Drugs that May Interact with Protease Inhibitors via CYP3A4 Metabolism -- Table V
December 18, 1997
The following is a list of medications that may potentially interact with ritonavir therapy via cytochrome P450, specifically CYP3A4 isoenzyme metabolism. Clinical trials measuring the magnitude of these potential interactions have not been conducted. Additionally both saquinavir and indinavir are metabolized via CYP3A4. The extent of these interactions is unknown at this time. Therefore, it may be appropriate to use therapeutic drug concentration monitoring, and/or increased monitoring of therapeutic and adverse effects when concomitantly administering any of the following medications with protease inhibitors, especially for agents with narrow therapeutic margins. Dosage reductions may be required for those medications that are extensively metabolized by CYP3A4.
Please refer to Norvir product labeling information for further details regarding other potential drug interactions via CYP2D6, CYP2C9/19, glucuronidation and other pathways.
Reference: Norvir Prescribing Information (March 1, 1996)
Effects of Protease Inhibitors and Other Commonly Used Medications as Determined by Drug Interaction Studies -- Table IV
This article was provided by U.S. Food and Drug Administration. It is a part of the publication Protease Inhibitors Backgrounder. Visit the FDA's website to find out more about their activities and publications.