Minoxidil


Generic Medicine Info
Indications and Dosage
Oral
Severe hypertension unresponsive to standard therapy
Adult: In conjunction w/ a β-blocker or methyldopa, and a diuretic: Initially, 5 mg daily, gradually increase at intervals of at least 3 days to 40 mg or 50 mg as a single or in 2 divided doses daily depending on response. Max: 100 mg daily. For rapid control of BP: Dose increments of 5 mg 6 hrly may be given w/ careful monitoring.
Elderly: Initially, 2.5 mg daily, increase gradually.
Child: ≤12 yr In conjunction w/ a β-blocker or methyldopa, and a diuretic: Initially, 200 mcg/kg daily in 1 or 2 divided doses w/ increments of 100-200 mcg/kg at intervals of at least 3 days according to response. Max: 1 mg/kg or 50 mg daily.

Topical/Cutaneous
Male pattern baldness
Adult: Male: As 2% or 5% soln: Apply 1 mL to the scalp bid. As 5% foam or aerosol: Apply ½ capful to the scalp bid. Female: As 2% soln: Apply 1 mL to the scalp bid. As 5% foam or aerosol: Apply ½ capful to the scalp once daily.
Renal Impairment
Oral:
Initiate at smaller doses or at longer dosage intervals.
Administration
May be taken with or without food.
Contraindications
Phaeochromocytoma. Topical: Patient w/ treated or untreated HTN, scalp abnormality (e.g. psoriasis, sunburn), shaved scalp.
Special Precautions
Patient w/ pulmonary HTN, angina pectoris, chronic heart failure, recent MI. Renal impairment. Elderly, childn. Pregnancy and lactation.
Adverse Reactions
Reflex tachycardia, fluid retention, changes in ECG, hypertrichosis, pericardial effusion and tamponade, pericarditis, exacerbation of angina pectoris, headache, nausea, gynaecomastia, breast tenderness, polymenorrhoea, allergic rashes, Stevens-Johnson syndrome. Rarely, thrombocytopenia and leucopenia. Topical: Contact dermatitis, pruritus, local burning, flushing, changes in hair colour or texture.
Monitoring Parameters
Monitor BP, fluid and electrolytes, body wt, signs/symptoms of pericardial effusion, renal function.
Overdosage
Symptoms: Exaggerated hypotension. Management: Admin IV normal saline. Phenylephrine, angiotensin II and vasopressin may be given if inadequate perfusion of a vital organ is evident.
Drug Interactions
Additive effect w/ other hypotensive drugs. Risk of orthostatic hypotension w/ sympathetic blocking drugs (e.g. guanethidine). Topical: Enhanced absorption w/ other topical medical preparations (e.g. corticosteroids, retinoids or occlusive ointment bases).
Action
Description:
Mechanism of Action: Minoxidil reduces elevated systolic and diastolic BP by decreasing peripheral vascular resistance via vasodilation. Applied topically, it stimulates hair growth secondary to vasodilation, increases cutaneous blood flow and stimulates resting hair follicles.
Onset: Approx 30 min (oral).
Duration: Approx 3 days (oral).
Pharmacokinetics:
Absorption: Approx 90% is absorbed from the GI tract (oral); 0.3-4.5% from intact scalp (topical).
Distribution: Enters breast milk.
Metabolism: Extensively hepatic via glucuronidation.
Excretion: Via urine as metabolites. Elimination half-life: Approx 4.2 hr.
Chemical Structure

Chemical Structure Image
Minoxidil

Source: National Center for Biotechnology Information. PubChem Database. Minoxidil, CID=4201, https://pubchem.ncbi.nlm.nih.gov/compound/Minoxidil (accessed on Jan. 22, 2020)

Storage
Store below 25°C.
MIMS Class
Other Dermatologicals
References
Anon. Minoxidil (Systemic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 13/10/2015.

Anon. Minoxidil (Topical). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 13/10/2015.

Buckingham R (ed). Minoxidil. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 13/10/2015.

Womens Rogaine Unscented Aerosol, Foam (Johnson & Johnson Consumer Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 13/10/2015.

Disclaimer: This information is independently developed by MIMS based on Minoxidil from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by MIMS.com
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