A drug used for more than 40 years to treat gout can also relieve angina, say researchers.
Compared to other angina drugs, allopurinol is inexpensive and appears to work by reducing the energy needs of the heart, reports the Lancet.
The severe chest pain of angina occurs when the heart muscle is deprived of blood, and therefore oxygen.
In the Dundee University study, 65 angina patients took part. And after analyses, boffins found that those on allopurinol could exercise for longer without getting chest pain.
Professor Allan Struthers and his team told the Lancet journal: "On the basis of our results, allopurinol is a useful anti-ischaemic treatment option in patients with angina that has the advantage of being inexpensive, well tolerated and safe in the long term.
"The precise place of allopurinol in the management of angina pectoris now needs to be explored further, but this drug might be especially appealing for use in developing countries where coronary artery disease is rapidly increasing in frequency and where access to expensive drugs or invasive treatments (angioplasty and bypass surgery) is often restricted."