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What Is Minoxidil ?/Minoxidil is an orally administered vasodilator with hair growth stimulatory and antihypertensive effects. Minoxidil is converted into its active metabolite minoxidil sulfate by sulphotransferase enzymes. Minoxidil sulfate exerts its antihypertensive effect by the opening of plasma membrane adenosine triphosphate (ATP)-sensitive potassium channels (KATP channels), thereby directly and rapidly relaxing the arteriolar smooth muscle and subsequent reduction of elevated systolic and diastolic blood pressure by decreasing peripheral vascular resistance. This agent’s hair growth stimulatory effect may be mediated through its vasodilatory activity, thereby increasing cutaneous blood flow, or due to its direct stimulatory effect on hair follicle cells and forcing them from their resting phase into their active growth phase.
Minoxidil is an antihypertensive agent that is used largely for patients with severe and refractory hypertension not responding to conventional therapies. Minoxidil is also used topically to treat male pattern baldness. Despite its use for many years, minoxidil has not been convincingly linked to cases of clinically apparent liver injury.
Mechanism of Action of Minoxidil
Minoxidil is thought to promote the survival of human dermal papillary cells (DPCs) or hair cells by activating both extracellular signal-regulated kinase (ERK) and Akt and by preventing cell death by increasing the ratio of BCl–2/Bax. Minoxidil may stimulate the growth of human hair by prolonging anagen through these proliferative and anti-apoptotic effects on DPCs. Minoxidil, when used as a vasodilator, acts by opening adenosine triphosphate-sensitive potassium channels in vascular smooth muscle cells. This vasodilation may also improve the viability of hair cells or hair follicles.
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The mechanism(s) by which topically applied minoxidil and/or a metabolite of the drug stimulates vertex hair regrowth in androgenetic (male-pattern) alopecia or other forms of alopecia has not been fully elucidated. However, because minoxidil has stimulated hair regrowth in several forms of alopecia, it appears that the drug acts at the level of the hair follicle, possibly involving direct stimulation of hair follicle epithelial growth. … While increased scalp blood flow resulting from local vasodilation often has been proposed as a principal mechanism of minoxidil’s effect on hair growth, this mechanism has not been substantiated consistently and not all vasodilators produce hypertrichosis.
Indications of Minoxidil
- For the treatment of severe hypertension and in the topical treatment (regrowth) of androgenic alopecia in males and females and stabilisation of hair loss in patients with androgenic alopecia.
- Minoxidil is an antihypertensive agent that is used largely for patients with severe and refractory hypertension not responding to conventional therapies. Minoxidil is also used topically to treat male pattern baldness.
- Minoxidil is used topically to stimulate regrowth of hair in balding areas of individuals with androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness).
- Androgenetic Alopecia
- Severe, symptomatic Hypertension
Contraindications of Minoxidil
- pheochromocytoma
- heart attack within the last 30 days
- angina
- a type of chest pain
- infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation of the covering of the heart or pericardium
- pericardial tamponade
- a disorder of the heart
- fluid in the covering of the heart or pericardium
- chronic heart failure
- a disorder of the blood vessels of the brain
- kidney disease with a reduction in kidney function
- are allergic to minoxidil or any ingredients of the solution
- are bald due to non-hereditary factors (e.g., caused by illnesses such as iron deficiency, thyroid disorders, or medications such as cancer chemotherapy)
- have hair loss associated with childbirth
- have a skin condition on the scalp (e.g., psoriasis or sunburns)
- are or may be pregnant or are nursing
- are using other skin medications or dressings on the scalp (e.g., for psoriasis)
- have shaved, broken, inflamed, irritated, infected, or severely sunburned skin on the scalp
- have untreated high blood pressure
- have recently discontinued certain medications such as birth control or cancer chemotherapy
- have certain grooming habits (e.g., cornrowing, tight ponytails)
Dosage of Minoxidil
Strengths: Tablets, 2.5, 5 mg and 10 mg (Loniten). The topical solution, 2% (Rogaine)
Hypertension
- Initial dose: 5 mg orally once a day
- Maintenance dose: 10 to 40 mg per day
- Maximum dose: 100 mg per day
Alopecia
Solution
- Apply 1 mL topically to the affected area(s) of the scalp twice a day. The dose should not exceed 2 mL per day.
Pediatric Dose for Hypertension
Less than 12 years
- Initial dose: 0.2 mg/kg orally once a day
- Maintenance 0.25 to 1 mg/kg/day
- Maximum dose: 50 mg per day
Over 12 years
- Initial dose: 5 mg orally once a day
- Maintenance dose: 10 to 40 mg per day
- Maximum dose: 100 mg per day
Side Effects of Minoxidil
More common
- Fast or irregular heartbeat
- weight gain (rapid) of more than 5 pounds (2 pounds in children)
- backache
- changes in hair colour or texture
- cold- or flu-like symptoms (e.g., runny or stuffy nose, cough, sore throat)
- continuous itching or skin rash
- dental problems
- eye irritation
- irritation, redness, dryness in the area where medication was applied
- muscle strain or spasm
Common
- Chest pain
- shortness of breath
- acne where medication was applied
- burning of the scalp
- changes in blood pressure
- dizziness
- feeling faint
- pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache
- infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation or soreness at the hair root
- persistent local rash
- rapid heartbeat
Rare
- Bloating
- flushing or redness of skin
- swelling of feet or lower legs
- Numbness or tingling of hands, feet, or face
- Skin rash and itching
- rapid weight gain
- sudden weight gain
- swelling of the hands or feet
- temporary hair loss
- unwanted facial hair growth
Drug Interactions of Minoxidil
Minoxidil may interact with following drugs, supplements, & may change the efficacy of drugs
- amifostine
- anthralin
- blood-pressure-lowering medications
- other topical (applied to the skin) medications
- rituximab
- topical corticosteroids (e.g., betamethasone, hydrocortisone)
- tretinoin
- amphetamine / dextroamphetamine
- aspirin
- diphenhydramine
- tadalafil
- CoQ10
- finasteride
- Fish Oil (omega-3 polyunsaturated fatty acids)
- fluticasone nasal)
- atorvastatin
- Omega-3 (omega-3 polyunsaturated fatty acids)
- Probiotic Formula (bifidobacterium infantis / lactobacillus acidophilus)
- finasteride
- levothyroxine
- sildenafil
- Vitamin B12 (cyanocobalamin)
- Vitamin C (ascorbic acid)
- Vitamin D2 (ergocalciferol)
- Vitamin D3 (cholecalciferol)
- alprazolam
- cetirizine
Pregnancy Category of Minoxidil
Pregnancy
This medication should not be used during pregnancy. If you become pregnant while taking this medication, stop taking it and contact your doctor immediately.
Breast-feeding
This medication passes into breast milk. If you are a breast-feeding mother and are using minoxidil, it may affect your baby. Women who are breast-feeding should not use minoxidil. The safety and effectiveness of using this medication have not been established for children under 18 years of age.
References
