Dutasteride (Avodart) is marketed exclusively for benign prostatic hyperplasia, i.e., to reduce an enlarged prostate to improve urinary flow. However, that does not mean that it is unsafe or not recommended for hair loss since the company (GlaxoSmithKline) that manufacturers it has never sought the indication for hair loss from the Food & Drug Administration (FDA), which can be an expensive endeavor.

Like finasteride (Propecia), dutasteride is a dihydrotestosterone (DHT) blocker, i.e., it blocks the conversion of testosterone to DHT, which in turn limits hair loss since the presence of DHT impacts male pattern baldness. However, unlike finasteride, dutasteride not only blocks DHT2 but also DHT1 so it is a more universal blockade of DHT. Some initial studies have shown great efficacy with dutasteride than with finasteride. Although dutasteride can be potentially more efficacious than finasteride, the question is at what cost, especially to the younger male. It is unclear whether side effects are worse but some studies report more severe sexual side effects than with finasteride and there is the potential for dutasteride to cross the blood-brain barrier unlike finasteride. For all of these reasons, I do not routinely prescribe dutasteride and only do so in the younger male patient who is willing to accept the risks because he is desperate for a solution and has not been successful with a course of finasteride. In general, I rarely prescribe the medication not because I believe it is unsafe but because I do not believe we have sufficient data at this time to know the long-term consequences of dutasteride.

Samuel M. Lam, MD, FACS, a board certified hair transplant surgeon in Dallas, Texas. To learn more about hair loss, or to schedule a consultation please call 972-312-8105, or visit hairtx.com for more info. To ask Dr Lam a question please visit our hair loss forum.