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.