Indomethacin and oxaprozin lower seminal prostaglandin levels but do not influence sperm motion characteristics and serum hormones of young healthy men in a placebo-controlled double-blind trial.

To evaluate the influence of indomethacin and oxaprozin on reproductive function in healthy young men, 34 volunteers with normal semen parameters were recruited. In a randomized double-blind design, 12 men were treated with placebo, 12 received 600 mg/day of oxaprozin and 10 took indomethacin 25 mg t.i.d. This treatment phase lasted for 14 days after which a follow-up period extended for another 10 weeks. Sperm counts, percentage of motile and normally formed sperm cells, sperm velocity, linearity, lateral head displacement and beat frequency were evaluated by computerized image analysis once before treatment and at weekly intervals during the rest of the study. Prostaglandin levels in seminal plasma were significantly reduced after 2 weeks of treatment and remained suppressed for at least 2 additional weeks. In spite of this long lasting impairment of physiologic prostaglandin concentrations, no changes in any of the measured parameters were detectable when compared with the placebo group. Basal levels of testosterone, estradiol, LH, FSH, TSH and prolactin were unchanged. The response of hypophyseal hormones to a combined GnRH/TRH test before, during and after the treatment also was not affected. Overall, no negative influence of indomethacin or oxaprozin treatment on male reproductive function could be found in healthy volunteers. Since the active treatment phase was only 14 days, one can only speculate about long term effects of the tested drugs on reproductive parameters in men.