Impact of Dry Ejaculation Caused by Highly Selective α1A-blocker: Randomized, Double-blind, Placebo-controlled Crossover Pilot Study in Healthy Volunteer Men

Abstract

INTRODUCTION: Dry ejaculation with loss of seminal emission is reported in patients who have been administered silodosin, an alpha1A-adrenoceptor antagonist. AIM: We investigated the impact of dry ejaculation caused by orally administered silodosin on orgasmic function. METHODS: In a double-blind crossover study, 50 healthy volunteer men were randomly assigned to receive either a single dose of 4-mg silodosin or placebo with 3 days of washout before crossover. Subjects masturbated 4 hours after administering agents. MAIN OUTCOME MEASURES: Numerical rating scale (NRS) score from 0 (highest) to 10 (lowest) for subjective quality of orgasm, the subjective number of contractions of the bulbocavernosus/pelvic floor muscles, and the amount of semen were examined. Results. After the administration of silodosin, the NRS score worsened by 1.3 points (P = 0.003), the number of contractions of the bulbocavernosus/pelvic floor muscles decreased by about 1 (P = 0.003), and there was a decrease of 1.8 mL in the amount of semen produced (P < 0.0001). Eleven men overall (22%) on silodosin administration had less than a 50% decrease from baseline in the amount of semen. CONCLUSIONS: Silodosin may adversely affect the subjective orgasmic function by causing an abnormal ejaculation with decreased (or no) semen discharge and a decrease in the number of bulbocavernosus/pelvic floor muscle contractions. Semen passing through the urethra and sufficient rhythmic contraction of the muscle of the pelvic floor may contribute to the subjective pleasure of orgasm.