A review of 34 clinical trials on a popular drug to treat hair loss in men found that none of the studies adequately reported on the drug’s sexual side effects.
The findings raise serious questions about whether finasteride, marketed as Propecia and Proscar, among other names, is safe, according to the report by scientists at Northwestern University, published in the Journal of the American Medical Association (JAMA) Dermatology last week, Yahoo News reports.
The drug, received Food and Drug Administration (FDA) approved in 1992. It works by interfering with testosterone. Drug maker Merck lists decreased sex drive, impotence and problems with ejaculation among the drug’s common side effects. The JAMA study said these side effects have not been properly studied. “Not one of the 34 published clinical trial reports provided adequate information about the severity, frequency or reversibility of sexual adverse effects,” the study reports, according to Yahoo News.
Key questions have not been answered, the researchers say, including what is the actual risk of developing sexual side effects; how long they may last; how severe they are; and whether sexual function returns to normal if the drug is stopped. Most published studies on drug safety had a duration of one year or less, but about a third of men took the drug for more than a year, Yahoo News reports.
Lead author Steven Belknap, research assistant professor of dermatology and general internal medicine at Northwestern University Feinberg School of Medicine, said, “People who take or prescribe the drug assume it’s safe, but there is insufficient information to make that judgment.” He says there is inadequate information about the severity and frequency of sexual side effects, and he wonders whether such information was obtained then not included in the published articles. “Or, were these clinical trials performed in a way that simply didn’t capture this essential information?” Belknap asks, “[I]s the risk to benefit ratio of finasteride acceptable?”
The report was based on a meta-analysis that includes data from more than 5,700 men taking finasteride. Merck claims it conducted “well-designed clinical trials” and the company said it stands behind the results, which, Merck says, were reported to the FDA and regulatory agencies in other countries, according to Yahoo News.
An editorial accompanying the article calls for improved study of a drug’s potential harms, not just potential benefits, in clinical trials. “The international standard for the duration of clinical testing for non-life-threatening diseases requires that only 300 patients be observed for one year or more, and not necessarily with a comparison group,” wrote Thomas Moore of the Institute for Safe Medication Practices. He said this standard is “not adequate and should be reassessed.”
A wrongful death lawsuit filed last month in federal court in California alleges Merck hid the risks of depression and suicide among men taking finasteride. The suit was filed by the widow of a man killed himself in March 2013 after battling depression, insomnia, weight gain, and suicidal thoughts that persisted even after he stopped taking the drug, according to Law360.