Effect of pentoxifylline on semen parameters, reproductive hormones, and seminal plasma antioxidant capacity in men with idiopathic infertility: a randomized double-blind placebo-controlled study

To determine the safety and efficacy of oral pentoxifylline (PTX) administration in improving semen parameters in infertile men with idiopathic OAT. The study included 254 infertile men who underwent double-blind therapy with 400 mg PTX (Apotex Inc., Toronto, Canada) twice daily (group 1, n = 127), or similar regimen of placebo (group 2, n = 127). The study consisted of a 4-week screening phase, a 24-week treatment phase, and a 12-week treatment-free period. The effects of treatment on semen parameters, serum hormones including testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and inhibin B, seminal plasma catalase-like and superoxide dismutase (SOD)-like activity, and acrosome reaction test were evaluated. A significant increase in sperm concentration (mean value, 26.4 +/- A 4.6 x 10(6)/ml vs. 16.2 +/- A 3.4 x 10(6)/ml), sperm motility (mean value, 35.8 +/- A 4.2% vs. 26.4 +/- A 2.4%), and sperm with normal morphology (mean value, 25.4 +/- A 4.3% vs. 17.4 +/- A 4.2%) was observed after PTX administration when compared with baseline (all P = 0.001); in contrast, a subtle decreased values were observed after placebo (median values, 16.4 +/- A 4.1 x 10(6)/ml vs. 16.7 +/- A 3.6 x 10(6)/ml, P = 0.1; 25.7 +/- A 3.6% vs. 26.8 +/- A 2.5%, P = 0.08; and 16.9 +/- A 4.1% vs. 17.6 +/- A 4.4%, P = 0.08, respectively). Mean SOD-like and catalase-like activity in the semen of PTX group was significantly greater than in the semen of placebo group (46.4 +/- A 2.4 vs. 36.3 +/- A 1.3 U/ml and 371 +/- A 44 vs. 301 +/- A 14 U/ml, respectively, both P = 0.003). The acrosome reaction was observed to be increased in PTX group (P = 0.01). Levels of reproductive hormones were also affected. PTX administration significantly improves semen parameters in infertile men with idiopathic OAT.