Topical 5-a reductase inhibitors in the treatment of androgenetic alopecia and acne vulgaris
Oral finasteride is effective in the treatment of androgenetic alopecia (AGA) by inhibiting 5-a reductase enzyme activity, which converts testoster- one to dihydrotestosterone. A single-blinded, placebo-controlled trial was carried out in 52 pa- tients with AGA, and revealed that a 0.005% finasteride solution had a promising effect on hair growth and balding area reduction after 16 months.69 The result of a recent RDBPCT showed no significant statistical differences in the number of terminal hairs, total hair count, and size of alopecia area between oral finasteride and 1% finasteride gel- treated groups after 6 months.70 Dutasteride, an- other 5-a reductase enzyme inhibitor and indicated for benign prostate hyperplasia, has also been used topically for the treatment of AGA. However, there are no published clinical studies to prove its efficacy.
Androgen controls sebum production and also plays a vital role in acne. In a preliminary study, Kohler et al71 reported that 9 of 12 women with acne and alopecia benefited from oral finasteride. Suppression of dihydrotestosterone in serum and sebum by a 5-a reductase inhibitor was also dem- onstrated in a RDBPCT, which suggests the potential use of 5-a reductase inhibitor in the treatment of acne.72 However, in a recent RDBPCT, systemic administration of a type I 5-a reductase inhibitor failed to show clinical improvement of acne when used alone.73 In an animal study by Ye et al,74 topical finasteride induced a moderate degree of lobular and ductal regression of sebaceous glands in male fuzzy rats. No serum level changes of testosterone or dihydrotestosterone were detected. Topical finaster- ide has not been tested in human studies for the treatment of acne. Local or systemic tolerance of topical finasteride was very good and only transient erythema was reported.
Topical use of systemic drugs in dermatology: A comprehensive review. Hsien-Yi Chiu, MD, and Tsen-Fang Tsai, MD. Taipei, Taiwan
mi aspetterei una replica da parte dei dermatologi che frequentano questo forum ;-)