Sustained-release diltiazem for stable angina pectoris
Diltiazem has been shown to be effective in the treatment of exertional angina pectoris. The recommended dose interval is six to eight hours, with a maximal daily dosage of 360 mg. Klinke and colleagues studied the safety and efficacy of sustained-release diltiazem with a twice-daily regimen.
A total of 80 patients with chronic stable angina were enrolled in the double-blind study. Eight patients were excluded for violating the study protocol, and seven withdrew prior to completion of the study. Before study entry, patients reported a mean of five episodes of angina per week. Seventeen of the patients had a history of myocardial infarction, and 12 had undergone coronary bypass surgery.
Coronary arteriography had been performed in 44 patients, revealing three-vessel disease in 18, two-vessel disease in 15 and one-vessel involvement in 11. None of the patients had congestive heart failure or valvular disease. Ten patients had controlled hypertension. All antianginal drugs (except sublingual nitroglycerin) and all cardiovascular drugs that interfere with the interpretation of ST-segment changes were discontinued before the pre-study exercise test and were withheld for the duration of the study.
Placebo or sustained-release diltiazem in a daily dosage of 240 mg or 360 mg was administered for consecutive seven-day periods. Each patient participated in each group in a random fashion. The overall mean compliance rate was 98.3 percent. Anginal episodes and nitroglycerin consumption were recorded by the patients in a diary. Exercise treadmill tests were performed in a standardized manner using the Bruce protocol. Patients refrained f rom smoking, eating or using sublingual nitroglycerin in the two hours preceding exercise.
Diltiazem reduced the number of episodes of spontaneous angina and increased exercise duration and time to occurrence of 1-mm ST-segment depression. No differences were noted between the two drug doses. Only one patient terminated the study because of adverse drug effects; severe adverse effects occurred during one placebo period and one low-dose period.
The authors believe that sustained-release diltiazem, 120 mg or 180 mg twice daily, is a safe and effective treatment in patients with stable exertional angina. (American Journal of Cardiology, December 1, 1989, vol. 64, p. 1249.)
COPYRIGHT 1990 American Academy of Family Physicians
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