Certain common drugs prescribed for those suffering from male pattern hair loss and benign prostate enlargement (BPH) may lead to adverse sexual side effects such as loss of libido or erectile dysfunction, a new study has claimed.
Twenty-five per cent of men currently taking Finasteride or Dutasteride, popularly known as Proscar and Avodart, for the treatment of BPH, appear not to benefit from taking these medications, researchers said.
Those prescribed Propecia or Avodart for male pattern hair loss – known as alopecia – are also at risk for adverse events elicited by these drugs, they said.
Led by Abdulmaged Traish, professor of biochemistry and urology at Boston University School of Medicine (BUSM), the study summarises current available data and the impact of these drugs on sexual function as well as insulin resistance, depression and cognitive dysfunction.
Finasteride and Dutasteride are in the family of drugs known as 5a-reductase inhibitors (5a-RIs).
They function by inhibiting the conversion of testosterone to 5a-dihydrotestosterone (5a-DHT) as well as several other critical steroid hormones.
By reducing the concentration of 5a-DHT in the prostate, prostate volume decreases thus improving urinary flow.
Considerable controversy exists regarding the severity and persistence of the adverse effects of 5a-RIs, but emerging clinical evidence strongly suggests that therapy is associated with sexual adverse side effects.
The package insert for Finasteride reports a libido loss and/or reduction in 10 per cent of patients and erectile dysfunction in 18 per cent.
In some patients, these effects can remain even after stopping therapy. According to the researchers the suggestion that sexual side effects appear early in the first six months of therapy and then return to baseline is inaccurate.
“The mechanism of dysfunction is likely multifactorial, related both to the direct decrease in 5a-DHT and direct influence on central and peripheral nerves,” said Traish.
In addition to sexual side effects, there has been some investigation into whether 5a-RIs can be used for prostate cancer chemo-prevention, but the researchers found the data to be inconclusive.
They also believe the potential for cardiovascular side effects of therapy to warrant further investigation.
“Inhibition of 5a-R activity may potentiate insulin resistance, type 2 diabetes, vascular disease and osteoporosis, but studies have not been definitive,” said Traish.
“The investigation into psychiatric side effects of 5a-RIs has been limited, but some case series describe increased depression and anxiety symptoms among patients on the medication,” he added.
The findings were published in the journal Endocrine Reviews and Metabolic Disorders.