Chronic Sildenafil Improves Erectile Function and Endothelium-dependent Cavernosal Relaxations in Rats: Lack of Tachyphylaxis

This is the first report providing experimental support for chronic dosing with sildenafil which could be of use for patients that are poor responders to on-demand treatment. Chronic sildenafil may regulate the transduction pathway leading to the activation of eNOS but has no effect on NO bioavailability or on the cGMP pathway, thereby eliminating a possible concern for tachyphylaxis.