EFM -- European researchers found that the anti-retroviral Ziagen (also known as Abacavir), included as part of many anti-AIDS regimens worldwide, almost doubled patients’ risks of heart problems. Also, didanosine (Videx) increased the heart attack risk by about 50 percent. GlaxoSmithKline PLC makes Ziagen, while Bristol-Meyers Squibb makes Videx.