Minoxidil may produce serious adverse effects. It can cause pericardial effusion, occasionally progressing to tamponade, and it can exacerbate angina pectoris. Reserve for hypertensive patients who do not respond adequately to maximum therapeutic doses of a diuretic and 2 other antihypertensive agents.
In experimental animals, minoxidil caused several kinds of myocardial lesions and other adverse cardiac effects.
Administer under close supervision, usually concomitantly with therapeutic doses of a beta-adrenergic blocking agent, to prevent tachycardia and increased myocardial workload. Usually, it must be given with a diuretic, frequently one acting in the ascending limb of the loop of Henle to prevent serious fluid accumulation. When first administering minoxidil, hospitalize and monitor patients with malignant hypertension and those already receiving guanethidine to avoid too rapid or large orthostatic decreases in blood pressure.
Hypertension (alternate agent):
Acute severe hypertension with significant but not life-threatening symptoms (eg, severe headache, vomiting but no seizures):
Children and Adolescents: Oral: Initial: 0.1 to 0.2 mg/kg/dose; may repeat every 8 to 12 hours; maximum dose: 10 mg/dose (Ref). Note: In situations where rapid blood pressure management required, may increase dose after 6 hours with careful monitoring.
Chronic hypertension:
Note: Recommended for use in refractory hypertension with persistent symptoms or target organ damage despite maximal treatment with a diuretic and 2 antihypertensive agents.
Children <12 years: Oral: Initial: 0.2 mg/kg/dose once daily; maximum initial dose: 5 mg/dose; titrate to effect, may increase daily dose by 50% to 100% (eg, 0.1 to 0.2 mg/kg/day) every 3 days; may need to divide doses 1 to 3 times daily; usual daily dose: 0.25 to 1 mg/kg/day in 1 to 3 divided doses; maximum daily dose: 50 mg/day (Ref). Note: In situations where rapid blood pressure management required, may increase dose after 6 hours with careful monitoring.
Children ≥12 years and Adolescents: Oral: Initial: 5 mg once daily; titrate to effect; may increase every 3 days by doubling daily dose (10 mg/day, 20 mg/day, and then 40 mg/day); may need to divide doses 1 to 3 times daily; usual daily dose: 10 to 40 mg/day in 1 to 3 divided doses; maximum daily dose: 100 mg/day (Ref). Note: In situations where rapid blood pressure management required, may increase dose after 6 hours with careful monitoring.
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 and Adolescents: Oral: There are no specific dosage recommendations provided in the manufacturer's labeling; however, the manufacturer suggests that patients with renal failure may require a dosage reduction.
Hemodialysis: Dialyzable. Children and Adolescents: Oral: There are no specific dosage recommendations provided in the manufacturer's labeling; however, the manufacturer suggests that patients receiving dialysis may require a dosage reduction.
Children and Adolescents: There are no dosage adjustments provided in the manufacturer's labeling; use with caution and titrate gradually (minoxidil AUC increased 50% and its clearance decreased in mildly cirrhotic adult patients (Ref)).
(For additional information see "Minoxidil (systemic): Drug information")
Hypertension (alternative agent) (adjunctive agent):
Note: Before prescribing, consider referral to a clinician with expertise in managing hypertension. Reserve for patients with resistant hypertension who do not respond adequately to an optimized 4-drug regimen, ideally consisting of a thiazide-like diuretic (eg, chlorthalidone) and a mineralocorticoid-receptor antagonist (eg, spironolactone). Use in combination with a beta-blocker to prevent reflex tachycardia. Fluid retention may occur and may require additional diuretic therapy (Ref).
Oral: Initial: 5 mg once daily, increase dose gradually in intervals of ≥3 days; usual effective dose: 10 to 40 mg/day in 1 to 3 divided doses; maximum dose: 100 mg/day in 1 to 3 divided doses. During therapy, if supine diastolic pressure is reduced <30 mm Hg, administer total daily dose once daily; if supine diastolic pressure is reduced >30 mm Hg, administer 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.
There are no specific dosage recommendations provided in the manufacturer's labeling; however, the manufacturer suggests that patients with renal failure and/or receiving dialysis may require a dosage reduction.
There are no dosage adjustments provided in the manufacturer's labeling; use with caution and titrate gradually (minoxidil AUC increased 50% and its clearance decreased in mildly cirrhotic patients (Ref)).
Minoxidil is associated with fluid retention and subsequent local and generalized edema, including pitting edema, in adult and pediatric patients (Ref). Patients may experience weight gain due to fluid retention (Ref). Fluid retention is reversible and may be a reason for treatment discontinuation or initiation of diuretic therapy (Ref).
Mechanism: Dose-related (Ref); related to the pharmacologic action (ie, increased sodium and water reabsorption) (Ref).
Onset: Varied. Fluid retention may occur within weeks of treatment initiation (Ref); one trial investigating the use of oral minoxidil for the treatment of hair loss (n=1404) found a mean onset of fluid retention of 60 days (range: 15 to 360 days) (Ref)
Risk factors:
• Heart failure or cardiomyopathy (Ref)
Topical minoxidil is used therapeutically for the treatment of alopecia androgenetica; however, hypertrichosis or hair growth in undesirable locations may occur with use of minoxidil for any indication in both adult and pediatric patients (Ref). Excessive hair growth can occur at any location on the body and may lead to treatment discontinuation (Ref). Hypertrichosis is reversible upon discontinuation (Ref); some patients may tolerate or choose to address unwanted hair growth with hair removal techniques as opposed to discontinuing treatment (Ref).
Mechanism: Dose-related (Ref); related to the pharmacologic action (eg, vasodilation leading to increased cutaneous blood flow and subsequent hair growth (Ref)).
Onset: Intermediate to delayed (Ref); one trial investigating the use of oral minoxidil for the treatment of hair loss (n=1404) found a mean onset of hypertrichosis of 60 days (range: 14 to 450 days) (Ref).
Risk factors:
• Higher doses (eg, >1 mg per day (Ref))
• Use of oral minoxidil as compared to topical minoxidil (Ref)
Minoxidil may cause orthostatic hypotension (Ref). Some patients require intervention (eg, increased dietary sodium) or treatment discontinuation due to orthostatic hypotension (Ref).
Mechanism: Dose-related; related to the pharmacologic action (eg, vasodilation)
Onset: Rapid to intermediate; one trial investigating the use of oral minoxidil for the treatment of hair loss (n=1404) found a mean onset of lightheadedness (possibly due to orthostatic hypotension) of 5 days (range: 1 to 20 days) (Ref)
Risk factors:
• Concomitant administration of other antihypertensive agents
The use of minoxidil can result in pericarditis or pericardial effusion that may progress to cardiac tamponade in adult and pediatric patients (Ref); pericardial effusion is reversible following discontinuation of minoxidil and may recur with reinitiation of therapy (Ref).
Mechanism: Not clearly established. May be non–dose-related (idiosyncratic) (Ref) or dose-dependent and related to the pharmacologic action (ie, increased sodium and water reabsorption) (Ref)
Onset: Varied; may occur at any time during treatment (Ref), especially following treatment initiation or dose titration (Ref).
Risk factors:
• Patients with kidney impairment, including patients undergoing hemodialysis (Ref). Clinicians should note that pericardial effusion may also occur in patients without a history of impaired kidney function (Ref).
• Heart failure
The use of minoxidil is associated with reflex tachycardia (Ref); the increase in heart rate may increase oxygen demand and precipitate or exacerbate myocardial ischemia and resultant angina. Patients may require intervention (eg, beta-blockade) or treatment discontinuation (Ref).
Mechanism: Dose-related; related to the pharmacologic action (eg, reflex tachycardia secondary to vasodilation (Ref))
Onset: Rapid to intermediate (Ref); one trial investigating the use of oral minoxidil for the treatment of hair loss (n=1404) found a mean onset of tachycardia of 1 day (range: 0 to 7 days) (Ref)
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Cardiovascular: Abnormal T waves on ECG (~60%)
Dermatologic: Hypertrichosis (~80%)
1% to 10%: Cardiovascular: Edema (7% to 10%), pericardial effusion (~3%; including cardiac tamponade)
<1%:
Genitourinary: Breast tenderness
Hypersensitivity: Hypersensitivity reaction
Frequency not defined:
Cardiovascular: Exacerbation of angina pectoris, increased heart rate, increased plasma volume
Hepatic: Increased serum alkaline phosphatase
Renal: Increased blood urea nitrogen, increased serum creatinine
Postmarketing:
Cardiovascular: Pericarditis
Dermatologic: Bullous rash, skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis
Gastrointestinal: Nausea, vomiting
Hematologic & oncologic: Leukopenia, thrombocytopenia
Hepatic: Ascites (McNay 1983)
Respiratory: Pulmonary edema (Dargie 1977; Lee 2011)
Hypersensitivity to minoxidil or any component of the formulation; pheochromocytoma
Canadian labeling: Additional contraindications (not in US labeling): Pulmonary hypertension associated with mitral stenosis; severe hepatic impairment
Concerns related to adverse effects:
• Fluid retention: May cause salt and water retention; administer with a diuretic, preferably a loop diuretic (eg, furosemide) to prevent fluid retention and subsequent local and generalized edema. Use with extreme caution in patients with heart failure.
• Pericardial effusion/tamponade: [US Boxed Warning]: May cause pericarditis and pericardial effusion that may progress to tamponade; patients with renal impairment not on dialysis may be at higher risk. Use with caution in patients with heart failure; observe patients closely. If effusion persists, consider discontinuation of minoxidil.
• Rapid blood pressure control: Rapid control of blood pressure in patients with severe hypertension can lead to syncope, cerebrovascular accidents, MI, and/or ischemia of other special sense organs resulting in decrease or loss of vision or hearing. Patients with compromised circulation or cryoglobulinemia may also suffer ischemic episodes of the affected organs.
• Sinus tachycardia: [US Boxed Warning]: May increase oxygen demand and exacerbate angina pectoris; concomitant use with a beta-blocker (if no contraindication exists) may help reduce the effect. Use with caution in patients with ischemic heart disease.
Disease-related concerns:
• Acute myocardial infarct (MI): Avoid use for a month after acute MI as use may increase oxygen demand due to reflex tachycardia. Use with extreme caution; ensure patient is receiving a beta blocker prior to initiation.
• Heart failure: Compared to placebo minoxidil increased the frequency of clinical events, including increased need for diuretics, angina, ventricular arrhythmias, worsening heart failure and death (Franciosa 1984). In a scientific statement from the American Heart Association, minoxidil has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: moderate) (AHA [Page 2016]).
• Renal impairment: Use with caution in patients with significant renal impairment; renal failure and dialysis patients may require a smaller dose. Monitor closely to prevent exacerbation of renal failure.
Special populations:
• Older adult: Use with caution in the elderly; initiate at the low end of the dosage range and monitor closely.
Other warnings/precautions:
• Appropriate use: [US Boxed Warning]: Maximum therapeutic doses of a diuretic and two other antihypertensives should be used before this drug is ever added. Should be given with a diuretic to minimize fluid gain and a beta-blocker (if no contraindications) to prevent tachycardia and increased myocardial workload. Patients with malignant hypertension and those already receiving guanethidine should be hospitalized with close medical supervision to ensure blood pressure is reducing and to prevent too rapid of a reduction in blood pressure.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 2.5 mg, 10 mg
Yes
Tablets (Minoxidil Oral)
2.5 mg (per each): $0.59 - $0.78
10 mg (per each): $1.29 - $1.69
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:
Loniten: 2.5 mg, 10 mg
Oral: May be administered without regard to food
Store between 20°C and 25°C (68°F and 77°F).
Treatment of hypertension that is symptomatic or associated with target organ damage and is not manageable with maximum therapeutic doses of a diuretic plus 2 other antihypertensives (FDA approved in children, adolescents, and adults). Note: Not recommended for use in milder degrees of hypertension; benefit-risk ratio in such patients has not been defined (AAP [Flynn 2017]; manufacturer's labeling).
Loniten [CAN] may be confused with Lipitor
Minoxidil may be confused with metOLazone, midodrine, Minipress, Minocin, Monopril, Minoxidin (dietary supplement), Noxafil
Noxidil [Thailand] may be confused with Noxafil brand name for posaconazole [US and multiple international markets]
None known.
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.
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
Alfuzosin: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Amifostine: Blood Pressure Lowering Agents may increase hypotensive effects of Amifostine. Management: When used at chemotherapy doses, hold blood pressure lowering medications for 24 hours before amifostine administration. If blood pressure lowering therapy cannot be held, do not administer amifostine. Use caution with radiotherapy doses of amifostine. Risk D: Consider Therapy Modification
Amphetamines: May decrease antihypertensive effects of Antihypertensive Agents. Risk C: Monitor
Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may increase hypotensive effects of Antipsychotic Agents (Second Generation [Atypical]). Risk C: Monitor
Arginine: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Barbiturates: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Benperidol: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Brigatinib: May decrease antihypertensive effects of Antihypertensive Agents. Brigatinib may increase bradycardic effects of Antihypertensive Agents. Risk C: Monitor
Brimonidine (Topical): May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Bromperidol: May decrease hypotensive effects of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may increase hypotensive effects of Bromperidol. Risk X: Avoid
CycloSPORINE (Systemic): May increase adverse/toxic effects of Minoxidil (Systemic). Severe hypertrichosis has been reported with this combination. Risk C: Monitor
Dapoxetine: May increase orthostatic hypotensive effects of Minoxidil (Systemic). Risk C: Monitor
Dexmethylphenidate: May decrease therapeutic effects of Antihypertensive Agents. Risk C: Monitor
Diazoxide: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
DULoxetine: Blood Pressure Lowering Agents may increase hypotensive effects of DULoxetine. Risk C: Monitor
Flunarizine: May increase therapeutic effects of Antihypertensive Agents. Risk C: Monitor
Guanethidine: May increase hypotensive effects of Minoxidil (Systemic). Management: When possible, discontinue guanethidine prior to initiation of minoxidil due to a risk of severe orthostasis and hypotension. If combined, minoxidil therapy should be initiated in the hospital, with close monitoring of blood pressure. Risk D: Consider Therapy Modification
Herbal Products with Blood Pressure Increasing Effects: May decrease antihypertensive effects of Antihypertensive Agents. Risk C: Monitor
Herbal Products with Blood Pressure Lowering Effects: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Hypotension-Associated Agents: Blood Pressure Lowering Agents may increase hypotensive effects of Hypotension-Associated Agents. Risk C: Monitor
Iloperidone: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Indoramin: May increase hypotensive effects of Antihypertensive Agents. Risk C: Monitor
Isocarboxazid: May increase antihypertensive effects of Antihypertensive Agents. Risk X: Avoid
Levodopa-Foslevodopa: Blood Pressure Lowering Agents may increase hypotensive effects of Levodopa-Foslevodopa. Risk C: Monitor
Loop Diuretics: May increase hypotensive effects of Antihypertensive Agents. Risk C: Monitor
Lormetazepam: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Metergoline: May decrease antihypertensive effects of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may increase orthostatic hypotensive effects of Metergoline. Risk C: Monitor
Methylphenidate: May decrease antihypertensive effects of Antihypertensive Agents. Risk C: Monitor
Molsidomine: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Naftopidil: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Nicergoline: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Nicorandil: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Nitroprusside: Blood Pressure Lowering Agents may increase hypotensive effects of Nitroprusside. Risk C: Monitor
Obinutuzumab: May increase hypotensive effects of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Risk D: Consider Therapy Modification
Pentoxifylline: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Perazine: May increase hypotensive effects of Antihypertensive Agents. Risk C: Monitor
Pholcodine: Blood Pressure Lowering Agents may increase hypotensive effects of Pholcodine. Risk C: Monitor
Phosphodiesterase 5 Inhibitors: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Prazosin: Antihypertensive Agents may increase hypotensive effects of Prazosin. Risk C: Monitor
Prostacyclin Analogues: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Quinagolide: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Silodosin: May increase hypotensive effects of Blood Pressure Lowering Agents. Risk C: Monitor
Terazosin: Antihypertensive Agents may increase hypotensive effects of Terazosin. Risk C: Monitor
Urapidil: Antihypertensive Agents may increase hypotensive effects of Urapidil. Risk C: Monitor
Adverse events were observed in some animal studies. Neonatal hypertrichosis has been reported following exposure to minoxidil during pregnancy.
Blood pressure, standing and sitting/supine; signs/symptoms of pericardial effusion; fluid and electrolyte balance, heart rate, urine output, and body weight should be monitored. Any tests that are abnormal at the time of initiation (including urinalysis, renal function tests, CBC, ECG, echocardiogram, chest x-ray) should be repeated every 1 to 3 months until stabilized, then every 6 to 12 months.
Produces vasodilation by directly relaxing arteriolar smooth muscle, with little effect on veins; effects may be mediated by cyclic AMP; stimulation of hair growth is secondary to vasodilation, increased cutaneous blood flow and stimulation of resting hair follicles
Onset of action: Hypotensive: ~30 minutes
Peak effect: 2 to 3 hours
Duration: Up to 2 to 5 days
Protein binding: None
Metabolism: ~90%, primarily via glucuronidation
Bioavailability: 90%
Half-life elimination: 3.5 to 4.2 hours
Excretion: Urine (12% as unchanged)