Anterograde amnesic effects of pethidine, hyoscine and diazepam in adults

1. The intravenous administration of 5 and 10 mg of diazepam caused anterograde amnesia in 50 and 90% of adults, the peak effect occurring in 2-3 min and action persisting for 20-30 minutes.2. Hyoscine (0.4 and 0.6 mg) caused amnesia in 35 and 50% of patients with peak effect not occurring until 50-80 min after injection and action persisting for at least 120 minutes.3. With neither drug was there any relationship between the incidence of amnesia and the degree of drowsiness.4. Amnesia was not observed after saline or after 50 mg pethidine.5. On questioning 6 h after a short operation many patients had no memory of an object which they clearly recognized and described 1 h after surgery.