THC, or tetrahydrocannabinol, is the primary psychoactive compound in the cannabis plant. It has been investigated for its potential medical benefits, including its ability to treat conditions like seizures, multiple sclerosis, and appetite loss. However, THC can also interact with blood thinning medications, which are used to prevent blood clots from forming and to treat conditions like atrial fibrillation, stroke, and venous thromboembolism.
In theory, THC could thin the blood by causing platelets in the bloodstream to aggregate, which is necessary for blood clot formation. However, to date, there have been no human studies published on this effect, and clinical trials have failed to show a significant decrease in blood clots when THC is taken in dosages commonly used for medical purposes.
When THC is administered alongside blood thinning agents, it may prolong the activation of these agents, potentially leading to enhanced anticoagulant effects and an increased risk of bleeding. In one clinical case report, a patient with mechanical valves who took an oral solution containing 900 mg THC daily and warfarin experienced a significant decrease in INR (the international normalized ratio), indicating increased blood thinness. Upon reducing the dose of warfarin by 30%, the patient's INR returned to normal, highlighting the interaction between THC and warfarin.
These interactions are particularly concerning for individuals with artificial heart valves, who are at heightened risk of developing strokes due to the formation of clots. They may also be at greater risk of bleeding complications from other interventions, including dental procedures or major surgeries., there is no published evidence to suggest that THC is a suitable or safe blood thinner, and its interaction with blood thinning medications has led to concerns about bleeding risks. While there is some preliminary research involving animal models or test tube experiments, the clinical significance of these findings in humans is unclear.
Cannabis as a whole, including THC and CBD, has not been consistently shown to thin the blood in controlled human studies. In contrast, certain components of cannabis, particularly CBD, may actually have a beneficial effect on blood coagulation. For example, a 2019 study in rats showed that both CBD and THC could improve resistance to coagulation in a model of vascular injury. Additionally, CBD has been shown to inhibit the activity of platelet aggregation in vitro, which could potentially reduce the likelihood of blood clots.
However, the potential benefits of CBD in cardioembolic disorders have not been consistently demonstrated in human studies, and studies have not addressed the issue of bleeding risks when CBD is taken alongside blood thinning medications. Therefore, the use of CBD or any other cannabis product in people requiring blood thinning therapy is still discouraged, and further research is needed., based on current understandings, THC does not appear to thin blood in humans, and its interaction with blood thinning medications has caused concerns about increased bleeding risk. While the potential benefits of other components of botanical cannabis have not been systematically assessed, CBD appears to have antiplatelet properties that could potentially minimize the risk of blood clots. Larger, well-designed human clinical trails studying the effects of CBD, THC, and other components of cannabis are needed to provide a clearer picture of their potential benefits and risks. Until then, there is no recommendation for or against using THC for blood thinning purposes in people requiring blood thinning therapy.
