Haemodynamic effects of verapamil administration after large doses of fentanyl in man

Thirteen patients with good left ventricular function undergoing coronary artery revascularization were studied to determine the cardiovascular effects of verapamil, 75-150 micrograms X kg-1, after a large dose (100 micrograms X kg-1) of fentanyl, with pancuronium for muscle relaxation. The patients were continued on their usual cardiovascular medications until the time of surgery, which included nitrates, beta adrenergic blockers, and nifedipine. Anaesthesia with fentanyl was associated with decreases in mean arterial blood pressure, systemic vascular resistance, left ventricular stroke work index, and circulating catecholamine levels. Mean values were not further changed by verapamil, but individual patients had additional modest decreases in blood pressure and systemic vascular resistance. Cardiac index, however, was well maintained. Plasma catecholamines remained depressed after verapamil under the study condition. Thus, in patients with good left ventricular function, clinically relevant doses of verapamil were well tolerated even in the presence of an anaesthetic that included large doses of fentanyl, with suppression of circulating catecholamine levels.