In June 2011, the FDA updated the warning labels of both Proscar and Propecia to say that it may increase the risk of high-grade prostate cancer, the more serious type.
No clear causal relationship
Last year, the labels of both drugs were also revised to include erectile dysfunction that continued after patients stopped using the drugs.
In expanding the warning labels, the agency noted on its website that even though “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.”
It also tells Reuters that only a small percentage of men who use the drugs have experienced sexual side effects. For instance, an analysis of clinical trials showed that compared with 2.1 percent of those who received a placebo, 3.8 percent of men taking Propecia reported one or more of the sexual side effects.
Safe for approved uses
FDA also tells Reuters that it believes finasteride remains safe and effective for its approved uses. Patients on Proscar and Propecia should contact their doctors if they have concerns, the agency says.
In a statement sent to AFP, drugmaker Merck says, “Propecia and Proscar are generally well tolerated and effective for their respective intended uses in accordance with their approved product labeling.”
It also says, “a causal relationship between the use of Propecia or Proscar and continued sexual dysfunction after discontinuation of treatment has not been established” — and expressed support for ongoing monitoring of adverse event reports.
Meta-analysis shows impotence, other sexual Finasteride side effects
But a meta-analysis of previous research done last March by Boston University School of Medicine researchers found that finasteride and another drug used to treat hair loss or an enlarged prostate, dutasteride (Avodart), caused sexual dysfunction — including erectile dysfunction and loss of libido.
The meta-analysis also showed that finasteride side effects also include mental depression. The findings were published in the March 2011 issue of the Journal of Sexual Medicine.
The Boston University investigators found:
• Compared with four percent of men taking a placebo, eight percent of men taking finasteride and dutasteride reported erectile dysfunction.
• Compared to 1.8 percent of men receiving placebo, 4.2 percent reported reduced libido.
• In a small percentage of cases, sexual dysfunction and depression persisted even after the meds were stopped.
According to lead researcher Dr. Abdulmaged M. Traish, a professor of biochemistry and urology at the Boston University School of Medicine, almost all men who take these drugs to treat thinning hair will experience some of these distressing side effects — only the intensity varies. “Some experience it more drastically than others,” he claims.
Finasteride Side Effects: Decreased Libido and Potency posted 11 April 2015. Last update on 11 April 2015.