This article was written and vetted for scientific accuracy by Dr. Omer Rashid.
We all know that CBD can do wonders for our well-being, but could you be putting yourself at risk by mixing CBD products with other prescription or over-the-counter medications? Whether you are currently relying on other medication3s or plan to in the future, it is very important that you do your due diligence by researching possible drug and CBD interactions. Otherwise, you may be putting yourself at risk of adverse side effects or decreased medicinal effects.
In this article, we will go over the science behind CBD and drug interactions, as well as a list of common CBD and drug interactions to look out for.
Is CBD Safe?
CBD, also known as cannabidiol, is one of the most significant constituents of cannabis. Unlike cannabis, CBD on its own does not cause euphoria or dependence. This lack of psychoactive effects, paired with the fact that it is known for its anti-inflammatory properties and ability to shut down pain receptors in the brain, makes it a popular pain management tool.
CBD products are incredibly safe to use—in fact, the World Health Organization itself states that CBD use is generally well-tolerated and does not pose any health risk. However, it’s worth noting that this lack of warning applies to pure CBD and does not apply to CBD products that have additional constituents added to them. These products need to be carefully analyzed before use. The safety of CBD also does not cancel out the adverse side effects that it can have when combined with other drugs.
The best way to protect yourself while using CBD is twofold. Firstly, in order to minimize the risk of using CBD, it is best to use CBD oils that are high in cultivar whole-plant extracts and have little or no impurities. CBD oil extracted from high cultivar strains of the cannabis plant has negligible levels of Tetrahydrocannabinol (THC) as compared to other strains. THC is the constituent of cannabis that imparts euphoria and may also result in some side effects.
Secondly, it is vital to always keep your doctor in the loop on both your current CBD use as well as your prospective CBD use, in order to avoid potential side effects. It also doesn’t hurt to familiarize yourself with the most common drugs that CBD can interact with—we’ve included a list below.
Why Does CBD Interact With Medications?
With everything that we ingest, metabolization starts in the stomach—but the most crucial metabolic phase of 60% of the drugs we ingest takes place in the liver. This means that the liver is responsible for making the active ingredients of any drugs you take available in the bloodstream. Once these metabolized active ingredients are able to travel through our blood, they can then reach numerous organ tissues in an efficacious form.
As the general metabolic center for drugs, the liver also helps in eliminating any unwanted drug byproducts that are produced because of the chemical reactions that take place in the liver. These byproducts are transformed by the liver into a form that makes it easier for the body system to flush out.
The liver has a set of enzymes (CYPs) that help to metabolize various substances. However, some specific substances can engage these enzymes and hamper their ability to metabolize other drugs. This in turn increases the concentration of the non-metabolized drugs in the body, which can lead to unwanted effects. CBD is one of the substances that can potentially interact with CYPs, meaning that it can result in the degradation of the metabolism of certain drugs.
There’s one caveat: some CBD products such as CBD oils are taken sublingually, which means that they enter the bloodstream without encountering the liver and its chemical reactions. CBD oil will not interact with drugs in these cases. However, if you are ingesting CBD oil and medications this may lead to CBD oil drug interactions due to the involvement of the liver. We’re not sure of just how much—most of the research that has been done so far to determine the effects of CBD oil on the liver involves mice that were exposed to much higher doses than what humans would normally consume.
Studies were also conducted on mice to determine the effects of CBD oil on kidneys. No evidence of any adverse effects has been stated. In fact, these studies actually revealed some beneficial effects of CBD on kidneys such as prevention of a particular type of nephrotoxicity.
Common CBD Drug Interactions
As stated earlier, CBD is generally well-tolerated and adverse effects that are reported generally stem from its interaction with other drugs including both existing medications as well as substances that are mixed with the CBD you ingest. However, there are some common CBD drug interactions that you should be aware of.
The following is a list of popular medications that can be affected by CBD use. In all of the following CBD drug interactions, the most common concern is that CBD can effectively raise the levels of certain drugs in the body’s system, resulting in toxicity or amplified side effects.
CBD and Anxiety and Depression Medications
Drugs like Xanax or Ativan, termed benzodiazepines, are widely prescribed to treat anxiety. CBD can elevate the concentrations of these drugs in the body which can then amplify the sedative effects of these drugs. Increased drowsiness may also be experienced while using CBD with some supplements commonly used to treat depressive disorders such as St. John’s wort, kava, and melatonin.
CBD and Blood Thinning Medications
CBD and Thyroid Medications
A thyroid medication named levothyroxine has also been found to be unsafe for use in conjunction with CBD. You should always consult your doctor before mixing these medications.
CBD and Seizure Medications
Anti-epileptics such as Clobazam are widely used to treat seizures in children. CBD is also considered an effective treatment of seizures in children. However, if both CBD and Clobazam are being used simultaneously, clobazam levels can increase, causing an overdose of the drug. CBD use alongside epileptics should be avoided in general.
CBD and Satins (Cholesterol Medications)
If you are on cholesterol medications, also known as statins, you should be aware that CBD can increase the levels of these drugs in the body. CBD can increase the accumulation of atorvastatin (Lipitor) and simvastatin (Zocor) in the body system which can have dangerous effects
CBD and Blood Pressure Medications
Certain medications that are used to treat high blood pressure (such as nifedipine, which is sold as Adalat CC and Procardia) can fall victim to what is known as the “grapefruit rule” and should therefore not be taken alongside CBD.
The grapefruit rule—also known as the grapefruit warning—can actually be a handy way to scope out potential medication mixing risks. It refers to the fact that if consume grapefruit along with a particular drug, you are likely to have a higher concentration of that drug in the body. Grapefruit drug interactions work the same way as CBD, which means that they too interfere with the CYPs enzymes to raise the levels of certain drugs. So the grapefruit rule implies that you should consider any grapefruit warning that you find on a drug to serve twofold as a CBD warning. Please note that this is a general rule of thumb and does not account for all possible scenarios.
According to the FDA, drugs such as steroids and corticosteroids (budesonide sold as Uceris and Entocort UC), heart rhythm medications (amiodarone sold as Nexterone and Pacerone, organ transplant rejection drugs (cyclosporine sold as Neoral and Sandimmune), and some antihistamines (fexofenadine sold as Allegra) are all on the grapefruit warning spectrum.
Other Drugs Affected by CBD
Other drugs that are prone to CBD interactions include stimulants such as Adderall (which causes a decrease in appetite), as well as heartburn drugs like Prilosec (interactions can cause diarrhea), and diabetes drugs like metformin (can also cause diarrhea). Also, drugs such as bronchodilators, antidepressants, antipsychotics, antihistamines (Benadryl), some NSAIDs (Advil and Aleve), and certain antibiotics (clarithromycin and erythromycin) may also be prone to CBD drug interactions.
The above list of CBD drug interactions is not exhaustive—there are many other medications that should not be mixed with CBD. Again, it is always best to have a candid conversation with your doctor about your CBD use.
The Bottom Line
While CBD generally comes with mild or non-existent adverse effects when taken on its own, it has the ability to affect certain medications when ingested in tandem. Also, many CBD products contain additives that come with their own distinct effects—so you should try your best to stick to pure CBD oil. While the grapefruit rule can help you stay clear of adverse interactions, it is always best to consult your doctor before incorporating CBD into your medicinal regimen, or when adopting a new medication as a CBD user.
Burstein, S. (2015). Cannabidiol (CBD) and its analogs: a review of their effects on inflammation. DOI: 10.1016/j.bmc.2015.01.059
Iannotti FA, et al. (2018). Effects of non-euphoric plant cannabinoids on muscle quality and performance of dystrophic mdx mice. DOI: 10.1111/bph.14460
Atalay S, et al. (2019). Antioxidative and anti-inflammatory properties of cannabidiol. DOI: 10.3390/antiox9010021.
Manzanares J, et al. (2006). Role of the cannabinoid system in pain control and therapeutic implications for the management of acute and chronic pain episodes. DOI: 10.2174/157015906778019527
Cannabidiol (CBD) Critical Review Report. (2018). https://www.who.int/medicines/access/controlled-substances/CannabidiolCriticalReview.pdf
Taylor, L. (2018). A phase I, randomized, double-blind, placebo-controlled, single ascending dose, multiple dose, and food effect trial of the safety, tolerability, and pharmacokinetics of highly purified cannabidiol in healthy subjects. DOI: 10.1007/s40263-018-0578-5
Brown, JD. (2019). Potential adverse drug events and drug-drug interactions with medical and consumer cannabidiol (CBD) use. DOI: https://doi.org/10.3390/jcm8070989
Pavlovic R, et al. (2018). Quality traits of “cannabidiol oils”: cannabinoids content, terpene fingerprint and oxidation stability of European commercially available preparations. DOI: 10.3390/molecules23051230
Ronen A, et al. (2008). Effects of THC on driving performance, physiological state and subjective feelings relative to alcohol. DOI: https://doi.org/10.1016/j.aap.2007.10.011
Liu Y, et al. (2015). Digestion of nucleic acid starts in the stomach. DOI: 10.1038/srep11936
Almazroo OA, et al. (2017). Drug metabolism in the liver. DOI: 10.1016/j.cld.2016.08.001
Remmer, MDH. (1970). The role of the liver in drug metabolism. DOI: 10.1016/S0002-9343(70)80129-2
Le, Jennifer. (2020). Drug metabolism. https://www.msdmanuals.com/home/drugs/administration-and-kinetics-of-drugs/drug-metabolism
Sweeney BP, et al. (2006). Liver enzyme induction and inhibition: implications for anesthesia. DOI: 10.1111/j.1365-2044.2005.04462.x
Zendulka O, et al. (2016). Cannabinoids and cytochrome P450 interactions. DOI: 10.2174/1389200217666151210142051
Mannila J, et al. (2007). Precipitation complexation method produces cannabidiol/B-cyclodextrin inclusion complex suitable for sublingual administration of cannabidiol. DOI: 10.2174/1389200217666151210142051
Ewing LE, et al. (2019). Hepatotoxicity of a cannabidiol-rich cannabis extract in the mouse model. DOI: 10.3390/molecules24091694
Pan H, et al. (2009). Cannabidiol attenuates cisplatin-induced nephrotoxicity by decreasing oxidative/nitrosative stress, inflammation, and cell death. DOI: 10.1124/jpet.108.147181
Zuardi AW, et al. (1995). Antipsychotic effect of cannabidiol: 30 years of a translational investigation. DOI: 10.2174/138161212802884681
Shader RI, et al. (1993). Use of benzodiazepines in anxiety disorders. DOI: 10.1056/NEJM199305133281907
Bykov, Katsiaryna. (2021). CBD and other medications: proceed with caution. https://www.health.harvard.edu/blog/cbd-and-other-medications-proceed-with-caution
Kocis PT, et al. (2020). Delta-9-tetrahydrocannabinol and cannabidiol drug-drug interactions. DOI: 10.1159/000507998
NTI meds to be closely monitored when co-administered with cannabinoids. (2020). https://sites.psu.edu/cannabinoid/files/2020/06/NTI-Meds-to-be-Closely-Monitored-when-Co-Administered-with-Cannabinoids_2020_04_25.pdf
Ng YT, et al. (2007). Clobazam. DOI: 10.1016/j.nurt.2006.11.002.
Lattanzi S, et al. (2020). Cannabidiol efficacy and clobazam status: a systematic review and meta-analysis. DOI: 10.1111/epi.16546.
Balachandran P, et al. (2021). Cannabidiol interactions with medications, illicit substances, and alcohol: a comprehensive review. DOI: 10.1007/s11606-020-06504-8.
Chesak, J. (2019). CBD and drug interactions: what you need to know. https://www.healthline.com/health/cbd-and-drug-interactions-what-you-need-to-know
Grapefruit juice and some drugs don’t mix: grapefruit juice can affect how well some medicines work, and it may cause dangerous side effects. (2017). https://www.fda.gov/consumers/consumer-updates/grapefruit-juice-and-some-drugs-dont-mix