Medical Research

CBD & Cytochrome P450

Written by Colby McCoy

Since the precipitous introduction of cannabidiol (CBD) into the marketplace, numerous clinical studies have been launched to further explore the medicinal potential of this cannabinoid for conditions like cancer, anxiety, and others. And while CBD is largely considered safe, it is important to recognize that, like any other bioactive substance, it interacts with the body in many different ways. In fact, CBD is metabolized in the liver by cytochrome P450 (CYP450), a type of enzyme that breaks down over 60 percent of prescription medications. Therefore, CBD can complicate the effects of these other medications when used together.[1]

Seminal research discovered that CBD inactivates the 2C and 3A subfamilies of CYP450.[2] In fact, one study found that CBD reduced 2C and 3A enzyme activity by more than 80%. In particular, 2C enzymes were three times as sensitive to low dosages of CBD in comparison to 3A enzymes. Consequent studies have shown that CBD can directly influence the effectiveness and potency of prescription medications through this pathway.

Another study looked at the interaction between CBD and a specific enzyme subfamily of 2C19. The results echoed the findings of earlier studies in showing that CBD is an effective inhibitor of 2C19 in liver cells.[3] 2C19 is primarily responsible for metabolizing multiple medications including diazepam (used for anxiety disorders and seizures) and escitalopram (used as an anti-depressant), just to name a few.

These findings certainly have far reaching consequences for CBD as a medicine, as several different classes of medications have been shown to interact with CBD. However, it’s important to note that many different factors affect CBD absorption and therefore each person requires a tailored cannabinoid medicine plan that best fits their needs. Therefore, it is always important to discuss CBD with your health care provider before initiating use. While you should certainly understand the risk associated with CBD interactions with other medications, you can work with your health care provider to plan an effective and safe course of treatment.

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  1. Iffland K & Grotenhermen F. An update on safety and side effects of cannabidiol: A review of clinical data and relevant animal studies. Cannabis Cannabinoid Res. 2017;2(1):139-154.
  2. Bornheim LM, et al. Characterization of cannabidiol-mediated cytochrome P450 inactivation. Biochemical Pharmacology. 1993;45(6):1323–1331.
  3. Jiang R, et al. Cannabidiol is a potent inhibitor of the catalytic activity of cytochrome P450 2C19. Drug Metabolism and Pharmacokinetics. 2013;28(4):332-338.

About the author

Colby McCoy

Colby McCoy is a recent graduate of the University of Georgia who has written for non-profits, marketing firms, and personal blogs. When not writing he can be found trekking the mountain ranges around Seattle, WA, with his two pups Harry and Riley.