Researchers say that Eli Lilly’s erectile dysfunction drug Cialis helps reduce the symptoms caused by enlarged prostates.

The study, published in The Journal of Urology, concludes that men with signs of benign prostatic hyperplasia can be helped with a daily dose of Cialis (tadalafil) to relieve associated lower urinary tract symptoms (LUTS). The researchers, from the University of Texas Southwestern Medical Center at Dallas, Northwestern University and Lilly Research Laboratories, base that conclusion on a randomised, double-blind, placebo-controlled study of 1,056 men in ten countries.

The men in the study were divided into five groups that received either a placebo or tadalafil doses of 2.5, 5.0, 10.0 or 20.0mg a day. All doses of the drug were superior to a placebo for relieving LUTS, with statistically significant effects at four, eight and 12 weeks.

One of the lead authors of the study, Claus Roehrborn, said that since reports of ED incidence, pathophysiology and treatment have shown a possible link between enlarged prostate and the disease. Phosphodiesterase type 5 inhibitors like Cialis have received increased attention for treating BPH LUTS, although they are currently only approved for ED, but the half-life of tadalafil is 17.5 hours, he said, making it suitable as once-daily therapy.

Prof Roehrborn added that “although the precise mechanism of action by which PDE5 inhibitors may alleviate LUTS is not completely understood, several putative mechanisms are currently under investigation”.

Men with signs of BPH may experience LUTS, such as urinary frequency, urgency, intermittence, nocturia, straining, incomplete emptying or a weak urinary stream, with an overall prevalence of greater than 50% in men 50 years or older. The researchers noted that drugs currently used to treat these symptoms can produce dizziness, low blood pressure and sexual dysfunction.