Noncardiac surgery in patients receiving propranolol. Case reports and recommended approach.

Signs consistent with the propranolol withdrawal rebound syndrome may occur when propranolol hydrochloride administration is temporarily discontinued because of major noncardiac surgical procedures. The time course of the appearance of these signs indicates that the risk of the propranolol withdrawal rebound syndrome peaks about four to seven days after drug discontinuation. Continuation of propranolol up to the time of surgery appears safe from an anesthetic standpoint and may also help to postpone the risk of the withdrawal rebound syndrome until after oral propranolol therapy can be reinstituted.