Interactions Between Blood Thinners and Cannabis


Interactions Between Blood Thinners and Cannabis

As states continue to legalize the use of medical marijuana, its potential as an effective treatment for diseases continues to be researched. One of the most important aspects to understand is how cannabis may interact with blood thinners and other medications.

Commonly, medical marijuana patients are trying to decrease their use of pain, sleep, or anxiety medications. In the process of decreasing some of these medications, patients are not aware that other interactions with cannabis can occur.

If you are taking blood thinners, it is especially important to understand how cannabis interacts with your medications. Although cannabis is not typically used as a blood thinner or for related cardiovascular conditions, studies have shown that using cannabis while on a blood thinner can change how these drugs work in the body and may lead to some negative side effects.

Although many patients on blood thinners do use cannabis without ill effects, always use caution and follow the guidance of an experienced healthcare provider. If you’re currently taking blood thinner medication and are considering medical cannabis, here is what you need to know about potential interactions between the two.

How Blood Thinners and Cannabis Interact



The liver enzymes in our body that break down blood thinners also break down the medicinal compounds found in marijuana. Taking them simultaneously can potentially modulate the effectiveness of your blood thinners. Cannabis may compete for the enzymes that metabolize blood thinners; inhibiting these enzymes may increase anticoagulant plasma concentrations, potentially increasing the risk of bleeding

For example, a recent study demonstrated that cannabis can increase the levels of warfarin -one of the most widely used anticoagulants- in the body, and can potentially lead to excessive bleeding. Another study from 2017 found a “clinically significant” interaction between pharmaceutical-grade CBD and warfarin.

CBD has also been shown to inhibit the enzymes responsible for metabolizing clopidogrel, an antiplatelet medication commonly sold with the brand name Plavix. This interaction could lead to suboptimal absorption of the drug, and can potentially increase the risk of stroke.

You should be wary of similar side effects if using cannabis in conjunction with blood thinners like Eliquis, Xarelto, and Coumadin. Watch out for symptoms indicating excessive bleeding, including:

  • Bleeding Gums
  • Nosebleeds
  • Bruising
  • Petechiae (pinpoint red dots on the skin)
  • Blood in urine or stool
  • Heavy menstrual bleeding
  • Unusual bleeding from small cuts
  • Slow wound healing

What About Aspirin?


Most commonly used for relieving minor aches and pains, aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that also has blood-thinning properties. It is often taken daily in low doses as preventative medicine for people at high risk of heart attacks or strokes.

Considering its blood-thinning properties, is it safe to take over-the-counter aspirin while using cannabis? So far, the specific effects of combining cannabis with aspirin have not been established in any scientific study. However, CBD has been shown to inhibit the enzymes responsible for metabolizing aspirin, leading to an overall increase in processing times. If you are using low-dose aspirin regularly as a blood thinner, the consumption of cannabis, especially CBD, is not recommended until more long-term studies can further identify any potential interactions.

Talk With a Doctor


Because cannabis is an anticoagulant and has shown the potential to interact with blood-thinning medications, patients on blood thinners should use caution when adding medical marijuana to their routine, and be sure to consult with a physician.

Are you interested in treating your symptoms with medical marijuana, but want to know more about potential interactions between cannabis and your medications? Book an appointment with Heally, and we’ll connect you with a doctor in your state for a telehealth appointment to answer your questions and to get started on an application for your medical marijuana card.


Interested in using cannabis as an alternative treatment? Get your cannabis card with a licensed physician.

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