Minoxidil, is the first FDA approved medication for the treatment of hair loss. Topical minoxidil is available without a prescription as 2% solution, 5% solution, and 5% foam. is a topical minoxidil solution is applied directly to the scalp in concentrations of 5% (for men) and 2% (for women).
Minoxidil promotes hair growth by increasing the duration of anagen, shortening telogen, and enlarging miniaturized follicles. The pathophysiologic mechanism through which minoxidil influences follicular structure and follicular cycling is unclear,
Patients utilizing minoxidil for androgenetic alopecia should be advised of the following:
- Minoxidil solution is to be used for an indefinite time. Once stopped, any hair regrowth eventually will be lost, often over the course of several months.
- Minoxidil is a scalp treatment, not a hair treatment, and must be used exactly as prescribed for maximum benefit.
- Men should apply 1 mL of minoxidil 5% solution(2% for women) or one half of a capful of the 5% foam twice daily to involved areas on a dry scalp. The solution can be spread lightly with a finger; massage is not needed.
- Hair shedding may occur at the initiation of treatment and is thought to occur as a result of the stimulation of telogen follicles to reenter the anagen phase . The increased hair loss usually resolves within two months. Patients should be warned of this side effect to prevent the premature discontinuation of treatment.
- Minoxidil must be used twice a day for at least four months prior to evaluating the initial response to therapy . Hair shedding may occur at the initiation of treatment and usually decreases within two months. Hair growth may be seen within four to eight months and stabilizes at 12 to 18 months. Thus, a full year of treatment is recommended before assessing treatment efficacy.
The main side effect of topical minoxidil is hypertrichosis, mostly from local spreading or excessive continuous topical application. The other side effects are contact dermatitis and irritant dermatitis. When given systemically, minoxidil has antihypertensive properties, but neither 5% nor 2% minoxidil solution alters systolic or diastolic blood pressure, pulse rate, or body weight when applied topically . Nevertheless, due to the potential for systemic absorption when the scalp skin barrier is not intact, caution should be used in patients with cardiovascular disease.