Alterations in sperm motility after acute oral administration of sildenafil or tadalafil in young, infertile men

Objective To evaluate the acute effect of sildenafil and tadalafil on seminal parameters in young, infertile patients. Design Prospective, randomized, double-blind, crossover clinical investigation on semen parameters after the administration of a single dose of sildenafil (50 mg) or tadalafil (20 mg). Setting An academic hospital as well as a male infertility center and clinical andrology laboratories. Patient(s) Eighteen young, infertile men. Intervention(s) Oral administration of a single dose of sildenafil (50 mg) or tadalafil (20 mg) in a blind, randomized order. The semen samples were collected 1 or 2 hours after each treatment. Main Outcome Measure(s) Changes in sperm parameters after sildenafil and tadalafil administration, compared with the basal conditions. Result(s) A significant increase in sperm progressive motility (median value, 37.0% vs. 28.5%) was observed after sildenafil administration as compared with baseline; in contrast, a significant decreased value was observed after tadalafil (median value, 21.5% vs. 28.5%). Conclusion(s) These preliminary results indicate that sperm motility appears to be acutely affected in young, infertile patients by a single dose of sildenafil and tadalafil, with opposite effects: stimulatory by the former and inhibitory by the latter.