April 29, 2011;  Updated September 10, 2012

Since 1998, finasteride (Propecia®) has successfully helped millions of men with androgenetic alopecia with a relatively low side effect profile. Recently, several reports in the media and health-related literature have described a number of younger men with androgenetic alopecia who claim to have experienced persistent sexual side effects following the use and subsequent discontinuation of finasteride. The International Society of Hair Restoration Surgery (ISHRS) has established the Task Force on Finasteride Adverse Event Controversies to evaluate published data and to inform and update our ISHRS members regarding the use of this medication.

To date, there is no evidence-based data substantiating the link between finasteride and persistent sexual side effects in the numerous double blinded, placebo controlled studies using finasteride 1mg for hair loss. Reports of persistent sexual side effects have come from a variety of sources, with some internet sites attracting individuals claiming to have sexual and psychological issues related to finasteride. While continued difficulty having erections after discontinuing finasteride has been reported in post-marketing surveillance the incidence of this problem remains unknown. This rare side effect is included in Merck’s patient product information in the United States, and in Public Assessment Reports of the Medicines and Health Regulatory Agency of the United Kingdom and the Medical Products Agency of Sweden.

On April 11, 2012, the U.S. Food and Drug Administration (FDA) announced changes to the professional labels for Propecia (finasteride 1 mg) and Proscar (finasteride 5 mg) to expand the list of sexual adverse events reported to FDA as some of these events have been reported to continue after the drug is no longer being used (note that erectile dysfunction after stopping use of these drugs was added as a known event in 2011). The new label changes include:

  • A revision to the Propecia label to include libido disorders, ejaculation disorders, and orgasm disorders that continued after discontinuation of the drug.
  • A revision to the Proscar label to include decreased libido that continued after discontinuation of the drug.
  • A revision to both the Propecia and Proscar labels to include a description of reports of male infertility and/or poor semen quality that normalized or improved after drug discontinuation.

Despite the fact that clear causal links between finasteride (Propecia and Proscar) and sexual adverse events have NOT been established, the cases suggest a broader range of adverse effects than previously reported in patients taking these drugs.  Information about these adverse events may be important to individual patients.  Therefore, prescribers and patients need to be aware of them, as part of a discussion of risk and benefits of finasteride when determining the best treatment options.  (Excerpt from FDA site: http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm299754.htm)

The persistence of sexual side effects appears to be a rare event, and it has yet to be determined whether these recent reports represent a true causal relationship, or if they are simply coincidental and related to other factors such as the high incidence of sexual dysfunction in the general population, and/or the placebo effect. Also, little data is available concerning the medical and psychological workup of these patients to exclude other potential causative factors.

At the present time, the mechanism of interaction between the brain, 5 alpha-reductase metabolism, and hormones on sexual dysfunction is speculative and poorly understood. Clearly, this is a complicated issue, which overlaps with other disciplines in medicine such as Endocrinology, Urology, and Psychiatry. More research is needed to assess the actual incidence of side effects, to determine if there is a true causal relationship for persistent side effects, and, if so, to identify who may be at risk. We hope to participate in a multidisciplinary forum to further evaluate this topic.

Millions of patients have benefitted from finasteride with no side effects at all, or minimal and reversible side effects. It is important for the medical community to verify anecdotal reports, and, if necessary, conduct further studies so that accurate information may be given to our patients to enable them to make informed choices regarding the use of this medication.

The ISHRS Task Force on Finasteride Adverse Event Controversies is in the process of gathering information and forming an interdisciplinary panel to address these issues and to keep our ISHRS members informed regarding post- marketing adverse events.

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