CBD and Blood Thinners; is Warfarin and CBD a dangerous combination?

Every year millions of people in the United States take anticoagulants, widely known as ‘blood thinners’. The most commonly prescribed anticoagulant is a drug called Warfarin, but despite its popularity, many people are unaware of how CBD and anticoagulants can impact one another when taken together. Warfarin has two main isoforms (S and R) that are metabolized through the CYP hepatic enzyme complex. S-Warfarin is predominantly metabolized via the enzyme CYP2C9, while CYP3A4 is the dominant enzyme responsible for breaking down R-Warfarin.

Similarly to Warfarin, CBD is processed by way of the CYP enzyme complex. There are seven major isoforms involved in CBD metabolism, five of which are involved in breaking down warfarin, mainly CYP2C9 and CYP3A4.

Because of this, CBD and anticoagulants like Warfarin must compete for enzymes in the same metabolic pathway in order to metabolize. CBD is a more potent competitor of the two, and so the CBD molecules bind first, leaving behind an excess Warfarin in the system that didn’t get broken down. Over time, Warfarin in an individual’s system can build up. So while these two compounds don’t necessarily interact, they do affect each other.

When there is a build up of anticoagulants in someone’s system from daily use, it can lead to a rise in Internal Normalized Ratio (INR). When INR is too low, blood clots are not prevented, (which is why an anticoagulant like Warfarin would be prescribed). When INR is too high, there is an increased risk for bleeding.

Anyone who wants the benefits of CBD but is taking warfarin should consult their doctors and closely monitor INR. Anyone taking medication should always consult their health practitioner before implementing CBD into a daily routine.