Minoxidil

Many systemic medications prescribed for various reasons can cause general hypertrichosis as a side effect, and also have a positive effect on the condition of the hair on the scalp (benoxaprofen, cyclosporine A, PUVA), but their targeted systemic use for common baldness is unjustified due to undesirable complications.

Of the systemic trichogenic agents, only minoxidil produces significant clinical improvement when applied topically. Minoxidil (Loniten), a piperidinopyridamine derivative, is a potent vasodilator when administered systemically and is indicated for severe hypertension. When applied topically as a 2% solution, minoxidil (Rogaine, Regaine, Alopecia, etc.) converts vellus hair to terminal hair in 30% of patients. The drug restores terminal hair growth at the edges of the bald patch and sometimes (<10% of patients) over the entire surface.

In men, minoxidil is more effective in the early stages of baldness (< 10 years) with a bald spot diameter of no more than 10 cm and a hair density of at least 20/cm ². The solution is applied to thoroughly dried scalp twice a day, morning and evening, 1 ml. It is colorless, odorless, and quickly absorbed. After applying the preparation, you can use any hair styling products.

Local treatment with minoxidil can be compared to the treatment of diabetes with insulin: continuous use of the drug is necessary, since 3 months after stopping treatment, baldness resumes.

In young subjects who are starting to go bald, the cosmetic effect is better and achieved more quickly than in older people with large bald spots.

The effectiveness of treatment in women is slightly higher than in men. The peak of effectiveness is observed after a year from the start of therapy, then the rate of transformation of vellus hair into terminal hair decreases. The question of the necessary topical application of minoxidil in hair transplantation has not been resolved. The drug is not effective in baldness caused by chemotherapy.

Side effects. Allergic dermatitis develops rarely (< 19 patients). Folliculitis may occur in 3-5% of patients. There have been rare reports of increased hair growth outside the area of application of the drug (eyebrows, beard, hands, ears). There is no effect on hemodynamics in hypertensive patients and people with normal blood pressure.

In isolated cases, changes in blood pressure, palpitations, chest pain, shortness of breath, arrhythmia, headache, and dizziness are possible.

Contraindication is hypersensitivity to minoxidil.

The mechanism by which minoxidil or its metabolite, minoxidil sulfate, stimulate hair growth remains unclear. The drug may act at the hair follicle level by regulating potassium channels. Direct stimulation of the follicle epithelium may also occur. In an experiment with animal hair follicle cultures, minoxidil increased cysteine uptake, proliferation of matrix and outer root sheath cells, and promoted normalization of follicle morphology. Recent studies have shown that minoxidil promotes dermal papilla vascularization by inducing angiogenesis. The role of increased scalp blood flow remains to be elucidated. It can be argued that minoxidil is not an antiandrogen, since no changes in serum and urinary androgen concentrations were observed in patients.

Thus, when using the drug, the miniaturization of the hair follicle stops, its cycle is normalized; which leads to an increase in the diameter of the hair produced and an increase in the length of the follicle. As the results of the histological study showed, the above changes in patients become clearly expressed after 5 weeks of therapy.

Recently, a new, more concentrated solution of minoxidil (5%) has been developed, which allows for a higher concentration of the drug at the hair follicle level. The solution is applied in the usual twice-daily regimen; the desired result is achieved in a shorter period of time.

Minoxidil analogues

Aminexil (Aminexil, Dercap) is a structural analogue of minoxidil. According to a clinical study, aminexil reduces hair loss in 8% of men and 66% of women. Hair diameter increased in 80% of women. The drug is included in the shampoo for washing hair (L'Oreal).

Cromakalim (BRL 34915) acts like minoxidil on potassium channels and stimulates DNA synthesis in keratinocytes and hair follicles. The drug was also initially used to treat hypertension. The use of Cromakalim for hair regrowth is patented by Upjohn Company.

Diazoxide (Hyperstat IV, Proglycem) is an antihypertensive agent that acts through potassium channels; like minoxidil, it causes hair growth. Since diazoxide exists only as a blood pressure lowering agent, it is recommended to prepare the preparation for topical treatment of alopecia at home.

Pinacidil is an antihypertensive agent that causes hair growth similar to minoxidil. It is undergoing clinical testing as an anti-baldness agent.

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