A drug commonly used to fight AIDS appears to nearly double the risk of a heart attack, researchers said. In a study published online in The Lancet medical journal, European researchers said that the antiretroviral abacavir, included as part of many anti-AIDS regimens worldwide, almost doubled patients' chances of heart problems. The lesser-used drug didanosine also increased the heart attack risk by about 50 per cent. Abacavir, also known as Ziagen, is made by GlaxoSmithKline PLC. Didanosine, or Videx, is made by Bristol-Meyers Squibb.