Combined pre‐incisional oral dextromethorphan and epidural lidocaine for postoperative pain reduction and morphine sparing: a randomised double‐blind study on day‐surgery patients

The reduction in acute pain perception following dextromethorphan has previously been investigated in patients undergoing general anaesthesia. This random and double‐blind study examined the effects of pre‐incisional oral dextromethorphan on postoperative pain and intravenous patient‐controlled morphine demand in 60 day‐surgery patients undergoing lower body surgery under lidocaine (1.6%−16 ml) epidural anaesthesia after receiving placebo, 60 or 90 mg dextromethorphan, 90 min pre‐operatively. Postoperative pain was scored on a visual analogue scale from 1 to 10. In‐hospital observation continued for 6 h and for 3 days at home; diclofenac was available throughout. Dextromethorphan‐treated patients reported significantly (p