Brand names: Hair Regrowth, Rogaine, Theroxidil
Drug class: Skin and Mucous Membrane Agents, Miscellaneous
- Hair Growth Stimulants
ATC class: C02DC01
VA class: DE900
Chemical name: 3-oxide 6-(1-piperidinyl)-2,4-pyrimidinediamine
Molecular formula: C₉H₁₅N₅O
CAS number: 38304-91-5

Medically reviewed by Drugs.com on Oct 24, 2022. Written by ASHP.

Introduction

Hair stimulant; a piperidinopyrimidine-derivative vasodilator.

Uses for Minoxidil (Topical)

Androgenetic Alopecia

Stimulates regrowth of hair in men and women with androgenetic alopecia (male-pattern alopecia, hereditary alopecia, common male baldness).

Recommended for use in men who have general thinning of hair at the vertex of the scalp and in women who have general thinning of hair in frontoparietal areas. May be ineffective in men or women with more extensive hair loss.

Not recommended for patients without a family history of hair loss or for those with hair loss associated with childbirth, or for those who have hair loss that occurs suddenly or for unknown reasons.

Generally most effective in men <40 years of age, with <10 years duration of hair loss, <10 cm diameter of baldness, and with large number of terminal or intermediate hairs before initiation of therapy.

Alopecia Areata

Has been used to promote hair regrowth in males and females with alopecia areata^{† [off-label]}, including alopecia totalis or universalis.

Hair Transplantation

Has been used as an adjunct to hair transplantation^{† [off-label]}; may promote better evolution of hair grafts by reducing postoperative shedding of hair and hastening the onset of postsheddng hair regrowth.

Minoxidil (Topical) Dosage and Administration

Administration

Topical Administration

Apply topically to the scalp as a 2 or 5% solution or as a 5% foam.

For dermatologic use only; avoid contact with eyes, mucous membranes, or sensitive or abraded skin areas. (See Dermatologic Effects under Cautions.) If contact with any of these areas occurs, flush area with large amounts of cool water.

Apply to the scalp only; do not apply to other areas of the body because of risk of systemic adverse effects. (See Systemic Effects under Cautions.)

In men, apply 2 or 5% solution or 5% foam to total affected (balding and anticipated balding) areas of the scalp twice daily, usually in the morning and evening.

In women, apply 2% solution to total affected areas of the scalp twice daily, usually in the morning and evening; 5% solution and 5% foam should not be used in women.

Apply solution and foam to dry scalp.

To apply solution, use applicator provided by the manufacturer and apply evenly over total affected areas of the scalp.

To apply foam, part hair into ≥1 rows to expose scalp. Rinse hands with cold water and dry thoroughly to minimize foam melting on warm skin. Hold container upside down and press nozzle to dispense ½ capful of foam onto fingers; apply foam to affected areas and gently massage into scalp.

Wash hands thoroughly after application using fingertips.

Dosage

Adults

Androgenetic Alopecia

Treatment in Men

Topical

Apply 1 mL of 2 or 5% solution to affected areas of the scalp twice daily.

Apply ½ capful of 5% foam to affected areas of the scalp twice daily.

≥4 months of use may be necessary before regrowth observed. Therapy must be continued indefinitely for maintenance of hair growth.

Treatment in Women

Topical

Apply 1 mL of 2% solution to affected areas of the scalp twice daily.

≥4 months of use may be necessary before regrowth observed. Therapy must be continued indefinitely for maintenance of hair growth.

Alopecia Areata† [off-label]

Topical

Apply 1 mL of 5% solution to affected areas of the scalp twice daily.

Prescribing Limits

Adults

Androgenetic Alopecia

Treatment in Men

Topical

Maximum 2 mL of 2 or 5% solution daily.

Maximum ½ capful of 5% foam per application.

Treatment in Women

Topical

Maximum 2 mL of 2% solution daily.

Special Populations

No special population dosage recommendations at this time.

Cautions for Minoxidil (Topical)

Contraindications

• Known hypersensitivity to minoxidil or any ingredient in the formulation.

Warnings/Precautions

General Precautions

Dermatologic Effects

Possible adverse local dermatologic effects (e.g., pruritus, dryness, scaling/flaking, local irritation or burning); may occur more frequently with the 5 than the 2% topical solution and may result from alcohol contained in formulation and the wearing of a wig or hairpiece. Local irritation usually is mild and rarely requires discontinuance of therapy.

If irritation occurs, flush area with large amounts of cool water; contact clinician if irritation persists.

Increased hair growth outside area of drug application (e.g., face, beard, eyebrows, ear, arm) reported; possibly due to inadvertent transfer of drug solution.

Systemic Effects

Potential systemic adverse effects (e.g., weight gain, edema, tachycardia, hypotension), especially in individuals with propensity for greater percutaneous absorption or with increased sensitivity to the drug. Excessive doses, local abrasion or inflammation, or severe sunburn also may increase risk of systemic effects.

Use not recommended on inflamed, erythematous, infected, irritated, or painful scalp.

Exposure to UV Light

Severe UV light-induced skin injury (e.g., severe sunburn) may enhance percutaneous absorption and increase risk of systemic effects. (See Systemic Effects under Cautions.)

Specific Populations

Pregnancy

Category C.

Lactation

Distributed into milk after oral administration; however, not known whether topical minoxidil is distributed into milk. AAP classifies minoxidil as compatible with breast-feeding.

Pediatric Use

Safety and efficacy not established in children <18 years of age.

Women

Prior to initiating therapy for androgenetic alopecia, consider possibility of an underlying endocrine abnormality (e.g., polycystic ovary [Stein-Leventhal] syndrome, Cushing’s syndrome, androgen-secreting tumors, hypothyroidism).

Severe, diffuse hypertrichosis involving the face and limbs reported in women after 2–3 months of therapy with 5% solution for treatment of androgenetic alopecia; resolved within 4–5 months following discontinuance of therapy.

Common Adverse Effects

Pruritus, dryness, scaling/flaking, local irritation or burning.

Interactions for Minoxidil (Topical)

Topical Preparations

Possible pharmacokinetic interaction (increased percutaneous absorption of minoxidil). Safety and efficacy of combined therapy with other topical drugs not established. Concomitant use with other topical drugs on the scalp is not recommended.

Specific Drugs

Minoxidil (Topical) Pharmacokinetics

Absorption

Bioavailability

Minimally absorbed following topical application to intact scalp; 1.4% of a 2% topical solution may be absorbed.

Onset

Onset of hair regrowth is variable; however, 2 or ≥4 months usually required before evidence of regrowth is observed following topical administration with 2 or 5% topical solutions, respectively.

Distribution

Extent

Not fully determined following topical administration; however, intact stratum corneum may serve as a barrier that inhibits substantial diffusion of topically applied minoxidil into systemic circulation.

Not known whether topical minoxidil crosses the placenta or is distributed into milk.

Elimination

Metabolism

Not fully determined following topical administration; however, appears to be converted in the hair follicle to an active metabolite, minoxidil sulfate, by minoxidil sulfotransferase.

Elimination Route

Excreted principally in urine.

Stability

Storage

Topical

Solution

20–25°C. Keep away from heat and flame.

Foam

20–25°C. Keep away from heat and flame; do not puncture or incinerate container.

Actions

• Exact mechanism of action not fully elucidated; however, appears to act at the level of the hair follicle, possibly directly stimulating hair follicle epithelial growth.

• May induce follicle hypertrophy and a return to more normal hair follicle diameter and depth in existing small follicles (i.e., regrowth) rather than stimulation of new follicle formation.

• Appears to prolong the anagen phase of the hair follicle, and accelerate the cyclic turnover of vellus hair follicles, enabling these follicles to produce thick, terminal hair

• May directly induce proliferation of hair epithelial cells near the base of the hair follicle and increase incorporation of cysteine and glycine into the follicle; cysteine residues cross-link to form cystine, which provides strength to the hair shaft.

Advice to Patients

• Product is flammable; importance of keeping product and area of application away from open flame and heat.

• Importance of using only as directed, only for the indicated types of hair loss, and for at least 2–4 months in order to see results; continuous use required to maintain hair regrowth. (See Topical Administration under Dosage and Administration.)

• Importance of applying only to healthy, normal scalp and not using topical minoxidil if scalp is inflamed, erythematous, infected, irritated, or painful. Importance of avoiding contact with the eyes.

• Importance of washing hands after application.

• Importance of women using only 2% solution; 5% solution and 5% foam should not be used in women.

• Importance of reporting any local or systemic adverse reactions, especially chest pain, tachycardia, dizziness, unexplained weight gain, or peripheral edema, to a clinician.

• Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as concomitant illnesses.

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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