CBD Oil & Drug Interactions: A Complete Guide

CBD Oil Drug Interactions Header

CBD and other compounds in hemp oil may interact with a wide range of drugs. If you are taking or plan on taking any medications and wish to begin using a CBD product of any kind, be sure to talk with your doctor first.

Since its explosion into the mainstream consciousness in 2013, Cannabidiol (CBD) has quickly become a star cannabis compound thanks to its wide-ranging therapeutic benefits. CBD-rich products like capsules and tinctures are quickly growing in popularity thanks to their effectiveness and minimal side effects.

CBD is widely considered safe to use, well-tolerated (even in children and animals), and non-addictive (even anti-addictive). What is not widely discussed is the way that CBD oil is metabolized by the body can have a significant impact on the processing of other drugs.

What is the Cytochrome P-450 System?

The cytochrome P-450 system is found within the liver and is responsible for metabolizing over 60% of pharmaceutical drugs available on the market today. Within this system, there are more than 50 enzymes that process and eliminate toxins.

The rate at which drugs are processed by this system plays a key role in helping doctors determine the appropriate dosing for a given medication. Changes to the way drugs are metabolized may occur if this system is not operating normally due to health issues or the consumption of other drugs.

Many compounds found in hemp oil are also processed by the P-450 system. For example, THC induces CYP1A2, reducing the levels of drugs metabolized by this enzyme. CBD inhibits CYP3A4 and CYP2D6, increasing the levels of drugs metabolized by these isoenzymes. (R)

This means that when consuming CBD products, many other drugs to take longer than normal to be processed by the body. This can result in negative side effects and complications. On the flip side, these interactions can be positive. These interactions can be used to lower dosage requirements, mitigate side effects, and improve the quality of life in some patients.

The Grapefruit Test: An Easy CBD-Drug Interaction Reference

Grapefruit Test

You may have hears that physicians often warn their patients not to eat grapefruit before taking many medications. This is because several of the compounds in grapefruit also inhibit the cytochrome P450 system just like CBD does. CBD, however, turns out to be a more potent inhibitor than compounds in grapefruit like bergapten (the strongest of several grapefruit components that inhibit this system).

To make things easy, the grapefruit test is a great reference point for cannabidiol interactions. If your doctor has warned you about consuming grapefruit with any of your medications, it is a strong sign that you need to talk with your doctor about taking that medication in tandem with CBD oil.

Known CBD Oil & Pharmaceutical Drug Interactions

As we mentioned above, the number of drugs processed by Cytochrome P450 is large. Luckily the Indiana University School of Medicine has produced a handy chart which outlines the drugs known to interact with this system. If you're on any of the following medications, be sure to talk with a medical professional before beginning a CBD supplementation routine:

  • NSAIDs (ibuprofen)
  • Oral Hypoglycemics
  • Angiotensin II Blockers
  • Proton-Pump Inhibitors (PPIs)
  • Anti-Epileptics
  • Estrogen Modulators (Tamoxifen)
  • Beta Blockers
  • Antidepressants (SSRIs, SNRIs, MAOIs)
  • Antipsychotics
  • Anesthetics
  • Blood Thinners (Warfarin)
  • Sedatives (Clobazam)
  • Macrolide Antibiotics
  • Anti-arrhythmics
  • Benzodiazepines
  • Immune Modulators
  • HIV Antivirals
  • Prokinetics
  • Antihistamines
  • Calcium Channel Blockers
  • HMG CoA Reductase Inhibitors
  • PDE-5 Inhibitors

Alcohol, Cannabis, & CBD Oil

Alcoholic Drink

As the popularity of cannabidiol continues to rise and the prohibition on marijuana use lifts, the chance that cannabis and alcohol will be consumed together continues to rise. The nightlife industry has adopted CBD as an ingredient, the beer industry is producing cannabis beer, and more people around the world are gaining access to marijuana for legal recreational use.

What is not widely understood is the effects of combining these two popular substances. Similar to the drugs we discussed above, alcohol depends on specific metabolic pathways in the body to be processed.

Specifically, the substance relies on the enzymes alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) to be processed under normal conditions. For those who binge drink or have chronic alcohol consumption patterns, the cytochrome P-450 system gets involved, specifically the CYP2E1 enzyme.

Cannabis compounds like CBD and THC are processed through the same pathways as alcohol. Anecdotal evidence and research clearly show a strong interaction between consuming alcohol and cannabis together. While no studies show serious direct health threats from consuming the two together, there are implications that make the decision to consume cannabis products and alcohol together something to carefully consider:

  • Consuming alcohol and marijuana together increases THC levels in the blood, but THC does not increase blood alcohol levels. (R)
  • When CBD is combined with alcohol far lower blood alcohol levels were observed, but the effects of alcohol were not influenced. (R)
  • THC has been shown to encourage alcohol consumption, while CBD has been shown to decrease it. (R)
  • CBD has been shown to protect the liver from damage due to binge drinking (R), prevents against alcohol-induced neurodegeneration (R), and shows therapeutic potential in the treatment of alcoholic liver diseases associated with inflammation, oxidative stress, and steatosis. (R)
  • CBD is observed to reduce the reinforcing properties, motivation, and relapse of alcohol use, strongly suggesting it may be useful in the treatment of alcohol use disorders. (R)

Opioids & Cannabis: A Promising Combination


Today, many studies suggest a bidirectional modulatory relationship between the body's opioid system and cannabinoid system. Though the specific interactions between these to have yet to be specifically documented, initial research and anecdotal evidence is encouraging to say the least. What is certain is that both systems can play a key role in reducing the perception of pain.

It is no secret that in the search for relief from pain, opiates kill thousands of people each year and have a high risk of abuse. Cannabis, on the other hand, is widely recognized by medical professionals for its safe use in relieving pain. While both have their uses, and one may not simply be an absolute substitute for the other, taking the two in tandem may have an encouraging future.

A study published in 2011 by Dr. Donald Abrams, an oncologist from UC San Francisco found no significant changes in opioid blood level concentrations when cannabis is consumed. In addition, patients in the test reported a 27% decrease in pain following the administration of cannabis. These results point to cannabis as a safe tool to augment the pain-relieving effects of opiates.

With widespread use, addition and death from opioid use earning the label of 'crisis', cannabis could be a helpful tool in reducing impact from these drugs. Consuming the two together may allow for the treatment of patients with lower doses of opioids, reducing the risk of dependency and limiting side effects. Diving deeper, cannabis may be a multi-purpose tool as THC was shown to significantly enhance the painkilling effects of opiates, while CBD showed promise for reducing withdrawal and dependence.

Caffeine & CBD Oil

Cup of Coffee

Perhaps one of the most common combinations for CBD users is the consumption of caffeine (via coffee or tea) alongside CBD.

While scientific research on the subject is limited, it is well known that both CBD and caffeine act on the adenosine receptors. Caffeine is an adenosine inhibitor, meaning it may diminish CBD's medicinal properties, but the impact is unknown.

It is likely that the combination of the two substances is not problematic. To make the impact even lower, those seeking to supplement CBD oil for serious medical conditions would likely choose a more accurately dosed method of ingesting hemp oil.

One additional note is that caffeine too is metabolized by the CYP450 enzyme, specifically CYP1A2. This could lead to a slower rate of caffeine processing through the body, resulting in a more drawn-out caffeine effect.

The lack of side effects between the interaction between these two substances can also be anecdotally confirmed as the rise of CBD-infused coffee permeates popular culture.

Originally Published: October 26, 2018 | Last Updated: November 30, 2018

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