The new horizons of pharmacotherapy. Unexpected pharmacological actions and a new therapeutic strategy of phosphodiesterase–5 inhibitors

INTRODUCTION: Benign prostate hyperplasia and erectile dysfunction affect a significant subset of men. BPH and ED may have the same promoting conditions and are the strong predicting risk factors to each other. A significant number of these patients are bothered by lower urinary tract symptoms (LUTS). Direct correlation of age, sexual dysfunction and LUTS severity has been well documented. Many sexually dysfunctional patients with concomitant BPH receive alpha–adrenergic antagonists and any Phosphodiesterase–5 (PDE5) inhibitor simultaneously. PDE5 inhibitors relieve LUTS symptoms in the course of BPH and reduce independent detrusor contractions. This paper presents the results of clinical trials on the efficacy of PDE5 inhibitors on LUTS, new perspectives on its use and newly–identified side effects. MATERIAL AND METHODS: The review is based on an internet search of PubMed and Medscape databases. The search terms were as follows: LUTS and ED, BPH and phosphodiesterase–5 inhibitors, LUTS clinical trials, phosphodiesterase–5 inhibitors mechanisms. RESULTS: Clinical trials show an epidemiological and pathophysiological relationship between BPH, LUTS and ED. Numerous studies reveal the alleviating effect of phosphodiesterase–5 inhibitors on LUTS, expressed as the reduction of IPSS score, but not followed by a change in Qmax. Opponents raise a link of PDE5 inhibitors with increased risk of melanoma. New studies reveal that phosphodiesterase–5 inhibitors are effective in the treatment of neurological disorders. CONCLUSIONS: Researches reveal the efficacy of phosphodiesterase–5 inhibitors in LUTS along with an improvement of erectile function. The molecular mechanism of action of such drugs suggests imminent novel applications. Potential benefits will be multidimensional. Unfortunately, interfering with particular molecular mechanisms may alleviate some diseases, but may lay groundwork for others – new and even more devastating.