Circulatory collapse and obtundation occurred in a 37-year-old woman following an iatrogenic overdose of labetalol. Conventional therapy with glucagon and alpha-adrenergic receptor-stimulating agents was ineffective in raising the patient's cardiac output or improving her mental status despite increasing the arterial pressure. The administration of amrinone was temporally associated with significant increases in the cardiac output accompanied by improved mental status. This case suggests that amrinone may be effective adjunctive therapy for beta-adrenergic receptor blocker overdoses by reversing their negative inotropic effects.