Glucosamine - Warfarin Interaction
Herbal: Glucosamine
Drug: Warfarin
Brand names:
Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 23, 2024
Interaction Details
Warfarin is classified as belonging to the following category: Warfarin (Coumadin)
Glucosamine might increase the anticoagulant effects of warfarin and increase the risk of bruising and bleeding.
In two individual case reports, glucosamine/chondroitin combinations were associated with a significant increase in international normalized ratio (INR) in patients previously stabilized on warfarin. In one case, the increase in INR occurred only after tripling the dose of a glucosamine/chondroitin supplement from 500 mg/400 mg daily to 1500/1200 mg daily. Additionally, 20 voluntary case reports to the U.S. Food & Drug Administration (FDA) have linked glucosamine plus chondroitin with increased INR, bruising, and bleeding in patients who were also taking warfarin. There have also been 20 additional case reports to the World Health Organization (WHO) that link glucosamine alone to increased INR in patients taking warfarin. The mechanism of this interaction is unclear. Glucosamine is a small component of heparin, but is not thought to have anticoagulant activity; however, animal research suggests that it might have antiplatelet activity.
Interaction Rating
Likelihood of Occurrence
ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
References
- Rozenfeld V, Crain JL, Callahan AK. Possible augmentation of warfarin effect by glucosamine-chondroitin. Am J Health Syst Pharm 2004;61:306-307.
- Knudsen J, Sokol GH. Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: Case report and review of the literature and MedWatch database. Pharmacotherapy 2008;28:540-8.
- Yue QY, Strandell J, Myrberg O. Concomitant use of glucosamine potentiates the effect of warfarin. Jan 2006. Drug Safety 29(10):911-1010.
Glucosamine Overview
Glucosamine is a natural compound found in the body, particularly in the fluid that surrounds joints. It is often used as a dietary supplement to help with joint health, particularly for conditions such as osteoarthritis. Glucosamine is believed to work by helping to reduce inflammation, promoting the repair of damaged cartilage, and slowing down the loss of cartilage.
There are several different forms of glucosamine supplements, including glucosamine sulfate, glucosamine hydrochloride, and N-acetyl-glucosamine. Glucosamine sulfate is the most commonly used form in supplements. It is important to note that glucosamine sulfate is derived from shellfish (specifically the exoskeletons of shrimp, lobster, and crabs) and can be problematic for people with shellfish allergies.
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.
Glucosamine - More Interactions
Glucosamine interacts with 168 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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Parts of this content are provided by the Therapeutic Research Center, LLC.
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.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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