Exenatide Injection and Warfarin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Warfarin
Exenatide Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of bleeding and an increase in INR
Interaction Deep Dive
There have been postmarketing reports for exenatide of increased INR with concomitant use of warfarin, sometimes associated with bleeding. In a pharmacokinetic study, administration of warfarin 35 minutes after repeated doses of exenatide delayed warfarin Tmax by approximately 2 hours, however no clinically relevant differences in Cmax, AUC or INR occurred1. In an open-label study, concurrent administration of exenatide and warfarin in healthy male patients did not lead to a clinically significant effect on warfarin pharmacokinetics or pharmacodynamics 3. Additionally in a small retrospective cohort study of patients receiving warfarin, the addition of a GLP-1 receptor agonist (GLP1-RA; including exenatide) did not significantly alter the time in therapeutic INR range during the 90 days after compared with the 90 days before GLP1-RA initiation 2. In patients treated with warfarin, monitor the prothrombin time (PT) more frequently after initiation or alteration of exenatide therapy. Once a stable PT has been documented, PT can be monitored at the interval recommended for patients treated with warfarin 1.
Why it happens (mechanism)
Delayed gastric emptying by exenatide resulting in increased warfarin absorption
Literature reports
3 reports — tap to read
a) In a small retrospective cohort study of patients receiving warfarin (N=28), the addition of a GLP-1 receptor agonist (GLP1-RA) did not significantly alter time in therapeutic INR range (TTR) during the 90 days after compared with the 90 days before GLP1-RA initiation. Patients were excluded if either medication was discontinued within 90 days of GLP1-RA initiation or fewer than 4 INR measurements were available within 90 days before and after GLP1-RA initiation. Participants were a mean of 59.4 years, 46% were male, and most were receiving warfarin for mechanical valves (n=9), followed by atrial fibrillation/flutter (n=7), or VTE (n=7); 5 patients were receiving warfarin for other indications. At baseline, 79% (n=22) had a diagnosis of diabetes. Semaglutide was the most commonly prescribed GLP1-RA (n=10), followed by exenatide (n=8), dulaglutide (n=5), liraglutide (n=4), and tirzepatide (n=1). The average TTR was 59% and 60% during the 90 days before and after GLP1-RA initiation, respectively, and the percentage of in-range INR was 56.6% and 51.9% for the pre- and post-initiation groups, respectively. No patients experienced bleeding after initiating a GLP1-RA. In a subgroup of patients with baseline TTR of 80% or more, TTR decreased to 70% post-GLP1-RA initiation 2.
b) In an open-label, 2-period, fixed-sequence study, coadministration of warfarin and exenatide did not have a clinically significant effect on warfarin pharmacokinetics or pharmacodynamics. Healthy, male subjects (n=25) received an oral 25-mg warfarin dose in period 1. In period 2, which commenced 1 week later, exenatide was administered subcutaneously for 4 days (5 mcg twice daily for 2 days, then 10 mcg twice daily for 2 days). On the fourth day, a second 25-mg warfarin dose was given orally within 35 minutes of the exenatide dose. Exenatide 10 mcg twice-daily dosing was continued for another 5 days. Mean plasma concentration time profiles were not significantly altered for both the R- and S-enantiomers of warfarin. The least squares (LS) geometric mean ratios (warfarin plus exenatide/warfarin in all cases) of AUC were 1.11 (90% confidence interval (CI), 1.06 to 1.17) and 1.06 (90% CI, 1.01 to 1.11) for R- and S-warfarin, respectively. The LS geometric mean ratios of Cmax were 1.05 (90% CI, 1 to 1.09) and 0.97 (90% CI, 0.93 to 1.01) for R- and S-warfarin, respectively. However, warfarin Tmax was delayed, with median increases of 1 hour and 2 hours for R- and S-warfarin, respectively. The maximal INR values were similar during both periods and the LS geometric mean ratio was 0.94 (90% CI, 0.93 to 0.96). No abnormal bleeding episodes occurred during the study. Although this interaction was not believed to be metabolism-related, the exact mechanism is unknown 3.
c) There have been postmarketing reports for exenatide of increased INR with concomitant use of warfarin, sometimes associated with bleeding. Administration of warfarin (25 mg) 35 minutes after repeated doses of exenatide (5 mcg twice daily on Days 1 and 2 and 10 mcg twice daily on Days 3 through 9) in healthy volunteers delayed warfarin Tmax by approximately 2 hours. No clinically relevant effects on Cmax or AUC of S- and R-enantiomers of warfarin were observed. Exenatide did not significantly alter the pharmacodynamic properties (eg, INR) of warfarin 1.
Common questions
Can I take Exenatide Injection and Warfarin together?
An increased risk of bleeding and an increase in INR Always confirm with your pharmacist or prescriber before making any change.
How serious is the Exenatide Injection and Warfarin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Exenatide Injection or Warfarin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (3)
- Product Information: BYETTA(R) subcutaneous injection, exenatide subcutaneous injection. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2025. DailyMed
- Anjum P, Akbashev M, Utz A, et al: Warfarin and GLP-1 receptor agonist interaction effects on time in therapeutic range. Blood 2024; 144(Suppl 1):5579. DOI
- Soon D, Kothare PA, Linnebjerg H, et al: Effect of exenatide on the pharmacokinetics and pharmacodynamics of warfarin in healthy Asian men. J Clin Pharmacol 2006; 46(10):1179-1187. PubMed
Keep reading about Warfarin
Keep reading about Exenatide Injection
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