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Propecia and Erectile Dysfunction

man with hands over eyesMerck’s popular male pattern baldness drug Propecia (finasteride) first received approval from the U.S. Food and Drug Administration in 1997, following a series of clinical trials showing its ability to successfully stimulate hair growth and facilitate retention of existing hair. In the span of a few short years, Propecia became a true market leader, with millions of prescriptions written annually. Though the drug’s label made mention of a small risk of sexual side effects, including impotence, a large number of men seeking a solution to baldness made eager use of the medication.

In subsequent years, however, reports of sexual dysfunction stemming from Propecia use emerged, including allegations of ongoing, perhaps permanent harm developing even after use of the medication ceased. As a result, Merck undertook several post-market studies which ultimately prompted changes to Propecia’s warning labels, alerting patients to a more significant risk of lasting, negative effects.

Propecia and sexual side effects

Propecia functions by blocking a particular enzyme within the body known to change testosterone to dihydrotestosterone. While this mechanism works to stave off hair loss in a large number of male patients, it has also caused some to experience impotence along with depression, memory loss and other cognitive difficulties.

One of the most troubling sexual side effects linked to Propecia is that of erectile dysfunction, often referred to as ED. Those suffering from ED have ongoing trouble achieving or sustaining an erection and may experience a drastic drop in libido. Use of finasteride is just one possible cause of ED, with emotional and psychological factors playing a role in many cases.

Other possible triggers of ED include:

  • Use of SSRI medications for depression
  • Neurological problems
  • Smoking
  • Cardiovascular conditions
  • Stress
  • Hormonal imbalances
  • Obesity
  • Kidney ailments
  • Use of non-steroidal anti-inflammatory drugs

Determining the true cause of ED

Individuals suffering from ED who also believe that Propecia may be to blame ought to undergo further assessment in order to determine the true cause of their condition. Simultaneous use of the baldness drug and episodes of ED are not necessarily related, and it is important to isolate other potential reasons for the disorder. Physicians have a number of testing procedures at their disposal which can prove helpful in pinpointing the underlying source of trouble.

Tests to assess the causes of erectile dysfunction include:

  • Use of Rigiscan monitoring device
  • Snap gauge test
  • Doppler measurement of penile brachial index
  • Magnetic resonance angiography
  • Bulbocavernosus reflex test

These tests can prove extremely valuable in determining whether or not a particular patient’s ED is likely the result of psychological, emotional or physiological issues. This process can therefore help evaluate the possibility that Propecia played a role in reduced sexual function in a given individual.

Research studies lead to broader concern about Propecia

Numerous research studies have explored the possible connection between Propecia and sexual dysfunction. In 2003, Merck funded a study in which it was revealed that the sexual side effects of the drug may linger even after use of the drug is suspended. The drug maker emphasized its belief that such effects ultimately resolve on their own in most patients and that the ED of many patients was the result of unrelated factors.

However, a subsequent study performed by researchers at George Washington University found that the sexual side effects experienced by Propecia users were long-term in nature and did not generally resolve themselves after use of the medication ceased.

In 2012, the FDA released results of its own study of finasteride sexual side effects, identifying persistent dysfunction of a lasting nature in roughly 14 percent of subject cases. Though hesitant to declare the existence of a direct causal connection, the agency called for updating of product labels to reflect the potential risk.

European regulatory agencies began exploring reports of severe sexual side effects linked with Propecia since 2006, including allegations that complications such as erectile dysfunction continued even after patients halted their use of the drug. As a result, Merck altered the labeling used in Italy, Sweden and the United Kingdom, informing patients of the possibility of serious, lingering sexual problems following finasteride use.

Though the drug maker has made adjustments to labeling in the United States in response to FDA mandates, the product still does not bear a comprehensive statement concerning the likelihood of debilitating, long-lasting sexual dysfunction.

Alleged inadequacy of Propecia ED warnings

The controversy regarding the use of Propecia and the subsequent development of erectile dysfunction and other sexual side effects shows no sign of abating. This fact is evidenced by a 2015 study authored by researchers from the Northwestern University School of Medicine and published in the Journal of the American Medical Association. Researchers came to the conclusion that prior clinical trials involving finasteride provided insufficient reporting on possible sexual side effects, and that patients need to be informed of the very real risk of potentially permanent harm, including erectile dysfunction.

Further, a senior scientist from the Institute for Safe Medication Practices recently stated in an interview with JAMA Dermatology that it is now quite clear that finasteride does negatively impact sexual function in males, and expressed frustration that the fact did not present itself more plainly in the years of clinical trials that preceded the drug’s explosion in popularity.

Propecia erectile dysfunction lawsuits

Hundreds of Propecia lawsuits involving allegations of serious sexual side effects have been consolidated into multidistrict litigation (MDL) as a way to streamline pretrial procedures, conserve judicial resources and facilitate global settlement opportunities. As more and more male patients discover that the sexual dysfunction they have experienced after using Propecia is not abating, it is likely that the plaintiff pool will continue to expand. Whether a large-scale settlement of finasteride litigation is achievable remains to be seen.


  1. ABC News, Baldness Drug's Sex Effects Possibly Permanent, Study Says, http://www.abcnews.go.com/Health/baldness-drug-propecia-long-lasting-possibly-permanent-sexual/story?id=16758123

  2. Mayo Clinic, Finasteride (Oral Route), http://www.mayoclinic.org/drugs-supplements/finasteride/oral-route/side-effects/drg-20063819

  3. CBS News, FDA adds sexual side effects warning to baldness drug Propecia, http://www.cbsnews.com/news/fda-adds-sexual-side-effects-warning-to-baldness-drug-propecia/

  4. U.S. Food and Drug Administration, Questions and Answers: Finasteride Label Changes, http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm299754.htm