A topic in Clinical Evidence 1 summarizes the evidence on beta blockers for patients with unstable angina. Two RCTs were found. The first RCT (n=338) found that metoprolol vs nifedipine significantly reduced combined outcome of recurrent angina or myocardial infarction within 48 hours (28% vs 47%, RR 0.66, 95% CI 0.43 to 0.98). The second RCT (n=81) included patients with unstable angina on ´optimal´ doses of nitrates and nifedipine and found no significant difference between propranolol (least 160 mg daily) versus placebo (RR 0.83, 95% CI 0.44 to 1.30) in the incidence of cardiac death, myocardial infarction or need of CABG or PTCA at 30 days. People taking progranolol had a lower cumulative probability of experiencing recurrent rest angina over the first 4 days of the trial. The mean number of clinical episodes of angina, duration of angina, glyceryl trinitrate requirement, and ischaemic ST changes by continuous ECG monitoring was also lower.
Clinical evidence category: Unknown effectiveness.
Comment: The quality of evidence is downgraded by sparse data and indirectness of evidence (insufficient data on mortality).
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