Abstract
BACKGROUND: Erectile dysfunction (ED) is a common nonmotor feature in patients with Parkinson's disease (PD). Data regarding the tolerability and efficacy of anti-ED medication in the PD population are limited. The aim of this work was to assess the safety and efficacy of sildenafil in treatment of ED in men with PD. METHODS: This was a double-blind, placebo-controlled, cross-over study consisting of two 4-week arms separated by a 2-week washout period. Treatment sequence (placebo-sildenafil vs. sildenafil-placebo) was randomized. Sildenafil was started at 50 mg and adjusted to 25, 50, or 100 mg after 2 weeks, depending upon side effects. The Erectile Function domain of the International Index of Erectile Function (IIEF-EF; primary outcome measure) and the Parkinson's Disease Quality of Life (secondary outcome measure) were obtained at baseline and end of each treatment period. The UPDRS was obtained at each study visit. The difference between group means was tested for statistical significance using t tests. RESULTS: Twenty men participated and completed both treatment arms of the study. There was one instance of headache as a side effect. There was a significant effect of sildenafil on sexual functioning as measured by the IIEF-EF domain (P < 0.0001; mean for sildenafil = 23.2 ± 7.0; mean for placebo = 12.3 ± 7.5). There were no treatment effects for quality of life (P = 0.3) or PD symptoms (P = 0.86). CONCLUSIONS: Sildenafil was safe and improved ED in this sample of men with PD. Overall, PD symptoms and quality of life were not impacted by use of sildenafil.