Allopurinol, a drug that has been used to treat gout for more than 40 years may have value as a new treatment for angina, according to researchers at the University of Dundee in the United Kingdom. The study, published in Online First and slated for an upcoming issue of the journal The Lancet, shows that the drug prolongs exercise capacity in chronic stable angina, and could be a cheap alternative to conventional treatments.
 

Angina causes severe chest pain because of restricted blood flow caused by obstructions or spasms of the coronary arteries that restricts oxygen flowing to heart muscle. Coronary artery disease, the main cause of angina, is due to a build-up of material in the arteries that can cause such obstructions. Chronic stable angina substantially reduces quality of life, with one in three patients having an angina attack at least once a week. About 5 percent of adult males in the United Kingdom suffer from the condition.

 

The researchers say experimental evidence on allopurinol suggests that it inhibits the enzyme xanthine oxidase, which in turn reduces the energy used by the heart in each beat. If such an effect also occurs in man, the researchers say, this class of inhibitors could become a new treatment for ischemia in patients with angina pectoris, since it would allow more oxygen and energy to reach heart tissue suffering inadequate blood supply in angina patients.

 

In the study, the researchers assessed whether high-dose allopurinol prolongs exercise capability in patients with chronic stable angina. A total of 65 patients (aged 18-85 years) with clinically diagnosed coronary artery disease, a positive exercise tolerance test, and stable chronic angina pectoris (for at least 2 months) were recruited into a double-blind, randomized, placebo-controlled, crossover study in a hospital and two infirmaries in the United Kingdom. The primary endpoint was the time to ST depression, an indication of ischemia in an electrocardiogram. The secondary endpoints were total exercise time and time to chest pain.

 

The study found allopurinol increased the median time to ST depression. Allopurinol also increased median total exercise time and increased the time to chest pain. No adverse effects of treatment were reported. The researchers note the drug is inexpensive compared to anti-anginal drugs used today and has a favorable safety record during its 40 years of use as a gout treatment. Compared to nitrates and beta blockers it has the advantage of not reducing blood pressure or heart rate, or cause side-effects, such as headaches and tiredness, that are common with these other drugs.

 

The researchers say additional study is now needed on how to best use allopurinol in the management of angina, but that the drug might be especially attractive for use in developing countries where coronary artery disease is rapidly increasing in frequency and where access to expensive drugs or invasive treatments is often restricted.