5α-Reductase inhibitors in androgenetic alopecia.

PURPOSE OF REVIEW: The authors will review the current literature on efficacy and safety of 5-alpha reductase inhibitors (5αRIs) for androgenetic alopecia (AGA). RECENT FINDINGS: The 5αRI finasteride and dutasteride are effective in treating AGA and promoting hair regrowth. 5αRI can be given orally, topically and more recently through mesotherapy. However, there has been an increasing concern about permanent sexual adverse events such as impotence and infertility. Most of these reports are published as case reports, and two studies reporting persistent sexual side-effects after discontinuation of finasteride had serious method limitations, as patients were recruited from a website. To our knowledge, permanent sexual adverse events have yet to be published in higher quality studies, such as randomized controlled trials. Although patients treated with 5αRIs have an increased incidence of sexual adverse events, these events decrease if discontinued or over time with continued therapy. SUMMARY: Sexual side-effects are uncommon and resolve spontaneously in most patients even without discontinuing therapy. Significant effort is underway to find delivery systems that optimize delivery and reduce systemic absorption of topical 5αRs including hydroxypropyl chitosan and liposomal and nanoparticulate systems.