Topical finasteride in the treatment of androgenic alopecia. Preliminary evaluations after a 16-month therapy course

The enzyme 5α-reductase (5AR), which catalyzes reduction of testosterone to the more potent metabolite dihydrotestosterone, has been assumed to play a key role in a variety of skin disorders, including acne, seborrhea, hirsutism, and androgenic alopecia (AA). Also, evidences have been provided supporting the pathogenetic relevance of higher rates of testosterone reduction at lesional level. The azasteroid finasteride, a 5AR inhibitor, is widely employed in the treatment of benign prostatic hyperplasia; by contrast, its potential role in other androgen-related conditions have been, so far, only poorly evaluated. We present herein the results of a single-blind, placebo-controlled, 16-month trial carried out in 52 patients with AA using a 0.005% finasteride solution. The clinical outcome, in terms of both hair regrowth and balding areas reduction, seems to be encouraging, in the absence of either any evidence of percutaneous absorption of finasteride, or local/systemic untoward effects. We also briefly review the possible pharmacodynamic and pharmacokinetic bases of the use of topically delivered finasteride in AA.