Phosphodiesterase-5 inhibitors may improve prostatic hyperplasia

Last Updated: 2007-01-08 11:14:30 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Preclinical results suggest that phosphodiesterase (PDE)-5 inhibitors might be useful for treating symptoms associated with benign prostatic hyperplasia (BPH), according to a report in the December BJU International.

Preliminary evidence suggests that PDE inhibition can relax human prostate tissue, the authors explain, but whether PDE-5 inhibitors could be useful in treating BPH has not been studied.

Hanna Tinel and colleagues from Bayer Health Care AG, Wuppertal, Germany investigated the effect of the PDE-5 inhibitors sildenafil, vardenafil, and tadalafil in in vitro tissue studies and an in vivo rat model of bladder outlet obstruction.

All three PDE-5 inhibitors induced relaxation of bladder strips and reduced contraction of rat prostate strips and urethral rings, the authors report. Vardenafil was the most potent of the three compounds.

The PDE-5 inhibitors also significantly induced the proliferation of human stromal cells, mainly responsible for prostatic hypertrophy in BPH, the results indicate.

Given intravenously, vardenafil and sildenafil significantly reduced non-voiding contractions in a rat model, whereas tadalafil was ineffective, the researchers found. "Thus," they say, "sildenafil and vardenafil can reduce irritative symptoms of BPH in the rat at a minimum effective dose of 3 mg/kg."

"Taken together, the present results show that PDE-5 inhibitors might minimize obstructive symptoms of BPH via dilatation of the prostate and urethra, and by inhibiting prostate growth," the Bayer group concludes. "In addition, PDE-5 inhibition could reduce irritative symptoms of BPH, by reducing non-voiding contractions in the hypertrophied bladder."

They therefore conclude that "PDE-5 inhibitors, beyond their efficacy in erectile dysfunction, might be also used for the therapy of BPH/LUTS."

BJU International 2006;98:1259-1263.