Rebound vasospasm after coronary revascularization in association with calcium antagonist withdrawal.

Four patients experienced life-threatening coronary vasospasm following discontinuation of calcium channel blocking medication at the time of coronary revascularization. The last dose of the calcium blocker in each instance was administered between 8 and 18 hours before operation. Two of the patients were receiving diltiazem (60 mg four times a day) and 2, nifedipine (20 mg four times a day).