Interaction reference

GLP-1 receptor agonists with Warfarin

Warfarin has a narrow therapeutic window. Slowed gastric emptying from GLP-1s can shift warfarin absorption and INR.

Check INR more frequently for the first 6-8 weeks on a GLP-1.

Also known as: Coumadin, Jantoven

Per-GLP-1 breakdown

Wegovysemaglutide 2.4 mg
Moderate
Mechanism: GLP-1 delays gastric emptying, which can alter warfarin absorption. Reported INR shifts in both directions; no single predictable change.
What to do: INR check at 1, 2, 4, and 8 weeks after starting any GLP-1. Adjust warfarin dose only after a confirmed sustained shift. Once on GLP-1 maintenance for 3 months, INR stabilizes for most patients.
Zepboundtirzepatide
Moderate
Mechanism: GLP-1 delays gastric emptying, which can alter warfarin absorption. Reported INR shifts in both directions; no single predictable change.
What to do: INR check at 1, 2, 4, and 8 weeks after starting any GLP-1. Adjust warfarin dose only after a confirmed sustained shift. Once on GLP-1 maintenance for 3 months, INR stabilizes for most patients.
Ozempicsemaglutide
Moderate
Mechanism: GLP-1 delays gastric emptying, which can alter warfarin absorption. Reported INR shifts in both directions; no single predictable change.
What to do: INR check at 1, 2, 4, and 8 weeks after starting any GLP-1. Adjust warfarin dose only after a confirmed sustained shift. Once on GLP-1 maintenance for 3 months, INR stabilizes for most patients.
Mounjarotirzepatide
Moderate
Mechanism: GLP-1 delays gastric emptying, which can alter warfarin absorption. Reported INR shifts in both directions; no single predictable change.
What to do: INR check at 1, 2, 4, and 8 weeks after starting any GLP-1. Adjust warfarin dose only after a confirmed sustained shift. Once on GLP-1 maintenance for 3 months, INR stabilizes for most patients.
Foundayoorforglipron
Moderate
Mechanism: GLP-1 delays gastric emptying, which can alter warfarin absorption. Reported INR shifts in both directions; no single predictable change.
What to do: INR check at 1, 2, 4, and 8 weeks after starting any GLP-1. Adjust warfarin dose only after a confirmed sustained shift. Once on GLP-1 maintenance for 3 months, INR stabilizes for most patients.

Sources

GLP-1 receptor agonists and warfarin INR — Annals of Pharmacotherapy

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