Warfarin with Exenatide Interaction Details
Brand Names Associated with Warfarin
- Coumadin®
- Jantoven®
- Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 07, 2023
Interaction Effect
An increase in INR
Interaction Summary
Concurrent administration of exenatide and warfarin in healthy males did not lead to a clinically significant effect on warfarin pharmacokinetics or pharmacodynamics in an open-label, 2-period, fixed-sequence study. However, during postmarketing surveillance, cases of increased INR, sometimes associated with bleeding episodes, have been reported with concurrent use. More frequent monitoring of prothrombin time or INR when initiating or changing exenatide therapy is recommended. Once stabilized, usual monitoring frequency may be resumed .
Severity
Moderate
Onset
Unspecified
Evidence
Probable
How To Manage Interaction
Although coadministration of exenatide and warfarin in healthy males did not significantly alter warfarin INR and had minimal effects on warfarin pharmacokinetics, cases of increased INR, sometimes associated with bleeding, have been reported with during postmarketing surveillance . More frequent monitoring of prothrombin time or INR when initiating or changing exenatide therapy is recommended. Once stabilized, usual monitoring frequency may be resumed .
Mechanism Of Interaction
Unknown
Literature Reports
A) 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 .
Warfarin Overview
-
Warfarin is used to prevent blood clots from forming or growing larger in your blood and blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have suffered a heart attack. Warfarin is also used to treat or prevent venous thrombosis (swelling and blood clot in a vein) and pulmonary embolism (a blood clot in the lung). Warfarin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.
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Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.