Minoxidil is an antihypertensive vasodilator medication and is used to treat hair loss. It is available as a generic medication and over the counter for the treatment of androgenic alopecia, a form of hair loss, in people.
Molecular Structure |
Class of Drug |
Antihypertensive, vasodilator, hair growth stimulator.
Mechanism of Action |
Causes arteriolar smooth muscle relaxation, resulting in decreased BP, increased peripheral resistance. Stimulates hair follicles by increasing blood flow to skin.
Indications / Dosage / Route |
Routes of Administration: Oral, topical..
Condition: Hypertension (combination, usually with diuretic and (β blocker)
Dose: Adults, children >12 years: Initial: PO 5 mg/d. Slowly increase dose q3d to optimum BP response. Maintenance: 10-40 mg/d. Maximum: 100 mg/d.
Children: <12 years: 0.1-0.2 mg/kg/d as single dose (maximum: 5 mg). Gradually increase q3d to 0.25-1 mg/kg/d in single or divided doses (maximum 50 mg/d).
Condition: Topical male and female pattern baldness
Dose: 1 ml (2 or 5% solution) bid to area with loss of hair
Adjustment of Dosage |
Kidney disease: Reduce dose by one-third usual in renal failure.
Liver disease: None.
Elderly: Initial dose reduced to 2.5 mg daily. Slow dosage increases.
Pediatric: See above.
| Onset of Action | Peak Effect | Duration |
| 30 min | 2-3 h | 2-5 d |
Food and Drug Interactions |
Food: May be taken with or without food.
Pregnancy: Category C.
Lactation: Appears in breast milk. Potentially toxic to infant. Avoid breastfeeding.
Contraindications: Hypersensitivity to minoxidil, pheochromocytoma, MI (within 1 month), dissecting aortic aneurysm.
Warnings / Precautions |
> Use with caution in patients with coronary artery disease, renal disease(severe), pulmonary hypertension, CHF.
> Prior to discontinuation, consult treating physician.
> To minimize possible photosensitivity reaction, apply adequate sunscreen and use proper covering when exposed to strong sunlight.
Clinically Important Drug Interactions |
> Drugs that increase effects/toxicity of minoxidil: guanethidine, diuretics, other antihypertensives.
> Drugs that decrease effects/toxicity of minoxidil: NSAIDs.
Adverse Reactions |
> Common: Edema, tachycardia, breast tenderness, weight gain, hypertrichosis.
> Serious: predisposition to CHF, pericardial effusion, Stevens Johnson syndrome, fluid and electrolyte disturbance, angina, bone marrow suppression.
Parameters to Monitor |
> BP and pulse for orthostasis, checking supine, seated, and standing BPs. Significant changes, eg, heart rate increase >20 beats/min, probably require reduction of dosage.
> Intake of fluids and urinary and other fluid output to minimize renal toxicity. Closely monitor electrolyte levels.
> Signs of CHF.
> Signs and symptoms of Stevens-Johnson syndrome.
Advice to Patient |
> Do not take magnesium-containing antacids.
Further Useful Info |
> Minoxidil should be given along with a diuretic unless the patient is on hemodialysis.
> Use should be limited to those patients who do not respond to maximum doses of diuretics and to other antihypertensive agents.
> Minoxidil should be administered under close supervision by the treating physician.
> A P blocker is generally given concomitantly to prevent tachycardia.
> Oral and topical forms of minoxidil have been used to treat male pattern baldness. Minoxidil stimulates resting hair follicles and increases cutaneous blood flow via its vasodilatory properties.
