OBJECTIVETo observe the effects of short-term exposure to opioid analgesics on human sperm motility.

METHODSTwenty normal semen samples were collected, each divided into 19 groups, one as the control and the others treated in vitro with six opioid analgesics at three different concentrations, respectively, and sperm motility was assessed by computer-assisted sperm analysis at 15 min, 2 h and 4 h.

RESULTSCompared with the control group, fentanyl, alfentanil and sufentanil at 1 x 10(-5), 2 x 10(-3) and 0.05 mg/ml significantly decreased the percentage of grade a + b sperm at 15 min, 2 h and 4 h (P<0.05), and so did butorphanol at 2 x 10(-3) and 0.05 mg/ml (P<0.05) and dezocine at 0.05 and 0.5 mg/ml (P<0.05), but neither showed any remarkable effect at 1 x 10(-5) mg/ml at the three time points (P>0.05). Pentazocine effected no significant difference at 3 x 10(-5) and 0. 05 mg/ml (P>0.05) but a gradual increase in the percentage of grade a + b sperm at 0.5 mg/ml at the three time points (P<0.05). Butorphanol totally inhibited sperm motility at 0.05 mg/ml at 15 min and at 2 x 10(-3) mg/ml at 2 h, and so did dezocine at 0.05 and 0.5 mg/ml, but such inhibitory effect was not observed with fentanil, alfentanil and sulfentanil at 0.05 mg/ml. As for the sperm motility decreasing effect at 0.05 mg/ml at 15 min, sufentanil, butorphanol and dezocine exhibited significant differences (P<0.05) while fentanyl displayed none from alfentanil (P>0.05).

CONCLUSIONGiven the same length of time of treatment, butorphanol and dezocine totally inhibit sperm motility at a high concentration, but make no significant change at a low concentration. While fentanyl, alfentanil and sufentanil can significantly decrease sperm motility at the same low concentration, and partially inhibit it at all concentrations. On the contrary, a high concentration of pentazocine can promote human sperm motility.