Cannabis and Drug Interactions
People often wonder whether their other prescription medicines will interact with cannabis and whether they need to adjust their dosages or strategies for other medicines when they take them together. The science regarding drug-drug interactions and cannabis is still young. Lacking comprehensive clinical trials, most recommendations are currently based on theoretical concerns and some case reports.
These concerns are highlighted in patients with more advanced age, where multiple medications are often combined. Medical cannabis can be used safely in most cases but requires a little more understanding.
Luckily, there are now online tools available to help you and your other healthcare providers evaluate whether your medical cannabis could interact with other medicines you are already taking. CLICK HERE or HERE for good examples.
Always discuss your use of medical cannabis with any healthcare provider who prescribes your other medications and with your dispensary pharmacist. Their prescriptions and monitoring plans may sometimes be affected. Consulting with a healthcare provider skilled and experienced in medical marijuana therapy is essential to safety.
While low to moderate medical cannabis consumption is unlikely to cause concern with most medicines, there are some exceptions. Medicines such as sedatives, anxiety medicines, antidepressants, pain medicines, and anti-seizure medicines may have an additive effect with cannabis. This might cause an increased clinical effect, reducing their safety and increasing side effects. For other medicines (e.g., Tamoxifen), cannabis may cause increased metabolism and elimination, thereby reducing their clinical effectiveness.
For most medicines, these concerns are relatively manageable. However, one exception is blood thinner medicine (e.g., Coumadin, Plavix, and heparin). These medicines have a very narrow range of clinical effectiveness. Too little blood thinning means inadequate protection against the risk of clotting. Too much blood thinning may increase your risk of bleeding. This is why you are monitored regularly when taking these medicines. Because of the importance of these consequences and because cannabis may affect these medicines, it is essential to discuss your cannabis therapy with the healthcare provider who prescribed it to avoid serious complications such as stroke, heart attack, or bleeding.
Use the Tools
We recommend using the tools and resources above to check all your medicines against the known or theoretical risks of drug-drug interactions. Using this information can help you facilitate a conversation with your doctor about any particular concerns or any indicated need for changes.
Dr. Nicholas Marsh has been a respected board-certified anesthesiologist in Northern Virginia for over 35 years. Recognized as a top doctor by FindaTopDoc.com, his vision for providing top-quality medical services is driven by his passion for patient comfort and dignity.