Tadalafil Shows Promise for Relief of Lower Urinary Tract Symptoms Associated with Benign Prostatic Hyperplasia

Researchers from the University of Texas Southwestern Medical Center at Dallas, Northwestern University and Lilly Research Laboratories report on a randomized, double-blind, placebo-controlled study of over 1000 men in ten countries.

Claus G. Roehrborn, MD, Professor of Urology, University of Texas Southwestern Medical Center, states, “Since reports of erectile dysfunction (ED) incidence, pathophysiology and treatment have shown a possible link between BPH LUTS and ED. PDE5 inhibitors like tadalafil (Cialis®) have received increased attention for treating BPH LUTS, although they are currently only approved for ED. The half-life of tadalafil is 17.5 hours, making it suitable as once daily therapy. 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. LUTS increase with age with an overall prevalence of greater than 50% in men 50 years or older. Drugs currently used to treat these symptoms can produce unwanted side effects, including dizziness, low blood pressure and sexual dysfunction.

Participants in the tadalafil study were required to have at least a 6-month history of LUTS secondary to BPH. Subjects with a high PSA (more than 10 ng/ml) were excluded, as were subjects with other complicating conditions or conflicting drug treatments. Anyone who had undergone treatment for erectile dysfunction or other BPH treatments underwent a 4-week treatment-free screening period. All participants then received placebo for 4 weeks prior to randomization. The 1056 subjects were then divided randomly into 5 groups that received a placebo, or doses of 2.5, 5.0, 10.0 or 20.0 mg/day of tadalafil.

Using the International Prostate Symptom Score (I-PSS), a validated seven-item questionnaire about LUTS occurring within the last month, the researchers found that all doses of tadalafil were superior to placebo for relieving LUTS, with statistically significant effects at 4, 8 and 12 weeks. The treatments decreased I-PSS scores from 3.9 to 5.2 points in the different dosage groups, a clinically meaningful improvement according to the guidelines of the American Urological Association. Of the doses studied, 5 mg per day improved the I-PSS by 4.9 points and provided the best risk-benefit profile.

The article is “Tadalafil Administered Once Daily for Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia: A Dose Finding Study” by Claus G. Roehrborn, Kevin T. McVary, Albert Elion-Mboussa and Lars Viktrup. It appears in The Journal of Urology, Volume 180, Issue 4 (October 2008) published by Elsevier.