents with Clinically Relevant Anticholinergic Effects may increase serum concentration of Thiazide and Thiazide-Like Diuretics. Risk C: Monitor
Tiapride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Tiapride. Risk C: Monitor
Tilidine: May increase therapeutic effects of Opioid Agonists. Risk X: Avoid
Tiotropium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Tiotropium. Risk X: Avoid
Tolterodine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Tolterodine. Risk C: Monitor
Tranylcypromine: May increase anticholinergic effects of Antihistamines, First Generation. Risk X: Avoid
Trospium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Trospium. Risk C: Monitor
Umeclidinium: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Valerian: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Zolpidem: CNS Depressants may increase CNS depressant effects of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Risk D: Consider Therapy Modification
Zuranolone: May increase CNS depressant effects of CNS Depressants. Management: Consider alternatives to the use of zuranolone with other CNS depressants or alcohol. If combined, consider a zuranolone dose reduction and monitor patients closely for increased CNS depressant effects. Risk D: Consider Therapy Modification
Long-term opioid use may cause secondary hypogonadism, which may lead to sexual dysfunction and infertility (Brennan 2013).
[US Boxed Warning]: Use is not recommended in pregnant women. Prolonged use of opioids during pregnancy can cause neonatal withdrawal syndrome, which may be life-threatening if not recognized and treated according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available.
See individual agents for additional information.
Codeine and chlorpheniramine are present in breast milk. Due to the potential for serious adverse reactions in the breastfed infant, breastfeeding is not recommended by the manufacturer. See individual agents.
Relief of symptoms; respiratory and mental status; bowel function; signs/symptoms of substance use disorder, abuse, or misuse.
Codeine: Binds to opioid receptors in the CNS, causing inhibition of ascending pain pathways, altering the perception of and response to pain; causes cough suppression by direct central action in the medulla; produces generalized CNS depression.
Chlorpheniramine: H1 receptor antagonist that also possesses anticholinergic and sedative activity. It prevents released histamine from dilating capillaries and causing edema of the respiratory mucosa.
See individual agents.
