Older men taking a 5α-reductase inhibitor (5ARI) such as Avodart (dutasteride) and Proscar (finasteride) for prostate enlargement are “significantly” more likely to hurt themselves and suffer from depression — but not commit suicide, a new study shows.

“The relatively small magnitude of these risks should not dissuade physicians from prescribing these medications in appropriate patients,” said researchers, whose study, “Association of Suicidality and Depression With 5α-Reductase Inhibitors,” appears in JAMA Internal Medicine.

Benign prostatic hyperplasia (BPH) is a major cause of lower urinary tract symptoms (LUTS) that plague roughly 25 percent of men over 70.

U.S., Canadian and European urology societies recommend a 5ARI as medical therapy for BPH-related LUTS. Avodart, Prosper and other 5-Alpha-reductase inhibitors block the action of 5-alpha-reductase, the enzyme that converts testosterone into dihydrotestosterone — which has greater affinity for androgen receptors and is much more powerful than testosterone. The activity of 5ARIs boost testosterone levels while reducing levels of dihydrotestosterone.

However, doctors have raised concerns about the adverse psychiatric adverse effects of 5ARI use such as depression, self-harming behavior and suicide that 5ARIs may cause. In this context, a team of researchers led by Blayne Welk, MD, of Canada’s Western University conducted a population-based study of 93,197 older men (66 or older) in Ontario province who had begun new 5ARI prescriptions for BPH between 2003 and 2013.

Researchers then compared these men with a matched group of men not taking a 5ARI. They found no significant increase in suicide risk among those taking 5ARIs, but did see a “significant” increase in risk of self-harm in the first 18 months of treatment, then falling back to normal levels after treatment stopped. Likewise, the risk of depression also rose during the initial 18 months, and continued to be elevated — but to a lesser degree — for the remainder of the foll0w-up period.

Nevertheless, researchers concluded that “the absolute increased risk of these two outcomes was low, and the potential benefits of 5ARIs in this population likely outweigh these risks for most patients.”