Why can’t finasteride be used to treat androgenetic alopecia in women who have high levels of 5α-reductase?
—Fred A. Stutman, MD, Philadelphia
Oral finasteride, a type II 5α-reductase inhibitor, has been shown to increase hair growth and slow progression of thinning in men with androgenetic alopecia (AGA) or male-pattern balding, but this agent has no affect on hair growth in postmenopausal women with female-pattern hair loss. One study showed that in postmenopausal women with AGA, finasteride 1 mg/day taken for 12 months did not increase hair growth or slow the progression of hair thinning (J Am Acad Dermatol. 2000;43[5 Pt 1]:768-776). In another study, Price and colleagues reported that finasteride improved or stabilized hair loss with characteristics of both male and female patterns in four women with hyperandrogenism. Because there was improvement of pattern hair loss in women with hyperandrogenism but no improvement in postmenopausal women who had female-pattern hair loss without hyperandrogenism, the findings support the concept that not all types of female alopecia have the same pathophysiology (J Am Acad Dermatol. 2002;47:733-739).
—Jeffrey M. Weinberg, MD (114-4)