Researchers from Brigham and Womenâ€™s Hospital in Boston found that reports of these negative drug side effects among men ages 45 or younger rose significantly after 2012.
Data for the study came from a World Health Organization database of drug safety reports from over 150 countries.
Strong link between drug and symptoms
However, these types of studies are less rigorous than a placebo-controlled clinical trial, so the results should be viewed with some caution.
â€œIt is important to note that observational studies, such as this, cannot establish that finasteride causes these adverse events,â€ said Shelly Gray, PharmD, a professor at the University of Washingtonâ€™s School of Pharmacy.
Although researchers found a strong link between the drug and suicidality and psychological symptoms, there are several possible explanations for the results.
There could be a biological explanation for how the drug causes these symptoms.
Or, men with hair loss, also known as alopecia, may have other factors or health problems that increase their risk of suicidality, depression, or anxiety.
Gray said increased media attention of the drugâ€™s possible side effects may have also resulted in more men reporting their symptoms.
Additional research is needed to fully understand the link between the drug and the symptoms experienced by younger men.
Finasteride was developed to treat benign prostatic hyperplasia, a noncancerous enlargement of the prostate. Its use was later extended to treat male pattern hair loss.
In the new study, researchers identified 356 reports of suicidality, and almost 3,000 reports of other psychological symptoms among men taking finasteride.
Most of these occurred in men who were 45 years or younger, and among those who were taking finasteride for hair loss.
No strong link between the symptoms and the drug were seen in older men taking the drug for an enlarged prostate.
Drug effective for treating prostate enlargement
Dr. Brian Norouzi, a urologist with St. Joseph Hospital in Orange County, California, said finasteride has been a controversial drug for almost as long as itâ€™s been on the market.
The Food and Drug Administration (FDA) approved the drug in 1997.
â€œInitially, its potential effects on erections scared many patients away, except for older men or those that had few other nonsurgical options,â€ he said.
However, finasteride can be an effective treatment for some older men with benign prostatic hyperplasia (BPH).
â€œIt can really help men with super-large prostates, for which our office procedures have lower success rates, and for whom more aggressive surgery might be necessary without the drug,â€ said Norouzi.
When the prostate enlarges, men can have difficulty urinating. By reducing the size of the prostate, finasteride can help men regain the ability to urinate without the need for surgery.
For treating BPH, finasteride is sometimes used in combination with doxazosin (Cardura), which is in a class of drugs called alpha-blockers.
Given the effectiveness of finasteride in shrinking the prostate, Norouzi said he will continue to recommend the drug for his patients. But he thinks men should be aware of the potential side effects.
â€œWhether the risks outweigh the benefits is an individual determination, as finasteride has also been known to potentially cause erectile dysfunction and loss of libido,â€ said Norouzi. â€œStill, it is a commonly used medicine by many patients.â€
Gray agreed that men who want to try finasteride for hair loss should be told of the risks, especially younger men who appear to be at higher risk of negative side effects.
â€œProviders should counsel their patients about the possibility of sexual, physical, and psychological adverse events during treatment,â€ said Gray.
Some patients continue to experience these symptoms after they stop using the drug, she said, although physicians arenâ€™t sure why that occurs.
If younger men choose to use the drug for hair loss, they should contact their doctor if they experience any side effects, especially thoughts of suicide.
â€œWhen a patient is started on finasteride for alopecia, providers should periodically monitor for depression, anxiety, and suicidal ideation,â€ said Gray.
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