Women experience more pain and require more morphine than men to achieve a similar degree of analgesia.

Unlabelled: Sex differences in pain perception and in response to opioids have been described, but the findings are inconsistent. We sought to determine the effect of sex on pain perception, morphine consumption, and morphine analgesia after surgery. We designed a prospective cohort study and included 423 women and 277 men who emerged from general anesthesia after surgical procedures and who reported pain intensity of >or=5 on the 0-10 numeric rating scale (NRS). We administered 2.5 mg of morphine IV every 10 min until the pain intensity was
Implications: The effect of sex on opioid response is not clear. To determine the effect of sex on morphine consumption and morphine analgesia, we designed a cohort study. We found that women had more intense pain and required 30% more morphine to achieve a similar degree of analgesia compared with men.