CBD And Drug Interactions: Everything You Need To Know

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A plethora of studies successfully demonstrates cannabidiol’s (CBD) potential to treat a host of conditions and disorders effectively. While more in-depth studies are required to substantiate any health claim, current research suggests that CBD therapeutics could potentially help manage symptoms directly associated with chronic pain, depression, anxiety, and inflammation, as well as a multitude of other ailments. While CBD is generally well tolerated with a good safety profile, it could react negatively with certain medications. This article discusses everything you need to know about commonly reported CBD side-effects and possible CBD-related drug interactions.

CBD Side-Effects

To date, CBD has never been linked to any medical emergencies and reported adverse side-effects are few and easily manageable. According to a 2018 medical study in which 2,490 respondents were represented, the most common CBD-related side-effects included dry mouth (11.12%), euphoria (6.43%), hunger (6.35%), and sedation/fatigue (1.78%). 

Despite its high safety profile and minimal side-effects, CBD demonstrates potential in interacting with pharmaceuticals and altering how the body metabolizes certain substances. For this reason, it is crucial to disclose all supplements and medications to a healthcare professional before adding CBD to your daily regimen. 

Drug Metabolism

Many commonly prescribed pharmaceutical medications, in addition to cannabinoids such as CBD and THC, are metabolized by a large class of liver enzymes known as cytochrome 450 (CYP450). These enzymes are tasked with the crucial function of converting foreign substances for elimination from the body. However, some chemical compounds affect CYP450, causing drug metabolism to speed up or slow down, directly altering how the body processes supplements or medications.   

CBD and Metabolic Enzymes

Cytochrome P450 3A4 (CYP3A4), a crucial enzyme within the CYP450 class, is specifically tasked with metabolizing more than 50% of pharmaceutical medications. Cannabinoids such as CBD can alter CYP3A4, inhibiting how effectively it can break down other chemical compounds. Alternatively, certain pharmaceuticals can inadvertently hinder the efficacy of CBD by increasing metabolic rate.

Slowly metabolizing medications could lead to exaggerated and potentially adverse effects, even when consuming a standard dose. However, if metabolized too quickly, the compound may no longer be at optimal strength for treating a health condition. Both case scenarios could promptly escalate to serious adverse side-effects and potential fatality. 

CBD and Grapefruit

The relationship between CBD and pharmaceutical medications is still not fully understood. However, since CBD and grapefruit have a similar effect on CYP450 enzymes, it would be good practice not to combine CBD with any pharmaceutical with a grapefruit warning without a healthcare professional’s consent.     

Grapefruit Warning

While studies analyzing how CBD reacts with common pharmaceuticals have yielded no definitive result, consumers prescribed medications with grapefruit warnings should consider avoiding CBD unless otherwise instructed by a healthcare professional. 

Grapefruit contains a chemical compound called furanocoumarin, which can neutralize CYP450 enzymes. This hindrance can drastically amplify the effects of certain medications to potentially dangerous levels. According to an article published by Drugs.com, some of the most commonly prescribed pharmaceuticals with grapefruit warnings include:

  • aliskiren (Tekturna) – also apple juice, orange juice
  • alprazolam (Xanax)
  • amiodarone (Pacerone)
  • atorvastatin (Lipitor)
  • carbamazepine (Tegretol)
  • cilostazol (Pletal)
  • clarithromycin (Biaxin)
  • cyclosporine (Gengraf, Neoral)
  • colchicine 
  • dronedarone (Multaq)
  • erythromycin (E.E.S., Eryped)
  • felodipine (Plendil)
  • fentanyl  
  • fentanyl transdermal system (Duragesic Skin Patch)
  • fexofenadine (Allegra)
  • flibanserin (Addyi)
  • indinavir (Crixivan)
  • loratadine (Claritin)
  • losartan (Cozaar)
  • lovastatin 
  • nilotinib (Tasigna)
  • naloxegol (Movantik)
  • palbociclib (Ibrance)
  • pazopanib (Votrient)
  • pimozide (Orap)
  • ranolazine (Ranexa)
  • saquinavir (Invirase, Fortovase)
  • sildenafil (Revatio, Viagra)
  • simvastatin (Zocor)
  • tadalafil (Adcirca, Cialis)
  • vardenafil (Levitra, Staxyn)
  • verapamil (Calan, Calan SR)
  • Warfarin

CBD and Drug Interactions

It is possible to consume CBD while on prescription medications if under your healthcare provider’s careful supervision. When doing so, your doctor may ask you to monitor yourself for any of the following potential adverse side-effects:

  • An onset of side-effects directly related to CBD
  • A decrease in the effectiveness of currently prescribed medications
  • New or increased medication side-effects

Drug Interactions Studies

Researchers continue their attempt to identify specific interactions directly stemming from CBD and a variety of medications. Despite various animal studies, it remains unclear whether similar results can be achieved in a human model. Fortunately, a few small clinical trials offer some insight into potential CBD drug interactions. 

A small study conducted in 2015 analyzed 25 children diagnosed with difficult-to-treat epilepsy. After administering clobazam and CBD to 13 participants, researchers concluded that the therapy was safe. However, they additionally recommended careful monitoring due to elevated levels of clobazam discovered during treatment. 

In research conducted in 2017, CBD in Epidiolex form was administered to 42 children and 39 adults already prescribed various antiepileptic drugs (AEDs). Researchers gradually increased the dose strength every other week while under careful supervision. Serum levels largely remained within the acceptable therapeutic range. However, participants prescribed desmethylclobazam and clobazam, when combined with Epidiolex, showed serum levels outside of the optimal therapeutic range. 

Speak with Your Doctor

It is essential to always consult with a healthcare professional before adding CBD or any other supplement to your daily regimen, especially if already prescribed pharmaceutical medications. Your doctor may be able to recommend a specific dosage and schedule that’s safe to take alongside your existing medications. Never discontinue your prescribed therapy in favor of CBD without consent from a healthcare professional.

Key Takeaways

CBD’s tolerability and safety profile is well established within the scientific community and is additionally endorsed by the World Health Organization. Despite its lack of serious adverse side-effects, researchers continue to study its potential drug interactions with a host of pharmaceutical medications. It remains good practice to avoid combining CBD with any pharmaceutical with a grapefruit warning until definitive proof is established. Always consult with a trained healthcare professional before adding CBD or any other supplemental product to your daily health regimen.



I am the owner and founder of CBD Review Lab. I started CBD Review Lab after having a positive experience with CBD and wanted to share my experience in hopes it would help others. I hope that this website is helpful to you in finding a CBD product that suits your needs. If you have any questions, please don’t hesitate to reach out.

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