FDA is reviewing clinical trial data suggesting that using Invirase (saquinavir) in combination with Norvir (ritonavir) may increase the risk of cardiac arrhythmias. Invirase and Norvir are protease inhibitors used in combination to treat HIV infection.
The study was conducted by Roche, the manufacturer of Invirase, in response to FDA’s request that all manufacturers of protease inhibitors evaluate the effect of these drugs on QT and PR intervals. The study showed that healthy volunteers given Invirase boosted with Norvir experienced a dose-dependent prolongation of the QT and PR intervals.
FDA is evaluating the data and will provide an update when the review is done. In the meantime, FDA recommends that healthcare professionals not treat certain patients with Invirase. These include those already taking Class 1A or Class III antiarrhythmic drugs, or other drugs that many prolong the QT or PR intervals. Also, Invirase should not be used in patients with a history of prolonged QT intervals, preexisting conduction system disease, ischemic heart disease, cardiomyopathy, or underlying structural heart disease.