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

The Role of PDE5 Inhibitors in the Treatment of Testicular Dysfunction

“…Thus a direct effect of sildenafil on sperm flagella cannot be ruled out (Nomura & Vacquier, 2006). Interestingly, the study by Pomara et al, (2007) revealed a significant decrease in the sperm motility after a single dose of tadalafil (Pomara et al, 2007). These latter findings are inconsistent with an earlier study conducted by Hellstrom and colleagues (2003) who investigated the effects of tadalafil on semen characteristics and serum concentrations of reproductive hormones in healthy men and men with mild erectile dysfunction.…”

“…On the other hand the authors have noticed that long time sildenafil treatment is associated with a significant decrease in total sperm output and sperm concentration. Pomara et al, (2007) performed a prospective, double-blind, randomized, crossover study describing the acute effect of both sildenafil (50 mg) and tadalafil (20 mg) in young infertile men. Eighteen young infertile men were asked to ingest a single dose of either sildenafil or tadalafil in a blind, randomized order.…”

“…In addition, the authors demonstrated that there were no significant alterations in the serum levels of reproductive hormones after tadalafil administration concluding that administration of tadalafil at doses of 10 mg and 20 mg for six months did not adversely affect testicular spermatogenesis process or serum levels of reproductive hormones. However other investigators have emphasized their dilemma concerning the administration of tadalafil on a daily basis, as they believe that up today the available data confirming the safety of tadalafil administered on a daily basis are not yet adequate (Pomara et al, 2007). Taking in consideration the above dilemma Hellstrom et al, (2008) expanded their investigation efforts in a double-blind, placebo-controlled, noninferiority study, assessing the effects of tadalafil (20mg) on spermatogenesis over three spermatogenesis cycles in men elder than 45-year-old.…”

Oral phosphodiesterase-5 inhibitors and sperm functions

“…du Plessis et al 27 demonstrated various increased kinematical parameters on 20 healthy volunteers after treatment with 50 mg of sildenafil, with a significant increase in the population of rapid cells in semen samples collected 1 h later. Pomara et al 42 observed a significant increase in sperm progressive motility after 50 mg sildenafil dose, compared with baseline, and a significant decrease after 20 mg tadalafil dose evaluated after 1 or 2 h in a prospective randomized, double-blind, crossover study on 18 young infertile men.…”

Phosphodiesterases in endocrine physiology and disease

“…In a clinical trial, daily intake of tadalafil at doses of 10 and 20 mg for 6 months produced no change in spermatogenesis or reproductive hormones in men (46). Another study demonstrated that tadalafil causes a statistically significant decrease in sperm motility (47). In mice, it was shown that chronic overexposure to tadalafil causes testicular tissue alterations with decreased testis weight, degeneration, and atrophy of the seminiferous epithelium and decrease in sperm production.…”