• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services


  • Print
  • Share
  • E-mail

Invirase (saquinavir mesylate) tablets

Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) – October 2010

Summary View



  • QT interval prolongation and torsades de pointes have been reported rarely with Invirase/ritonavir use. Do not use in patients with congenital long QT syndrome, those with refractory hypokalemia or hypomagnesemia,and in combination with drugs that both increase saquinavir plasma concentrations and prolong the QT interval


PR Interval Prolongation
  • Saquinavir/ritonavir prolongs the PR interval in a dose-dependent fashion. Cases of second or third degree atrioventricular block have been reported rarely. Patients with underlying structural heart disease, pre-existing conduction system abnormalities, cardiomyopathies and ischemic heart disease may...
QT Interval Prolongation
  • The impact on the PR interval of co-administration of saquinavir/ritonavir with other drugs that prolong the PR interval (including calcium channel blockers, beta-adrenergic blockers, digoxin…
  • Patients initiating therapy with ritonavir-boosted Invirase: An ECG should be performed prior to initiation of treatment. Patients with a QT interval > 450 msec…
  • Patients requiring treatment with medications with the potential to increase the QT interval and concomitant ritonavir-boosted Invirase: Such combinations should only be used where no alternative therapy is available and the potential…


Established and Other Potentially Significant Drug Interactions
  • Based on the finding of dose-dependent prolongations of QT and PR intervals in healthy volunteers receiving Invirase/ritonavir, additive effects on QT and/or PR interval prolongation may occur with...

Table 3

  • rifabutin: addition of a statement recommending dose reduction of the rifabutin when used in combination with Invirase/ritonavir