The Kinetic and Dynamic Characteristics of Benzodiazepines in the Treatment of Anxiety

Abstract

SummaryBenzodiazepines are assumed to cause drowsiness and sedation. Rating scales such as the Massachusetts General Hospital Sedation Scale and the Morning Evaluation of Drug Induced Sedation Scale allow testing of this hypothesis and assessment of the effects of benzodiazepines. We performed a five-week study of prazepam in 63 anxious outpatients. Plasma levels of desmethyldiazepam were assessed weekly. Placebo was given the first week, followed by active drug for three weeks, and placebo the final week. One group received prazepam 30 mg/h, the other received prazepam 10 mg three times per day. Drowsiness-sedation and anxiolytic efficacy were assessed at baseline and weekly. Plasma desmethyldiazepam levels were similar in both treatment groups. Efficacy was profound in both groups. Drowsiness-sedation measured high at baseline and decreased significantly (P=0.05) over the 3 weeks when active drug was administered. Sedation decreased by as much as 40%. Sleep was improved with prazepam, and this may have resulted in decreased drowsiness. We conclude that anxious outpatients have significant levels of drowsiness-sedation and that treatment with benzodiazepines reduces the occurrence of this symptom.