Does sildenafil enhance quality of nocturnal erections in healthy young men? A NPT-RigiScan™ study

Objective. To assess the effect of sildenafil on nocturnal erectile function (EF) in young healthy volunteers with normal sexual function (SF) according to the International Index of Erectile Function (IIEF) questionnaire. Methods. Thirty-three young (mean age 21 ± 0.3 years; range 18-25) healthy volunteers not taking any medications who had normal SF and an EF domain >26 on the IIEF questionnaire were evaluated. Erectile function was assessed using the RigiScan™ (Dacomed Corp., MN, USA) during three nights: night 1 = adaptation to the NPT-Rigiscan apparatus, night 2 = baseline recording of eight parameters, and night 3 = recordings after ingestion of sildenafil 100 mg. Data on the number of erections, erection duration, minimal and maximal base tumescence, minimal and maximal tip tumescence, and base and tip rigidity were analysed using ANOVA with repeated measures. Results. A statistically significant improvement in all eight parameters was observed as a result of sildenafil administration: number of erections from 3.1 ± 0.7 to 4.0 ± 0.7 (P < 0.05), erection time 22 ± 3.5 to 34.2 ± 5.9, minimal base tumescence 8.2 ± 0.8 to 8.7 ± 0.8, maximal base tumescence 12.1 ± 0.7 to 14.2 ± 0.7, base rigidity 75.6 ± 3.1 to 81.6 ± 3.6, tip rigidity 70.6 ± 1.5 to 75.9 ± 3.1, minimal tip tumescence 5.9 ± 0.5 to 6.5 ± 0.6, and maximal tip tumescence 8.6 ± 0.6 to 11.7 ± 0.7 (P < 0.0001 for each of the last seven parameters). The mean sleep duration, 7.3 hours (range 6.30-9.20 hours), was similar for both nights of recording. Conclusions. Sildenafil increases the quality and number of nocturnal erections as tested by the NPT-RigiScan™ in young healthy volunteers with normal EF.