Combinations of ??-Blockers and Calcium Channel Blockers

Abstract

Many patients are treated for angina pectoris with a combination of a calcium channel blocker and a β-blocking agent. The safety and efficacy of such combination therapy are well-documented (1,2). When considering any modification of this drug regimen preoperatively, most anesthetists elect to continue all antianginal medications until the time of surgery. A recent editorial supports this view (3), and more important, the only prospective study published to date (4) provides a solid basis for this practice. However, adverse effects have been reported with the use of such combinations, most commonly when verapamil is combined with a β-blocker. Left ventricular dysfunction, bradyarrhythmias, complete heart block, hypotension, and death have all been described (5–7). Furthermore, we now are seeing patients treated with a three-drug regimen consisting of a β-blocker plus two calcium channel blockers (nifedipine plus diltiazem or verapamil). The challenge is to anticipate which patients and which drug combinations present the greatest risk for perioperative hemodynamic problems. We report a patient with coronary artery disease, chronically treated with nifedipine, diltiazem, and nadolol, who developed malignant bradyarrhythmias and hypotension during anesthetic induction. Hemodynamic restoration required aggressive pharmacologic treatment, including an isoproterenol infusion. The severe conduction problems seen in this patient and the pharmacologic treatment required may have contributed to the patient's early postoperative demise.