5 alpha reductase inhibitor induced gynecomastia
5 alpha reductase inhibitors like finasteride and dutasteride are widely used to treat androgenetic alopecia. Gynecomastia or breast enlargement is a side effect that one needs to be aware of. It occurs in 4 to 10 out of every 1,000 users.
Key points about gynecomastia from 5 aha reductase inhibitors
Gynecomastia from these drugs is often one-sided but can be both sides. Changes can start as early as a few weeks but is typically a few months delay (if it is going to occur). It can also be 1-2 years before the phenomenon is appreciated. An important sign to watch for is the presence of pain or tenderness. This can occur in many males prior to any actual enlargement. Lower doses are less likely to cause breast enlargement in men compared to higher doses. The concept of the dose response is important because it means than for some men, 0.5 mg daily (or every other day) could be assocated with a lower risk of gynecomastia (while still potentially benefitting their hair). Finasteride induced gynecomastia can reverse in many individuals provided the drug is stopped in the early stages when the gynecomastia is noted. If the drug is not stopped, it can enter a irreversible stage (where only surgery will provide treatment). Finasteride induced gynecomastia is more likely with advanced age and in obese individuals. Blood tests may be appropriate for some men depending on their history. However, most of the time blood tests and various hormonal tests are normal.
Treatment of Gynecomastia from 5 alpha reductase inhibitors
I'm often asked how gynecomastia should be treated. This simplest and more consistently helpful answer is to immediately stop the drug as soon as gynecomastia is noticed. Most men (but not all) will notice resolution of the gynecomastia with stopping the drug. Of course, the benefits for the hair will be lost.
One should discuss the issue in detail with their physician. One need to make sure that the gynecomastia is indeed occurring due to the use of the 5 alpha reductase inhibitor and not another cause. For some males, a reduction in the overall dose of the drug may reduce the gynecomastia yet still benefit the hair. For many males with gynecomastia, especially if it has been present for a longer period of time, surgery is needed to remove the excess tissue.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299