Chitosan - Warfarin Interaction
Herbal: Chitosan
Drug: Warfarin
Brand names:
Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jul 22, 2023
Interaction Details
Warfarin is classified as belonging to the following category: Warfarin (Coumadin)
Theoretically, chitosan might increase the risk of bleeding when taken with warfarin.
In a case report, a patient taking warfarin had a significantly increased international normalized ratio (INR) after starting chitosan 1200 mg daily. The INR normalized after chitosan was discontinued and vitamin K was administered. The patient once again started taking chitosan and again had a significant increase in INR. The INR stabilized again once chitosan was discontinued. Researchers theorize that this interaction might occur because chitosan decreases absorption of fat-soluble vitamins, including vitamin K, which could increase the anticoagulant effect of warfarin.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Huang SS, Sung SH, Chiang CE. Chitosan potentiation of warfarin effect. Ann Pharmacother 2007;41:1912-4.
Chitosan Overview
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.
Chitosan - More Interactions
Chitosan interacts with 3 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
Unknown | No interactions have been reported or no interaction data is currently available. |
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DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
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Drug descriptions are provided by MedlinePlus.