Canadian Journal of Anesthesia, Vol 38, 704-709, Copyright © 1991 by Canadian Anesthesiologists' Society

ARTICLES

A comparison of propranolol and diazepam for preoperative anxiolysis

JB Dyck and F Chung
Department of Anaesthesia, Toronto Western Division, Toronto Hospital, University of Toronto, Ontario, Canada.

The effectiveness of propranolol, a nonsedating anxiolytic premedication, was studied by monitoring preoperative anxiety and postoperative recovery of cognitive function in 92 healthy ASA physical status I females aged 15-42 yr undergoing outpatient dilatation and curettage (D&C) for therapeutic abortion. In a randomized double-blind design, patients received one of the following oral medications 1-1.5 hr preoperatively: (1) diazepam 10 mg (n = 31); (2) propranolol 80 mg (n = 31); (3) placebo (n = 30). Anxiety throughout the hospital stay was monitored using the State-Trait Anxiety Inventory (STAI). Postoperative cognitive recovery was assessed using the digit span and Trieger tests. STAI anxiety levels were recorded on admission to hospital, immediately before entering the operating room, and two hours postoperatively. There was no difference among the anxiolytic properties of the three medications and all three patient groups showed a significant decrease in anxiety levels after administration of the medication. Tests of cognitive function after anaesthesia showed the fastest return to baseline status in patients receiving propranolol, possibly because beta adrenergic blockade blunted the autonomic signs of light anaesthesia and less anaesthetic was administered. None of the study premedications was demonstrated to have an anxiolytic advantage, but propranolol did offer a faster return of cognitive function in the postoperative period.