A large international HIV study announced some unexpected results in January: The antiviral meds abacavir (Ziagen, also in Epzicom and Trizivir) and didanosine (Videx) raised the risk of heart attack. In the study (Data Collection on Adverse Events of HIV Drugs or D:A:D), abacavir and didanosine lifted heart attack risk among participants by 90 and 49 percent, respectively.

The increase likely poses the most danger to those with other risk factors like smoking, diabetes or high blood pressure. For those whose initial risk level is small, the raise may prove insignificant. In D:A:D, the effect applied only to current users of the meds: When people switched the meds, the increase disappeared too.

For more info, search POZ.com for our special report: “Reckoning the Risk: Abacavir, Didanosine and Heart Disease Risk.”