LIFE-THREATENING INTERACTION OF MIBEFRADIL AND BETA-BLOCKERS WITH DIHYDROPYRIDINE CALCIUM-CHANNEL BLOCKERS

Mibefradil is a T-type and L-type calcium channel blocker (CCB) releas ed in the United States in 1997 for management of hypertension and chr onic stable angina. Postmarketing surveillance revealed a potential se rious interaction between mibefradil and beta-blockers, digoxin, verap amil, and diltiazem, especially in elderly patients. The manufacturer voluntarily withdrew mibefradil on June 8, 1998. We describe 4 cases o f cardiogenic shock in patients taking mibefradil and beta-blockers wh o began taking dihydropyridine CCBs. One case resulted in death; the o ther 3 survived episodes of cardiogenic shock with intensive support o f heart rate and blood pressure. Physicians who are preparing to switc h patients' medications from mibefradil to other antihypertensive agen ts should be aware of these potentially life-threatening drug-drug int eractions.