In a small study, allopurinol improved exercise tolerance in patients with CAD.
Experimental evidence suggests that allopurinol lowers myocardial oxygen consumption. To assess whether this effect might benefit patients with cardiac ischemia, U.K. investigators randomized 60 patients with chronic stable exertion- induced angina, angiographically proven coronary artery disease, and positive exercise stress tests to add daily allopurinol (600 mg) or placebo to their baseline angina medications for 6 weeks; patients then crossed over to the opposite treatment for 6 weeks.
Exercise stress testing was performed after randomization and at the end of each treatment period. Compared with placebo recipients, allopurinol recipients exhibited significantly longer mean total exercise time (393 vs. 307 seconds), mean time to ST depression (298 vs 249 seconds), and mean time to symptoms (304 vs. 272 seconds). No adverse treatment effects were noted.
The anti-ischemic effect of allopurinol that was demonstrated in this study is comparable to that of other drugs such as amlodipine and nitrates, but its mechanism remains obscure. The authors speculate that allopurinol might reduce oxidative stress, thereby making more molecular oxygen available to ischemic myocardium and improving endothelial function. Although allopurinol generally is tolerated well, serious adverse effects occur occasionally. Thus, in future trials, researchers should compare allopurinol to other anti-anginal agents and include more patients and clinical outcomes.
Noman A et all. Effect of high-dose allopurinol on exercise in patients with chronic stable angina: A randomized, placebo controlled crossover trial.
Lancet 2010 Jun 19; 375:2161