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New applications

Published in Efficacy
Tags: PDE5, tadalafil

New applications

Recent data have indicated a potential association between epidemiological, physiologic, pathophysiologic, and treatment aspects of ED and lower urinary tract symptoms (LUTS) secondary to BPH. The 17.5 hour half-life of tadalafil makes it the most suitable PDE5 inhibitor for once-daily dosing in a trial of LUTS secondary to BPH. McVary and associates reported a multicentered, randomized, double-blind, placebo controlled study of 281 men with LUTS secondary to BPH who were randomly assigned to once-daily tadalafil 5 mg for 6 weeks, followed by dose escalation to 20 mg for 6 weeks, or 12 weeks of placebo. They reported modest decreases in International Prostate Symptom Score (IPSS), with a mean change from baseline to 6 weeks of −2.8 with tadalafil 5 mg versus −1.2 with placebo (p < 0.003), and to 12 weeks of −3.8 with tadalafil 5/20 mg versus −1.7 with placebo (p < 0.001).

To further examine the efficacy and dose response of tadalafil professional in men with LUTS secondary to BPH, Roehrborn and colleagues performed a similar multicentered, randomized, double-blind, placebo controlled study with a larger sample size and different tadalafil doses. The 1058 men with LUTS secondary to BPH in the study received once-daily placebo or tadalafil (2.5, 5, 10 or 20 mg) for 12 weeks. The IPSS mean change from baseline to endpoint after 12 weeks was significantly improved, –3.9 for tadalafil 2.5 mg (p <0.015), −4.9 for tadalafil 5 mg (p < 0.001), −5.2 for tadalafil 10 mg (p < 0.001), and −5.2 for tadalafil 20 mg (p < 0.001), compared with −2.3 for placebo. The optimal risk-benefit profile for men with LUTS secondary to BPH was achieved with the tadalafil 5 mg dose (Roehrborn et al 2008).

These observations may be a result of increased cGMP causing a decrease in prostatic muscle tension, NO effect on the smooth muscle of the bladder, PDE inhibition in the prostate and prostatic urethra, or some other process not yet defined. Further basic science and clinical research is necessary to define the role of tadalafil’s effect on the bladder, the prostate, and LUTS.