The findings, published in the journal Lancet, have prompted a U.S. Food and Drug Administration review of the anti-viral medication, the San Francisco Chronicle said Wednesday.

The University of Copenhagen study of more than 33,000 HIV-infected patients in North America, Europe and Australia showed that patients taking abacavir had a 90 percent greater chance of developing a heart attack. The risk of heart attack increased by 49 percent in patients taking the drug didanosine.

The FDA said an effort is under way to evaluate the overall risks and benefits of abacavir and didanosine.

"Until this evaluation is complete, healthcare providers should evaluate the potential risks and benefits of each HIV-1 anti-retroviral drug their patients are taking, including abacavir and didanosine," the agency said in an online statement.

A federal panel this year recommended that abacavir, combined with the anti-viral 3TC and sold as Epzicom, be considered a preferred choice for patients taking AIDS drugs for the first time, the newspaper said.