Abstract
Effects of prazepam and diazepam on the latencies of the PPR were studied in 8 male, healthy volunteers. Drugs were administered orally in a cross-over design with a double-blind method and subsequently the PPR was recorded repeatedly. The self-assessments after dosing were checked. Diazepam 5 mg prolonged the P1 latency significantly as compared with placebo 2 hours after dosing. Prazepam 10 mg and 20mg prolonged the P1 latency depending on the doses. The degree of the prolongation of P1 latency after diazepam 5 mg administration was stronger than that after prazepam 20mg. Prazepam prolonged the P2 latency in a dose-depend-ent manner and showed the maximal prolongation 2 hours after medication. Compared with placebo, prazepam 20mg and diazepam 5mg prolonged the P2 latency significantly 2 and 3 hours after medication, while the prolongation of P2 latency after the former administration was more marked than that after the latter. From these results, it was suggested that prazepam had an anxiolytic action and its most effective time might be 2 or 3 hours after medication and the equipotent dose of prazepam to diazepam 5mg might be 15-20mg.
