Patient‐controlled postoperative analgesia with alfentanil

A double-blind study comparing alfentanil and pethidine given intravenously by an adaptive, patient-controlled on-demand analgesic system is described. It was demonstrated that, despite its well-known rapid onset of effect, alfentanil took several hours to achieve good quality analgesia. Nevertheless, it had a much more predictable consumption pattern than pethidine. Alfentanil was associated with significantly less sedation during the postoperative period than pethidine, and was also associated with a significantly greater urine output during the 24-hour period of study. There was no evidence of tolerance or accumulation with either of the two drugs.