Drug Interaction/CYP450

The vast majority of science indicates that CBD oil is safe for use and consumption, however there are a few well described adverse effects as well as drug interactions.  If not fully understood, you could be putting yourself or those to whom you sell CBD product in danger.  One of these risks is the inhibition of the cytochrome P450 enzyme system.


When calculating medication dosing and interactions, doctors make calculations using the average time it takes for various drugs and medications to be processed through the CYP450 system.  If only one drug is being processed and the system is healthy, these averages provide accurate dosing information.    Some medications and substances, such as CBD, affect the processing time within this system and can make certain drugs metabolize faster, or slower, than if they were on their own.  If the system is unhealthy, as with liver disease or other illness, drugs may also be metabolized at different rates.


Cannabidiol (CBD) is metabolized in the liver using the cytochrome P450 system. The P450 system is comprised of over 50 enzymes, with six of them metabolizing 90 percent of drugs.  CBD is metabolized by CYP2C29 and CYP3A.  This makes it vital to review all medications when someone is taking CBD so that drug interactions can be evaluated.


Cannabidiol can inhibit the cytochrome P450 systems ability to metabolize certain drugs and increase processing times.  Grapefruit, watercress, St John’s Wort, and goldenseal all have similar impacts.  When this inhibition occurs, higher levels of certain drugs can be in your system at one time, leading to unwanted side effects or overdose.  You should consult your doctor to ensure it is safe for you to supplement with CBD oil. However, many physicians are unfamiliar with CBD or its interactions and may simply say it is not safe without true knowledge of interactions.  Find a physician who is knowledgeable and willing to work with you.

Any Drug that is metabolized by the CYP450 enzyme could potentially interact with cannabidiol.  Below is a list of drugs known to use the CYP450 system:

  • Steroids

  • HMG CoA reductase inhibitors

  • Calcium channel blockers

  • Antihistamines

  • Prokinetics

  • HIV antivirals

  • Immune modulators

  • Benzodiazepines

  • Antiarrythmics

  • Antibiotics

  • Anesthetics

  • Antipsychotics

  • Antidepressants

  • Anti-epileptics

  • Beta blockers

  • PPIs

  • NSAIDs

  • Angiotensin II blockers

  • Oral hypoglycemic agents

  • Sulfonylureas


This list does not include all of the potential medications impacted by cannabidiol. Nor will every medication in the categories contained on this list will cause an interaction. For these reasons, you should consult with a medical professional before supplementing with CBD oil.



There are also certain drugs that are known as prodrugs.  These need to be metabolized to produce the version that produces the therapeutic result desired.  This can lead to too little of the active drug if the CYP450 system is inhibited by other drugs or agents.  For example, codeine is a prodrug that is metabolized to morphine.  Vyvance and Concerta also fall into this category.




Alcohol depends on a few different metabolic pathways in the human body, with the primary enzymes involved being:

In people who only drink socially or occasionally, ADH and ALDH metabolize all of the alcohol.  When binge drinking (or during chronic consumption of alcohol) CYP450 assists the overloaded ADH and ALDH pathways.


Here are some interesting information about alcohol and CBD oil (most of these studies were done in mice, others with only small numbers of human subjects):


  • The CB1 receptor is a significant player in the reinforcing and motivating attributes of alcohol. [S]

  • Combining alcohol and CBD results in significantly lower blood levels of alcohol. [S]

  • CBD reduces the reinforcement, motivation and relapse for alcohol. [S]

  • CBD protects the liver from damage done by binge-drinking alcohol. [S]

  • CBD prevents against alcohol-induced neurodegeneration. [S]

  • CBD attenuates alcohol-induced liver steatosis, metabolic dysregulation, inflammation and neutrophil-mediated injury. [S]

  • Cannabinoids have an effect on nearly all enzymes responsible for metabolizing alcohol. [S]

  • CB1 receptor agonists (THC) encourage alcohol consumption, while CB1 receptor antagonists (CBD) decrease it. [S]


While the pharmacokinetics of alcohol and CBD are not yet well-defined, we do know that CBD inhibits the CYP450 enzyme system which also plays a significant role in alcohol metabolism.  It has been additionally shown, in mice, that CBD alters levels of ADH and ALDH to varying degrees.  Most importantly, be mindful and cautious when mixing CBD and alcohol.




The most famous and commonly used psychoactive drug in the world is caffeine.  Because of the popularity of CBD, some companies are now combining the two.  It seems this combination may be beneficial. 


Caffeine is very similar to adenosine molecularly.  Adenosine activates the A2A receptor.  Caffeine binds the A2a receptor and inhibits the reuptake of adenosine.  When adenosine binds the A2a receptor it leads to what is known as the ‘rest and digest’ effect on the parasympathetic nervous system. CBD is a partial agonist of the A2a receptor, so the theory states that by combining caffeine and CBD, adenosine is blocked, which results in more stimulation but reduced anxiety (by means of CBD’s effect on other neurotransmitters).  Note that high amounts of CBD are more likely to cause drowsiness and sedation. 


Caffeine is metabolized by the same CYP450 system, therefore CBD causes a slowed excretion rate of caffeine, which can prolong the effects of caffeine.  This can prolong the effects of your morning coffee, but don’t overdo it and keep yourself up at night!

The statements on this website have not been evaluated by the Food and Drug Administration. The products discussed are not intended to diagnose, treat, cure or prevent any disease or ailment. CBDExpert™ assumes no responsibility for the improper use of these products. 


We recommend consulting with a qualified medical doctor or physician when preparing a treatment plan for any and all diseases or ailments prior to using or consuming CBD products. It is especially important for those who are pregnant, nursing, chronically ill, elderly or under the age of 18, and those currently taking medication or who have a medical condition, to discuss the use of these products with a medical doctor or physician prior to using or consuming CBD products.  


This website is intended to provide general information regarding CBD products and is not to be construed as medical advice or instruction. No physician-patient relationship exists between you and us by virtue of your use of this website.

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