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Life Force Blog

CBD Drug Interactions

Published on 16th August 2019


CBD oil is the multimillion pound nutraceutical changing the face of natural health supplements. In the UK alone, more people take CBD than the vitamin C and D market combined. But CBD is not a normal nutritional supplement and may interact with some prescribed medications. Let’s take a look at whether CBD drug interactions could be a problem for you.


The last 5 years has seen a tremendous boom in the CBD oil market with approximately 1.3 million people using the cannabinoid hemp extract in the UK. While there are no official statistics, it’s likely a large number of these regular CBD users also take some kind of prescription medication as well. 


Most nutritional supplements do not interact with over the counter or prescribed medication. However, with CBD this may not be the case.


CBD - a Complex Molecule

CBD, otherwise known as Cannabidiol, is a surprisingly complex molecule. Scientists studying how CBD affects the body have found that it acts on multiple molecular pathways at once. This may explain why people anecdotally report how CBD has improved symptoms from a host of seemingly unrelated conditions.


CBD is broken down in the body (or metabolized) by the cytochrome P450 enzyme, which by oxidizing the cannabinoid makes it water soluble and therefore easier for the kidneys to filter out. 


CBD is not only metabolized by the cytochrome P450 enzyme, it also likes to knock out the competition, preventing other compounds from being broken down by the enzyme as well. 


What this means is that if you are taking medication that is broken down by the cytochrome P450 enzyme alongside CBD oil, your prescribed medication may remain for longer in your blood, potentially leading to toxic build up or an increase in the medication’s side effects.  


CBD and Anti-Seizure Medication

This effect was noted in the clinical research leading up to the approval of Epidiolex, the purified CBD drug for rare types of epilepsy in children. When administered at high doses (between 5-50mg per kilo body weight), CBD caused higher blood plasma levels of the anti-seizure drugs clobazam, rufinamide, topiramate, zonisamide, and eslicarbazepine. As a result, subjects reporting increased side effects such as sleepiness. When combined with Valproate, another commonly prescribed anti-seizure med, abnormal liver function was noted.


Some concern has also been expressed about taking CBD alongside the anticoagulant Warfarin, after a patient using Epidiolex experienced elevated levels in their blood. In this case, the doctor could readjust the patient’s Warfarin dose in order to remain within the therapeutic range for optimum blood clotting action. For the paper’s authors, these findings highlight “the importance of monitoring appropriate laboratory work in patients receiving concomitant cannabis products and other pharmaceuticals, particularly those metabolized by the cytochrome P450 enzyme system.” 


Can I Take CBD With My Medication?

We cannot give any medical advice, but evidence suggests that the dosage usually taken by CBD oil consumers is far lower than that administered to patients taking Epidiolex. Indeed, studies suggest that low doses of CBD do not prevent other drugs from being broken down by the cytochrome P450 enzyme. That said, about 60% of drugs available on the market are metabolized by this enzyme, including commonly prescribed psyche medication like Clonazepam, Valium, Xanax, and many antihistamines, antiretrovirals, and steroids. 


If you would like to check whether your prescribed medication is metabolized by the cytochrome P450 enzyme, here is a comprehensive list. However, it is always advisable to talk to your GP if you are considering taking CBD oil and are already taking prescribed medication. 


Some final advice if you decide to buy CBD oil to support your overall health: always choose a certified organic CBD oil that third party lab tests results proving not only Cannabidiol content, but that your CBD oil is free from unwanted heavy metals, pesticides, and mould. At Spirit of Hemp we value your health, going the extra mile to provide you with the cleanest, safest, and most cannabinoid-rich full spectrum CBD oil.