Comparison of anileridine and pethidine in patients with pain following upper abdominal surgery.

The analgesic potency of anileridine compared with pethidine was found to be 4:1 by measuring the effect on withdrawal movements resulting from pinching of the skin or surgery during N2O + O2 anaesthesia. The potency ratio was examined postoperatively as well. Sixty patients who had undergone upper abdominal surgery with standard anaesthesia were studied in a double-blind, between-patient two dose comparison. Each patient and an observer graded the degree of pain relief. Here again, anileridine proved 4 times as potent as pethidine. With higher doses the response to anileridine was of shorter duration than was the response to pethidine. Respiratory depression was very similar after equianalgesic doses. Blood pressure and pulse rate remained stable. The total incidence of side effects was higher after pethidine.