Treatments for erectile dysfunction may prove effective against benign prostatic hyperplasia and lower urinary tract symptoms, possibly because they share a common etiologic pathway.

Studies involving all three of the currently available type 5 phosphodiesterase (PDE5) inhibitors showed improvement in Benign prostatic hyperplasia (BPH) and urinary symptoms, regardless of whether the patients had concomitant erectile dysfunction. The three studies, two from the U.S. and one from Germany, were reported at the American Urological Association meeting.

The data reinforce an emerging theoretical and scientific framework that posits a common pathway for development of erectile dysfunction, benign prostatic hyperplasia, and lower urinary tract symptoms, and, the research suggests, possibly overactive bladder, researchers said.

The larger of the two prospective, randomized trials was conducted by Kevin McVary, M.D., of Northwestern University, and colleagues. It involved 369 men who had erectile dysfunction and concomitant lower urinary tract symptoms.

The patients, whose mean age was 60, had about a six-year history of erectile dysfunction and a five-year history of BPH and lower urinary tract symptoms. They were randomized to placebo or to 50 mg of sildenafil (Viagra) taken nightly before bedtime or 1 hour before sexual activity.

Treatment continued for 12 weeks. The primary endpoints were change in the erectile function (EF) domain score of the International Index of Erectile Function, change in the International Prostate Symptom Score (IPSS), and change in maximum urinary flow (Q_max).

Overall, patients treated with sildenafil had a 6.32-point improvement in the IPSS compared to 1.93 for the placebo group (P<0.001). EF domain scores improved by an average of 9.17 in the sildenafil group and 1.86 in the placebo group (P<0.001). Q_max did not differ between groups at baseline or at the end of the study.

Stratification of the data by baseline severity showed that patients with severe (IPSS ¡Ý20) lower urinary tract symptoms improved substantially more compared with placebo than did those with moderate (IPSS 8-19) symptoms (P=0.0619). Among men with severe symptoms at baseline (54% of the cohort), substantially more had mild (16% vs. 4%) or moderate (57% vs. 36%) symptoms compared with placebo at the end of the study, the researchers found.

"The improvement in IPSS correlated with the IIEF changes," said Dr. McVary said. "Patients with more severe symptoms had more improvement, in a sense because they have more room for change."

He noted, however, that the researchers were surprised to find that the improvement did not correspond with the flow rate. "Although we didn't have an active comparator, the improvement looks to be comparable to what we might expect when giving alpha-blockers or a five-alpha reductase inhibitor," he said.

Asked to speculate about the lack of correlation between symptom improvement and flow rate, Dr. McVary said he and his colleagues initially suspected a predominance of urgency symptoms as opposed to obstruction. However, the data showed that both types of symptoms improved to a similar degree.

With respect to potential mechanisms involved in the co-existence of lower urinary tract symptoms and erectile dysfunction and the lack of flow improvement, Dr. McVary said that a pelvic deficiency in nitric oxide remains a viable explanation.

Other possibilities, he said, include an effect on bladder compliance, modulation of potential PDE5 effects on sensory innervation, and perhaps a change in pelvic flow affecting ischemia.

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Source: Medpagetoday