| Abstract: | The beneficial effect of calcium antagonists in the treatment of vasospastic angina is now well recognized. Although withdrawal symptoms have been reported following abrupt cessation of therapy with some cardiovascular drugs, there is no detailed report on similar complications of the cessation of therapy with calcium antagonists. In a 4-month period eight patients with well documented and well controlled vasospastic angina experienced a marked increase in the frequency and duration of anginal episodes at rest following the involuntary cessation of treatment with nifedipine, 10 to 20 mg four times a day. The increase began within 2 to 5 days after the cessation of treatment. Substitute therapy with isosorbide dinitrate, 30 mg, and verapamil, 80 to 120 mg, each four times a day, was effective in all cases. Although the mechanism responsible for this rebound phenomenon is not known, awareness of its existence is essential considering the widespread use of calcium antagonists. |
