Comparative efficacy of propranolol, chlordiazepoxide, and placebo in the treatment of anxiety: a double-blind trial

Abstract

The efficacy and safety of propranolol in the treatment of anxiety was compared with those of chlordiazepoxide and placebo in a 3-week, double-blind study of 212 patients. After a 1-week, single-blind placebo-washout period, patients were randomized to receive either propranolol (80, 160, or 320 mg/day), chlordiazepoxide (30, 45, or 75 mg/day), or placebo. Patients were evaluated by three physician-rated scales--Hamilton Rating Scale for Anxiety (HAM-A), Covi Anxiety Scale (CAS), and Clinical Global Impressions scale--and two patient-rated scales--Symptoms Checklist 90 and Profile of Mood States. Patients in all groups demonstrated significant improvement in their level of anxiety at all time points compared with their baseline level. At Week 1 propranolol and chlordiazepoxide patients were significantly better than placebo patients, as measured by the HAM-A and CAS. At Week 2 only propranolol was superior to placebo, based on HAM-A and CAS scores. Fifteen patients prematurely terminated because of adverse reactions (4 taking propranolol, 4 taking placebo, and 7 taking chlordiazepoxide). The incidence of side effects was similar for the two active drugs; fatigue, drowsiness, and change in libido were significantly more frequent with chlordiazepoxide and drowsiness and indigestion were more frequent with propranolol compared with placebo.