Parenteral-verapamil-induced sustained hypotension.

The incidence of oral-verapamil-induced hypotension in the presence of concomitant beta-adrenergic blockade by the oral route is quite rare. The major contraindication to the use of intravenous verapamil is recent administration of intravenous beta-blocking agents (i.e., within the past two hours). We report a case of sustained hypotension after administration of parenteral verapamil. Vasopressors were required to support blood pressure for approximately five hours. The patient had been on oral propranolol for the past five years and had taken his last dose of propranolol approximately ten hours before the administration of parenteral verapamil for treatment of a supraventricular tachycardia documented by an electrocardiogram.