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Podcast for Healthcare Professionals:Ongoing Safety Review of Invirase and Possible Association with Abnormal Heart Rhythms

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Welcome, I'm Chris Jones, a pharmacist in the Division of Drug Information and today I am going to update you about an ongoing safety review of Invirase and possible association with abnormal heart rhythms.

The U.S. Food and Drug Administration (FDA) is reviewing data about a potentially serious effect on the heart from the use of Invirase (saquinavir) in combination with Norvir (ritonavir).

While FDA's review is ongoing,, the preliminary data suggests that the two drugs may prolong the QT or PR interval which may lead to torsade de pointes or heart block.

Invirase and Norvir are antiviral medications given together to treat HIV infection. Norvir is given at a low dose with Invirase in order to increase the level of Invirase in the body. This is a process known as "boosting."

The study data were submitted by Roche, the manufacturer of Invirase, based on FDA's request that all manufacturers of protease inhibitors, including Invirase, conduct a thorough QT study to evaluate the effect these drugs have on the QT and PR intervals.

The preliminary data show that when Invirase boosted with Norvir (1000mg/100mg) was given to healthy patients, ages 18 to 55 years, there was a dose-dependent prolongation of the QT and PR intervals.

The magnitude of the effect and clinical implications of QT and PR interval prolongation are still being reviewed by FDA. However, these finding suggests that some patients using Invirase boosted with Norvir may be at an increased risk for developing abnormal heart rhythms.

In particular, this risk may be increased in patients using other medications known to cause QT interval prolongation such as Class IA and Class III antiarrhythmic drugs or in patients with a history of QT interval prolongation.

FDA recommends that healthcare professionals:

  • Not use Invirase in patients with a history of QT interval prolongation, preexisting conduction system disease, ischemic heart disease, cardiomyopathy, or underlying structural heart disease.
  • Not use Invirase in patients who are currently using Class IA (such as quinidine) or Class III (such as amiodarone) antiarrhythmic drugs or other drugs that may prolong the QT or PR interval.
  • Report any adverse events associated with the use of Invirase to FDA's MedWatch program.

Thank you for listening. The FDA is committed to keeping healthcare professionals informed of the latest safety information. If you have any additional questions about this safety communication, you may reach the Division of Drug Information at the following email address: druginfo@fda.hhs.gov.


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