Does CBD Interact with Prescription Drugs?

So you’ve heard that CBD might help with stress, sleep, or pain, but you also take medications for some of these issues. Is CBD safe to take with your other medications?

Well, the short answer is: it depends. The available data we have about CBD, or cannabidiol, is from an FDA- approved product called Epidiolex®, which is used for seizures.  We know that cannabidiol is metabolized by a class of enzymes called Cytochrome P450 enzymes, which are primarily found in the liver.1 These enzymes are responsible for metabolizing drugs and other compounds, and can be inhibited (turned down) or induced (turned up) by their substrates.  When drugs or chemicals interfere in this metabolism pathway, there can be unanticipated adverse reactions or therapeutic failures. 

CBD is a moderate INHIBITOR of a specific Cytochrome P450 enzyme called CYP2C19, meaning it turns down the activity of the enzyme.2  Therefore, when a drug that relies on CYP2C19 for its metabolism (like citalopram-an antidepressant- for example) is taken with CBD, the CBD INHIBITS the breakdown of citalopram and causes concentrations of the drug in the body to be higher. This could cause side effects and toxicities; or it could actually work to a patient’s advantage and allow the dosage of a pharmaceutical to be reduced. However, this should not be done without the advice and guidance of a prescriber. Therapy must be monitored. 

Also keep in mind that there are drugs that inhibit or induce the metabolism of CBD itself, making the given dose of CBD more effective, or less effective depending on the mechanism of the interaction. CBD is metabolized via CYP2C19 and CYP3A4 pathways.2 Strong CYP3A4 INDUCERS like St. John’s Wort or phenytoin may decrease the levels of CBD in the bloodstream, thereby weakening its desired effect.

Other potential interactions with CBD exist with drugs like: blood thinners, seizure medication, SSRI’s, anti-anxiety medication, anti-spasmodics, CNS depressants, antacids, immunosuppressants, and anti-fungals.  Many pharmaceuticals are metabolized by CYP450, as you can see. 

Confounding the metabolism of Cytochrome P450 substrates is the fact that there can be genetic variability in the way we metabolize drugs, too. This is called polymorphism, and it influences a patient’s response to a particular drug.3  Certain ethnic groups actually metabolize drugs differently, and this should be taken into account as well.   A dose that works for one person may not be optimal for another. We are continuing to learn more about this in the field of pharmacogenomics.

The bottom line is that if you are taking medications along with CBD, it’s important to disclose this to your doctor or healthcare provider.  Find a provider who is knowledgeable about CBD, and tell the provider about all the drugs, vitamins, and supplements you use. The right provider will help you select the best product, starting dose, and dosing frequency for your individual needs.

At CBD Plaza we have a team of naturopathic doctors that would be happy to have a consultation with you to help you figure out if CBD is right for you, and how CBD may interact with other medications you are taking. Go here to speak to Dr. Sarah Myers. 

About the Author

Dr. Sarah Myers, PharmD is a community pharmacist who helps her patients make informed choices. With a background in medication management, nutrient depletions, and complementary and alternative medicine, she can guide patients to wellness with an integrative approach. She enjoys cycling, yoga, and teaching others how to live their healthiest lives.

References

  1. Rongrong, J., Yamaori, S., Takeda, S., et al. Identification of cytochrome P450 enzymes responsible for metabolism of cannabidiol by human liver microsomes. Life Sciences. 2011; 89(5-6):165-70 https://doi.org/10.1016/j.lfs.2011.05.018.
  2. Brown JD, Winterstein AG. Potential Adverse Drug Events and Drug–Drug Interactions with Medical and Consumer Cannabidiol (CBD) Use. Journal of Clinical Medicine. 2019; 8(7):989. https://doi.org/10.3390/jcm8070989
  1.   Zhou, ZW., Chen, XW., Sneed, K.B. et al. Clinical Association Between Pharmacogenomics and Adverse Drug Reactions. Drugs 75589–631 (2015). https://doi.org/10.1007/s40265-015-0375-0
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