Warfarin (Coumadin 5 mg) and Efavirenz: interaction and safety
This source-based reference is not a personal treatment recommendation. The relevance and management of an interaction depend on the exact products, route, dose and clinical situation.
Interaction mechanism
Efavirenz can increase or decrease warfarin exposure.
Clinical significance and safety
Warfarin response can change in either direction. INR monitoring should be reviewed when efavirenz is started or stopped, and any anticoagulant change should be made by the prescriber.
Using this information
This is a source-based reference record, not a recommendation to combine, stop or change medicines. A missing interaction record does not establish safe use. A qualified healthcare professional should consider the exact products, doses, other medicines and individual health circumstances.