Time course of antirecall effect of diazepam and lorazepam following oral administration.

The time course of antirecall effect and grades of sedation after the oral administration of diazepam and lorazepam were determined in 120 patients. Three standard doses of each drug were employed. Grades of sedation following oral diazepam were dose related, with a latency of 30-60 min and duration of 120-150 min. All three doses of lorazepam produced significantly more sedation with a similar latency (30-60 min) but longer duration (more than 240 min). Peak frequencies of the antirecall effects of diazepam 10, 15, and 20 mg were 5, 20, and 30 per cent, respectively. The duration was about two hours. Peak frequencies of the antirecall effect after lorazepam 2, 3, and 4 mg were 30, 45, and 72 per cent, respectively. Latency of peak action was about 60-90 min for all the doses, but the duration, especially with 3 and 4 mg doses, was long (4 h).