Effect of acute in vivo sildenafil citrate and in vitro 8-bromo-cGMP treatments on semen parameters and sperm function.

OBJECTIVE

To determine the effect of acute in vivo sildenafil citrate (VIAGRA) and in vitro 8-Bromo-cGMP treatments on semen parameters and sperm function.

DESIGN

Prospective double-blind, placebo-controlled, crossover, two-period clinical investigation.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S): Twenty male volunteers with normal erectile function and normal electrocardiogram were recruited.

INTERVENTION(S): In vivo: 50 mg of sildenafil citrate (VIAGRA) or placebo was administered p.o., and semen samples were collected 1 hour after administration of the test drug. In vitro: 8-Bromo-cGMP (20 microM; 60 minutes) was added to semen samples.

MAIN OUTCOME MEASURE(S): Macroscopic and microscopic seminal parameters were measured and motility studies performed. Various acrosome reaction studies and sperm-zona pellucida binding studies were also done.

RESULT(S): Either sildenafil citrate (VIAGRA) or 8-Bromo-cGMP treatments had no effect on both macroscopic and microscopic seminal parameters as well as the acrosome reaction. Sperm-zona pellucida binding results were however increased to 148.75% and 134%, respectively, by these treatments. Various kinematical parameters increased after treatment with the most significant increase detected in the population of rapid cells.

CONCLUSION(S): VIAGRA can be used successfully to enhance sperm motility and binding to the oocyte especially during fertility treatments.