[The nifedipine withdrawal syndrome in patients with stable stenocardia of effort].

The effect of abrupt discontinuation of nifedipine (N) on exercise tolerance and myocardial ischemia was studied in 7 patients with stable angina pectoris of effort (AP). N was administered in a dose of 20 mg 4 times a day for 34 days. Exercise treadmill tests were performed before N therapy in placebo treatment, on N treatment day 1, 28, on the first day after abrupt N discontinuation and 8 days after the latter. Upon acute and regular administration N produced a significant improvement in exercise tolerance before the onset of AP, development of moderate AP and up to 1 mm depression of ST-segment. Abrupt N discontinuation resulted in substantial deterioration in exercise performance pronounced more definitely on hour 21 and 24 after the last dose intake. A substantial increase in the sum of ST-segment depression at the onset of AP and at the development of AP of moderate severity occurred on the first day of N withdrawal. 8 days after N cessation all the exercise parameters returned to the baseline levels. We conclude that abrupt cessation of regular N therapy may cause a withdrawal syndrome which manifested with a decrease in the exercise tolerance and an increase in exercise-induced myocardial ischemia.