The toxic effect of opioid analgesics on human sperm motility in vitro.

Opioid analgesics are the most common therapeutic analgesic for acute pain. In this study, the toxicological and pharmacological features of a group of opioid analgesics were characterized by the motility of human sperm. Aliquots of sperm were incubated with various concentrations of opioid analgesics in vitro. Computer-assisted sperm analysis was used to assess sperm motility at 15 minutes, 2 hours, and 4 hours after drug addition to the medium. Butorphanol and dezocine showed marked reduction of motility after incubation with sperm for 15 minutes. Butorphanol was more effective than dezocine in immobilizing sperm. Other opioids studied, such as fentanyl, alfentanil, and sufentanil, showed only partial inhibitory activity. Based on the data reported herein, we have found that butorphanol and dezocine exert a sperm-immobilizing effect. However, fentanyl, alfentanil, and sufentanil exhibit only partial inhibition of sperm motility. Given the increasing use of opioids and their potential effect on sperm motility, these findings are greatly relevant to male reproductive health.