The results of a new study conducted at the Feinberg School of Medicine a Northwestern University in Chicago indicate that men who take either of the two drugs in the 5-alpha-reductase inhibitor category (Proscar and Avodart) are at greater risk of experiencing persistent erectile dysfunction (PED) after they stop using the drugs. Therefore, it appears that Proscar and Avodart cause ED, at least to some degree.
Proscar (generic, finasteride) is used to treat enlarged prostate, or benign prostatic hyperplasia, BPH), Propecia (also finasteride) is used to treat male pattern hair loss. Avodart (generic, dutasteride) is prescribed to treat BPH.
Persistent ED was defined as erectile dysfunction lasting 90 days or longer. Of the 691,268 men aged 16 to 89 who were evaluated in the study, about half (327,437) were young (16 to 42 years). Of the 7,475 men who had taken either of the drugs, 89.5 percent had not experienced ED or low sex drive in the past. Also in this group, 4.5 percent developed new ED and 1.3 percent developed new low libido.
Among the younger men, persistent ED developed in 0.79 percent of 4,284 who took finasteride (1.25 mg/day or less) who had no previous problem with sexual function. Their erectile dysfunction lasted for a median of 1,534 days after they stopped taking the drug. Younger men who took finasteride for more than 205 days showed a 4.9-fold higher risk of persistent ED when compared with men who took the drug for a shorter length of time.
According to the authors of the study, among younger men who have taken 5-alpha reductase inhibitors, the length of time they used the drugs was a more accurate predictor of developing persistent ED than all other assessed risk factors.
The study’s authors concluded that their finding of an association between exposure to Proscar or Avodart and persistent erectile dysfunction “will be of particular interest to prescribers and patients considering medical management of androgenic alopecia or symptomatic treatment of prostatic hyperplasia.” If you are thinking about taking either Proscar or Avodart, talk to your doctor about this possible side effect.
Read more in our Erectile Dysfunction Health Center.
Kiguradze T et al. Persistent erectile dysfunction in men exposed to the 5a-reductase inhibitors, finasteride, or dutasteride. PeerJ 2017 Mar 9