Safety and efficacy of the combination of once-daily tadalafil and alpha-1 blocker in Japanese men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia: A randomized, placebo-controlled, cross-over study

Abstract

Objectives: To evaluate the safety and efficacy of tadalafil plus α₁ -blocker combination therapy in Japanese patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

Methods: The present multicenter, randomized, double-blind, placebo-controlled, two-period cross-over study compared the effects of tadalafil and a placebo added to ongoing α₁ -blocker therapy. A total of 171 Japanese patients were randomized.

Results: Tadalafil combined with an α₁ -blocker did not decrease blood pressure in the orthostatic test. The only statistically significant differences in vital signs between the combination and monotherapy groups were diastolic blood pressure and pulse (P = 0.0194 and 0.0313, respectively). However, these changes were not considered clinically meaningful. Treatment-related adverse events occurred in 28.1% (47/167) and 24.2% (39/161) of patients in the combination therapy and α₁ -blocker monotherapy groups, respectively. Additionally, 56.7% (89/157) of patients preferred combination therapy to monotherapy, though this was not statistically significant (P = 0.0937). There was a statistically significant reduction in the International Prostate Symptom Score voiding subscore in the combination therapy group (P = 0.0442).

Conclusions: Concurrent treatment with tadalafil and an α₁ -blocker seems to be safe and well tolerated in Japanese patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. Adding tadalafil to baseline α₁ -blocker therapy does not translate in adverse effects on the blood pressure. Patients tend to prefer combination therapy over monotherapy, and there seems to be a clinical benefit when using combination therapy.

Keywords: adrenergic alpha-1 receptor antagonists; benign prostatic hyperplasia; hypotension; lower urinary tract symptoms; tadalafil.