Interactions of Cannabis (CBD/THC) and Medications
How do medicines and cannabis interact?
Cannabis use has been partially legalized in Germany. Even before legalization, marijuana and hashish were widely used in the population. For that reason, we want to point out possible interactions.
Wechselwirkung von Cannabis (CBD/THC) und Medikamenten: CBD und THC sind die zwei bekanntesten Wirkstoffe von mehr als hundert
Cannabinoiden in der Hanfpflanze
Already known, for example, is an interaction with the "blood thinner" Marcumar and its generics that is, drugs with the same active ingredient but a different brand name. Using cannabis while on Marcumar therapy can increase the risk of bleeding. This can be dangerous because as Marcumar patients know bleeding while taking Marcumar can be hard to stop. This applies not only to external bleeding but also to bleeding in the gastrointestinal tract. A similar interaction with cannabis is possible for another group of blood-thinning drugs, the direct oral anticoagulants (DOACs) such as Pradaxa (Dabigatran), Xarelto (Rivaroxaban) and Eliquis (Apixaban).
The opposite can happen when anticoagulation is achieved with Plavix (Clopidogrel). Here, cannabis can reduce the antithrombotic (blood-thinning) effect. In that case, the risk that blood clots will form is increased by using cannabis.
Similar interactions have been described or are suspected for many other medications. We used the example of blood thinners because that interaction is proven and blood thinners are commonly prescribed for cardiovascular diseases for example after heart attacks and strokes.
So that your high doesnt turn into a problem, please dont hesitate to ask your pharmacist about possible interactions with your medications if you plan to use cannabis.
Sources:
This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based data and is continuously updated (as of 12/2025).
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.
We hope you found the article helpful. For good blood pressure control, it's important to take your medications correctly. Our app BloodPressureDB will gladly remind you when to take them.
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