Drug interactions between CBD and medications are real. But should you be worried about them?
What drugs shouldn’t be taken with CBD – and when should you consult your doctor?
This article sheds new light on the topic of CBD-drug interactions based on the latest scientific research.
CBD has a vast influence on our health; it uses over 60 molecular targets to produce its effects on the body and brain, so it’s no wonder it competes with many ‘conventional’ medications (1).
Let’s start with the list of drugs that shouldn’t be taken with CBD oil.
Listing Drugs That You Shouldn’t Take With CBD
According to studies conducted by the Indiana University Department of Medicine, the following medications shouldn’t be taken with CBD due to the risk of negative interactions (2):
- Angiotensin II Blockers
- Anticonvulsants / Anti-Seizure Medications
- Calcium Channel Blockers
- HIV Antivirals
- HMG CoA Reductase Inhibitors (Statins)
- Immune Modulators
- Non-Steroidal Anti-Inflammatory Drugs
- Oral Hypoglycemic Agents
- Proton-Pump Inhibitors (PPIs)
- Steroids and Corticosteroids
There’s also a category of medications known as “prodrugs,” meaning they first need to be metabolized into their therapeutic molecules instead of being therapeutic on their own. In other words, the inactive compound is consumed, and once inside your body, it transforms into the active compound.
This mechanism relies heavily on the CYP450 system, so if the system gets disrupted by drug interaction, this can result in insufficient levels of the medication in the bloodstream – reducing its therapeutic potential.
CBD Interactions with Medications & Drugs
Here we elaborate on the most common interactions between CBD and pharmaceutical medications. If you take any of the substances listed below, talk to your doctor before ordering CBD oil.
CBD and Adderall Interaction
In a 2020 study, the authors found that small doses of medical cannabis reduced the use of ADHD medications in adults. CBD may interact with ADHD medications, decreasing their efficacy. The potential side effects of the interaction between CBD and Adderall may result in appetite fluctuations (3).
CBD and Antibiotics Interaction
Nobody has yet discovered interactions between CBD and antibiotics, although these interactions could happen if an antibiotic is processed through the CYP450 system. Some studies suggest that taking CBD together with antibiotics may potentiate the effects of the latter without any negative side effects. However, such suggestions come from preliminary research, so we need more clinical trials to confirm them (4).
CBD and Ibuprofen Interaction
Ibuprofen belongs to the class of drugs known as Non-Steroidal Anti-Inflammatory Drugs (NSAID). It can reduce inflammation and pain to some extent, just like CBD. Recently, there have been concerns from medical professionals about the potential negative interactions between CBD oil and Ibuprofen.
In a study published in The Journal of Neurology Research, the authors said there were no interactions between these two compounds, although this might depend on the dosage. If a high dosage of Ibuprofen and CBD is used, serious side effects may result (5).
CBD and Lamictal Interaction
Using CBD and Lamictal can increase the risk of side effects of the latter, such as confusion, poor focus, drowsiness, and impairment in judgment (for the elderly). Again, CBD can make Lamictal more or less effective, depending on the amount of both substances.
CBD and Lisinopril Interaction
Taking CBD can result in a temporary drop in blood pressure, so combining it with other medications for this condition might reduce it, even more, making you feel sleepy, dizzy, and confused. Talk to your doctor before buying CBD if you take Lisinopril.
CBD and Omeprazole Interaction
CBD can slow down the enzymes responsible for metabolizing omeprazole and other Proton Pump Inhibitors (PPIs). Taking CBD alongside certain heartburn medications can trigger diarrhea.
CBD and Prednisone Interaction
Since corticosteroids and CBD are potent inhibitors of the CYP450 enzyme system, simultaneous use may increase the risk of systemic adverse reactions to corticosteroid use due to impaired glucocorticoid clearance. Drugs like hydrocortisone and prednisolone should never be combined with CBD.
CBD and Thyroid Medications Interaction
Some people experience mild nausea when taking CBD oil with hyperthyroid medications. Both substances use the CYP450 enzyme system, so taking CBD with your meds may lead to increased activity of this gland.
Drug Metabolism: How Does CBD Interact With Other Drugs
There are two kinds of metabolism when it comes to human health. The first type refers to how your body uses energy for weight management; the second one covers the way drugs are metabolized in your body.
So, the first type is known as the basal metabolic rate, or in simple words, the number of calories a person needs to burn to maintain a healthy body weight.
The second is very different from the basal metabolic rates. Drug metabolism tells you how fast certain substances are processed and used by the body, with most of the processing happening in the liver.
Researchers call this phenomenon the ‘first-pass metabolism.’
Long story short, when you take a medication, a system of enzymes starts to break it down in the liver so that the body can use them for specific biological processes.
Similar to carbohydrates, fats, and proteins, which break down into sugars, lipids, and amino acids — medications break down into smaller particles.
From there, these molecules, known as metabolites, are used by the body and flushed with urine afterward.
How Exactly Is CBD Metabolized?
Drug metabolism tells you at what speed the body processes medications and how long their active compounds stay in your system.
When you take CBD oil, a capsule, or gummy, the active ingredient (CBD) needs to pass through the digestive system, where it gets released into the bloodstream.
The next step involves processing CBD in the liver, where it passes through the hepatic portal. The liver breaks CBD down into metabolites using its enzymes; after that time, CBD can circulate throughout the body and work its effects.
Understanding Cytochrome P450 System
On top of transforming drugs into metabolites, the liver also helps detoxify and flush foreign substances or toxic materials from the body. This can be done through a system of specialized enzymes called Cytochrome P450 (CYP450). With heme as a cofactor, these enzymes convert cannabinoids into more water-soluble compounds, increasing their absorption rate and effectiveness.
According to various estimates, around 70% of pharmaceutical drugs are metabolized by CYP450. Doctors and pharmacists use these enzymes to understand, assess, and predict the benefits of the drug and its side effects based on different doses.
However, CYP450 can be compromised by certain compounds that inhibit its activity — therefore disrupting the metabolism of drugs.
CBD is one of them.
How Does CBD Interact with the Cytochrome P450 System
As previously mentioned, CBD is an inhibitor of CYP450. Preclinical studies indicate that CBD binds to the site where the enzyme activity is the highest, competing with other compounds and thus blocking this system from breaking down other medications.
The inhibitory actions of CBD on the CYP450 enzymes depend on the dose of CBD, the user’s unique body chemistry, and the type of CBD they’re taking (e.g. full-spectrum CBD, broad-spectrum CBD or isolate). The higher the dose, the stronger CBD’s affinity to the active site of the metabolic enzymes – and with a stronger bond comes a more competitive effect.
When You Shouldn’t Take CBD with Medications
CBD isn’t a biologically inert substance — and you can tell it by looking at the scale of its health benefits.
Just like with many other medications, the pharmacodynamics and pharmacokinetics of CBD are complex, which makes it more understandable that it can interfere with the metabolism of certain drugs.
Any therapeutic compound that uses the CYP450 system can be potentially compromised by the inhibitory effects of CBD. Interestingly, this system is also inhibited by grapefruit juice, so if your medication has a grapefruit warning on it, it’s an indicator of potential drug interactions with CBD.
That being said, it’s not an official point of reference, so if you’re looking for professional medical advice, check in with your doctor and pharmacist before adding CBD to your medicating plan.
Always Ask Your Doctor First
In the above sections, we’ve just outlined the most common interactions between CBD and pharmaceutical drugs. The list of such drugs is longer, but that doesn’t mean that all pharmaceutical substances interact with CBD (e.g. ibuprofen and antibiotics).
Talking to a doctor experienced in cannabis and CBD use is a good idea if you want to establish the proper dosage and routine for both CBD and your medications. This way, you can avoid negative interactions; and since cannabidiol may work synergistically with some compounds, asking your doctor for advice can help you get the most out of both treatments.
A Final Note on CBD Drug Interactions
CBD has a well-established safety profile. Even major health agencies, such as the World Health Organization (WHO) recognize its therapeutic potential, adding that CBD is well tolerated by animals and humans, and doesn’t give dangerous side effects on its own.
However, CBD also has a significant impact on a range of systems, so if you take it alongside other medications, these compounds may interact with one another — not necessarily in a way you’d like them to interact.
CBD can either increase or decrease the concentrations of certain medications, depending on the dosage and the type of interaction. This means that you can either feel no relief or experience drug toxicity from your medication.
Although no such toxic interactions have been observed in CBD users, it’s important to consult your doctor to minimize the risk of unwanted events. It’s a more accurate way of weighing risks and benefits than trying to figure out these interactions yourself.
- de Almeida, D. L., & Devi, L. A. (2020). Diversity of molecular targets and signaling pathways for CBD. Pharmacology research & perspectives, 8(6), e00682. 
- Indiana University School of Medicine. (2020). Drug Interactions. Department of Medicine Clinical Pharmacology. 
- Khan, R., Naveed, S., Mian, N. et al. The therapeutic role of Cannabidiol in mental health: a systematic review. J Cannabis Res 2, 2 (2020). 
- Wassmann, C.S., Højrup, P. & Klitgaard, J.K. Cannabidiol is an effective helper compound in combination with bacitracin to kill Gram-positive bacteria. Sci Rep 10, 4112 (2020). 
- Emig, M., Kafaje, J., Ong, S. & Li, X. (2020). Cannabidiol and Non-Steroid Anti-Inflammatory Drug Interactions. Journal of Neurology Research, 10(4), 132–135.