Combined HIV drug therapy may cause heart rhythm issues

ROCKVILLE, Md. Combining two HIV drugs made by Roche subsidiary Genentech and Abbott could cause abnormalities in patients’ heart rhythms, the Food and Drug Administration said Tuesday.

The FDA announced preliminary data suggesting that combining Roche’s Invirase (saquinavir) and Abbott’s Norvir (ritonavir) could prolong the heart’s QT and PR intervals. Prolongation of the QT interval can lead to a condition known as torsades de pointes, an abnormal heart rhythm, while a prolonged PR interval can lead to heart block, also an abnormal heart rhythm. Both conditions can cause lightheadedness, fainting or abnormal heart beats. In some cases, torsades de pointes can progress to ventricular fibrillation, a potentially fatal irregular heartbeat.

The FDA said review of the data was ongoing.