Influence of timing of morphine administration on postoperative pain and analgesic consumption.

Abstract

We have investigated if a pre-emptive dose of morphine, given 30 min before skin incision, influenced postoperative pain and morphine consumption after hysterectomy. In a prospective, randomized, double-blind, placebo-controlled clinical study, patients received morphine 0.3 mg kg-1 at induction of anaesthesia or 30 min later at skin incision. The primary endpoint was defined as 24-h morphine consumption via patient-controlled analgesia. We could not demonstrate any difference between the two groups in morphine consumption or pain scores, and we conclude that there was no evidence of pre-emptive analgesia in this study.