Effect of the addition of propranolol to therapy with nifedipine for unstable angina pectoris: a randomized, double-blind, placebo-controlled trial

Abstract

The value of the addition of beta-blockers to coronary vasodilator therapy in the treatment of patients with unstable angina at rest is controversial. We conducted a double-blind, randomized, placebo-controlled 4 week trial of propranolol in 81 patients with unstable angina, 39 of whom were assigned to placebo and 42 of whom received propranolol in a dose of at least 160 mg daily. All patients were also treated with coronary vasodilators, including 80 mg nifedipine daily and long-acting nitrates. The incidences of cardiac death, myocardial infarction, and requirement for bypass surgery or coronary angioplasty did not differ between the two groups (propranolol = 16; placebo = 18). The propranolol group had a lower cumulative probability of experiencing recurrent resting angina than the placebo group (p = .013), and over the first 4 days of the trial the mean number of clinical episodes of angina (propranolol 0.9 +/- 0.2, placebo 1.8 +/- 0.3, p = .036), duration of angina (propranolol 15.1 +/- 4.3 min, placebo 38.1 +/- 8.4, p = .014), and nitroglycerin requirement (propranolol 1.1 +/- 0.3 tablets, placebo 3.5 +/- 0.8, p = .003) were also fewer. Continuous electrocardiographic recording for ischemic ST segment changes revealed fewer daily ischemic episodes in the propranolol group (2.0 +/- 0.5) than in the placebo group (3.8 +/- 0.7, p = .03), and a shorter duration of ischemia (propranolol 43 +/- 10 min, placebo 104 +/- 28 min, p = .039). Thus propranolol, in patients with unstable angina, in the presence of nitrates and nifedipine is not detrimental and reduces the frequency and duration of symptomatic and silent ischemic episodes.