FDA Advises Patients and Care Providers on Drug Combination Safety Considerations
The U.S. Food and Drug Administration (FDA) is committed to keeping the public updated on advances and shifts in treatment options and methods. The FDA is reviewing data that suggest use of the HIV drug Invirase (saquinavir) in combination with Norvir (ritonavir) may have a potentially serious effect on a patient’s heart.
The data, drawn from clinical trials, indicate that the two drugs taken together may affect the normal electrical activity of the heart.
Invirase and Norvir are antiviral medications used to treat HIV infection. Norvir is given at a low dose with Invirase in order to increase the level of Invirase in the body, a process known as “boosting.”
The abnormal electrical activity of the heart possibly associated with these drugs, called prolonged QT or PR intervals, can be seen on an electrocardiogram. A prolonged QT interval can increase the risk for abnormal heart rhythms, including a serious abnormal rhythm called torsades de pointes.
A prolonged PR interval can cause the electrical signal responsible for generating a heart beat to slow or even stop. This is called heart block and it can affect how well the heart pumps blood.
The FDA’s analysis of these data is ongoing. However, health care professionals and their patients should be aware of this potential risk for abnormal electrical activity of the heart.
Invirase and Norvir should not be used in patients already taking medications known to cause QT interval prolongation. These medications include Class IA antiarrhythmic drugs such as quinidine and Class III antiarrhythmics such as amiodarone. The Invirase and Norvir combination also should not be used in patients with a history of QT interval prolongation.
The FDA safety announcement says that patients should not stop taking their prescribed antiviral medications. Those concerned about possible risks associated with using Invirase and Norvir should talk to their health care professional.
This communication is in keeping with FDA’s commitment to inform the public about its ongoing safety review of drugs. The agency will update the public as soon as this review is complete.
Here’s an overview of the FDA safety announcement for Patients
Those currently using Invirase should:
- Not stop taking Invirase without talking with their health care professional
- Discuss any questions or concerns they have about Invirase with their health care professional
- Review their cardiovascular medical history and current medications with their health care professional to determine if they should continue using Invirase
- Report any side effects with Invirase to FDA’s MedWatch program online at https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm or call 800-332-1088. You may fax the report to 800-332-0178.
Information for Health Care Professionals
The FDA recommends that health care professionals:
- Not use Invirase in patients with a history of QT interval prolongation, pre-existing 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 with the use of Invirase to FDA’s MedWatch program online at https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm or call 800-332-1088. You may fax the report to 800-332-0178.
Here’s the link to the Safety Announcement on the FDA Web site: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fda-drug-safety-communication-ongoing-safety-review-invirase-saquinavir-and-possible-association