Comparison of the efficacy and safety of sildenafil citrate (Viagra) and oral phentolamine for the treatment of erectile dysfunction.

This open-label, multi-center study from Mexico compared the efficacy and safety of oral sildenafil and phentolamine in men with erectile dysfunction. Patients received sildenafil (25-100 mg; n=123) or phentolamine (40 mg; n=119) for 8 weeks, and efficacy was assessed using the International Index of Erectile Function (IIEF) as well as two global efficacy questions. Mean scores for the erectile function domain of the IIEF were significantly higher for sildenafil (27.23 +/- 0.62; P=0.0001) than for phentolamine (19.35 +/- 0.66). Approximately twice as many men receiving sildenafil had successful attempts at sexual intercourse (88% vs 42%), improved erections (95% vs 51.1%), and improved ability to have sexual intercourse (94.4% vs 46.4%) compared with phentolamine. The most common adverse events included rhinitis, headache, tachycardia, and nausea, with a higher frequency reported in patients receiving phentolamine than sildenafil (41% vs 33%), with the exception of headache, which was reported more frequently in sildenafil users. Overall, sildenafil was more effective and appeared to be better tolerated than phentolamine for the treatment of erectile dysfunction.