Mesalamine with Warfarin Interaction Details
Brand Names Associated with Mesalamine
- 5-ASA
- Apriso®
- Asacol HD®
- Asacol®
- Delzicol®
- Lialda®
- Mesalamine
- mesalazine
- Pentasa®
Brand Names Associated with Warfarin
- Coumadin®
- Jantoven®
- Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 25, 2023
Interaction Effect
Decreased warfarin efficacy
Interaction Summary
The addition of mesalamine therapy to a stable regimen of warfarin resulted in a lack of a hypoprothrombinemic effect which caused a deep vein thrombosis in a 51-year-old female. Serum warfarin concentrations were not detectable. Although the mechanism is not known, possible causes include mesalamine inhibiting or preventing the absorption of warfarin.
Severity
Moderate
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Prothrombin time (PT) or international normalized ratio (INR) should be closely monitored in patients receiving warfarin and mesalamine therapy concurrently.
Mechanism Of Interaction
Unknown
Literature Reports
A) Warfarin 5 mg daily was being administered to a 51-year-old morbidly obese female with an international normalized ratio (INR) maintained between 2 and 3. Four weeks after she was prescribed mesalamine 800 mg three times daily, she presented with left leg pain and erythema of one day's duration. Lab values included prothrombin time (PT) of 11.3 seconds, partial thromboplastin time (PTT) of 23 seconds, and an INR of 0.9. Intravenous heparin therapy was initiated and titrated to a PTT of 50 seconds to 80 seconds. Warfarin was also continued, and an INR of 1.7 was achieved in six days. However, the INR again began to decrease despite increasing doses of warfarin. Serum warfarin concentrations were undetectable. Since mesalamine was the only new drug added to this patient's regimen prior to hospitalization, it was discontinued. The next day the INR was 1.8 and increased to 2.1 the following day .
Mesalamine Overview
-
Mesalamine is used to treat ulcerative colitis (a condition which causes swelling and sores in the lining of the colon [large intestine] and rectum) and also to maintain improvement of ulcerative colitis symptoms. Mesalamine is in a class of medications called anti-inflammatory agents. It works by stopping the body from producing a certain substance that may cause inflammation.
Warfarin Overview
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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.