Inflammablog

Warfarin or the generic form Coumadin is a commonly used prescription drug that is used to prevent stroke in patient suffering from chronic atrial fibrillation, a heart valve replacement, and/or a recent heart attack. Warfarin is usually referred to as a "blood thinner" or anticoagulant because it keeps blood flowing smoothly throughout the body by decreasing the amount of clotting proteins in the blood. This medication is classified has having a low therapeutic index(i.e. there is a small margin between a normal recommended dose and a potentially lethal dose).
Since the topic this week is Anti-inflammatories and warfarin has a extremely high level of protein binding, there is a possibility that Warfarin may interact with NSAIDs. Along with the affinity for protein binding, it also can cause partial metabolic inactivation by prehepatic and hepatic CYP2C9. The medications that can cause adverse reactions include aspirin, ibuprofen, naproxen, and celecoxib(Celebrex). The complications start because the NSAID's and the COX-2 inhibitor are also extremely prone to bind to proteins in the blood(~99%) and can therefore displace the protein binding for warfarin. This can then lead to free blood levels of non-binded warfarin which can lead to the increased risk of GI or other types of hemorrhagic diseases.
Another factor that could lead to the increased GI bleeding is that each of these drugs can have an effect of the clotting profile of the blood such as inhibition of potassium dependent clotting factors suppressed by the Warfarin and the inhibition of the COX-1 in the platelets and GI mucosa caused by the NSAID's. It could be recommended then that NSAIDs should be avoided while taking anticoagulants such as Warfarin and Coumadin and to use a mild pain reliever such as Acetaminophen or Tramadol as the alternative.