(mi NOKS i dil)
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Generic: 2.5 mg, 10 mg
- Vasodilator, Direct-Acting
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
~90%, primarily via glucuronidation
Urine (12% as unchanged drug)
Onset of Action
Hypotensive: ~30 minutes; Peak effect: 2 to 3 hours
Duration of Action
Up to 2 to 5 days
3.5 to 4.2 hours
Use: Labeled Indications
Hypertension: 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. Use in milder degrees of hypertension is not recommended because the benefit-risk ratio in such patients has not been defined.
Note: According to the Eighth Joint National Committee (JNC 8) guidelines, minoxidil is not recommended for the initial treatment of hypertension (James, 2013).
Hypersensitivity to minoxidil or any component of the formulation; pheochromocytoma
Canadian labeling: Additional contraindications (not in U.S. labeling): Pulmonary hypertension associated with mitral stenosis; severe hepatic impairment
Hypertension: Oral: Initial: 5 mg once daily, increase dose gradually in single or divided doses every 3 days or more (or every 6 hours with careful monitoring if rapid management required) (maximum: 100 mg daily); usual dosage range: 10 to 40 mg (manufacturer's labeling); others have recommended 5 to 10 mg daily (ASH/ISH [Weber, 2014])
Note: Dosage adjustment is needed when added to concomitant therapy. If supine diastolic pressure reduced <30 mm Hg, administer dose once daily; if supine diastolic pressure reduced >30 mm Hg, administer dose in 2 divided equal parts
Dosage adjustment with concomitant therapy: Canadian labeling: Consider initiating minoxidil at a reduced dose in patients receiving strong UGT inhibitors (eg, valproic acid, atazanavir, probenecid)
Hypertension: Initial: 2.5 mg once daily; increase gradually (ASH/ISH [Weber, 2014])
Children <12 years: Oral: Initial: 0.2 mg/kg once daily; maximum daily initial dose: 5 mg daily; titrate gradually to effect every 3 days; usual dosage: 0.25 to 1 mg/kg/day in 1 to 3 divided doses (NHLBI, 2005); maximum daily dose: 50 mg daily
Children ≥12 years and Adolescents: Refer to adult dosing
Dosing: Renal Impairment
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.
Dosing: Hepatic Impairment
US labeling: There are no dosage adjustments provided in the manufacturer's labeling.
Mild or moderate impairment: There are no specific dosage adjustments provided in the manufacturer's labeling; however, a reduced dosage should be considered.
Severe impairment: Use is contraindicated.
Store between 20°C and 25°C (68°F and 77°F).
Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, blood pressure lowering medications should be withheld for 24 hours prior to amifostine administration. If blood pressure lowering therapy cannot be withheld, amifostine should not be administered. Consider therapy modification
Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy
Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Monitor therapy
Atazanavir: May increase the serum concentration of Minoxidil (Systemic). Monitor therapy
Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
CycloSPORINE (Systemic): May enhance the adverse/toxic effect of Minoxidil (Systemic). Severe hypertrichosis has been reported. Monitor therapy
Dapoxetine: May enhance the orthostatic hypotensive effect of Minoxidil (Systemic). Monitor therapy
Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Monitor therapy
Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy
Herbs (Hypotensive Properties): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Monitor therapy
Levodopa: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa. Monitor therapy
Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy
Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Monitor therapy
Obinutuzumab: May enhance the hypotensive effect 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. Consider therapy modification
Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Probenecid: May increase the serum concentration of Minoxidil (Systemic). Monitor therapy
Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy
Valproate Products: May increase the serum concentration of Minoxidil (Systemic). Monitor therapy
Yohimbine: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy
Frequency not always reported.
Cardiovascular: ECG changes (T-wave changes 60%), edema (reversible, 7% to 10%), pericardial effusion (occasionally with tamponade, 3%), angina pectoris, cardiac failure, pericarditis, tachycardia
Dermatologic: Hypertrichosis (80%), bullous rash (rare), skin rash, Stevens-Johnson syndrome (rare), toxic epidermal necrolysis
Endocrine & metabolic: Breast tenderness (rare; <1%), sodium retention, water retention, weight gain
Gastrointestinal: Nausea, vomiting
Hematologic & oncologic: Decreased hematocrit (transient, hemodilution), decreased red blood cells (transient, hemodilution), hemoglobin (transient, hemodilution), leukopenia (rare), thrombocytopenia (rare)
Hepatic: Ascites, increased serum alkaline phosphatase
Renal: Increased blood urea nitrogen (transient), increased serum creatinine (transient)
Respiratory: Pulmonary edema (Lee 2011)
<1% (Limited to important or life-threatening): Breast tenderness (rare)
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.
• Acute myocardial infarct (MI): Avoid use for a month after acute MI. 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).
• 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.
Concurrent drug therapy issues:
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
• Elderly: Use with caution in the elderly; initiate at the low end of the dosage range and monitor closely.
• 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.
Blood pressure, standing and sitting/supine; signs/symptoms of pericardial effusion; fluid and electrolyte balance and body weight should be monitored. Any tests that are abnormal at the time of initiation (including, renal function tests, ECG, echocardiogram, chest x-ray) should be repeated initially every 1 to 3 months then every 6 to 12 months once stable.
Pregnancy Risk Factor
Adverse events were observed in some animal studies. Neonatal hypertrichosis has been reported following exposure to minoxidil during pregnancy.
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience hair growth, vomiting, or nausea. Have patient report immediately to prescriber shortness of breath, angina, arm pain, shoulder pain, tachycardia, dizziness, passing out, arrhythmia, heartburn, hearing impairment, vision changes, weight gain, or swelling of arms or legs (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
More about minoxidil
- Other brands: Loniten