Alpha-adrenergic blockade for variant angina: a long-term, double-blind, randomized trial.

Publisher Website
Google Scholar
Abstract
Recent reports have shown that .beta.-adrenergic blockade may exacerbate variant angina. On theoretical grounds, .alpha.-adrenergic blockade may be beneficial in these patients. To test this hypothesis, the efficacy of prazosin, an .alpha.-adrenergic blocking agent, was assessed in 6 men, mean age 49 yr, with variant angina. Prazosin, 14.0 .+-. 2.4 mg/day (mean .+-. SD) in 3 equal doses, was compared with placebo in a double-blind, randomized, double-crossover trial lasting 4.5 mo.: 2 wk of open-label prazosin followed by four 1 mo. periods of blinded alternating therrapy. No other vasoactive medications were administered during the study. Prazosin reduced sitting systolic arterial pressure from 145 .+-. 18 to 127 .+-. 16 mmHg (P = 0.02), but exerted no effect on diastolic arterial pressure or heart rate. Prazosin did not change the weekly number of episodes of chest pain (2.5 .+-. 2.3 with placebo vs. 3.1 .+-. 3.0 with prazosin, NS [not significant]), nitroglycerin tablets used (3.9 .+-. 3.7 with placebo vs. 4.6 .+-. 4.2 with prazosin, NS), or transient ST-segment deviations (by calibrated 2-channel Holter monitoring for 24 h/wk throughout the study) (6.5 .+-. 10.1 with placebo vs. 11.8 .+-. 17.4 with prazosin, NS). During prazosin therapy, 3 patients had orthostatic dizziness and 1 patient had a headache. Thus, in a long-term, randomized, double-blind trial, prazosin exerted no obvious beneficial effect in patients with variant angina.