What is the interaction between CBD and other medications? In recent years, numerous studies have confirmed the benefits of CBD (cannabidiol), a natural compound extracted from the Cannabis sativa plant, known for its relaxing, anti-inflammatory, and neuroprotective properties. Used in the form of oils, capsules, or creams, CBD is now employed as a support in various aspects of mental and physical health.
That said, if you’re already undergoing treatment with other medications, it’s essential to consult a doctor before starting CBD. The reason is simple: CBD may interact with some drugs, altering their effectiveness or, in some cases, increasing the risk of side effects. Understanding the mechanism behind these interactions is key to using cannabidiol safely and responsibly.
CBD and Drug Interactions: What to Know
CBD can interfere with the metabolism of several medications, affect their effectiveness, or increase the risk of side effects. These interactions primarily depend on liver enzymes, especially those in the cytochrome P450 family.
Groups of drugs with observed potential interactions include:
• Antiepileptics,
• Anticoagulants and antiplatelets,
• Psychotropic drugs (antidepressants, anxiolytics, antipsychotics),
• Antibiotics and antifungals,
• Cardiovascular drugs,
• Anti-inflammatories,
• Gastroprotective agents.
CBD and Medications: What Scientific Studies Say
Cannabidiol is primarily metabolized in the liver by enzymes of the cytochrome P450 family (CYP450), a system involved in processing many drugs.
According to some studies[1], CBD can inhibit or be affected by these enzymes, thereby altering the levels of other medications taken simultaneously. This can lead to either an increase or decrease in drug effectiveness, or a higher risk of side effects.
Interaction Between CBD and Antiepileptic Drugs
The interaction between CBD and antiepileptic drugs is among the most studied[2], particularly due to the development of Epidiolex, a CBD-based medication approved for certain rare forms of epilepsy.
CBD has been shown to increase plasma levels of some antiepileptics like clobazam, topiramate, rufinamide, and zonisamide, enhancing their effects, including sedative ones. In some cases, an increase in liver enzymes (ALT, AST) has also been noted when used with valproate, indicating possible liver strain.
Interaction Between CBD and Anticoagulants
One of the most clinically significant interactions is with warfarin[3], one of the most widely used anticoagulants. CBD can inhibit the CYP2C9 enzyme and slow down warfarin metabolism, leading to an increased INR, a measure of blood clotting time. Similar risks have been hypothesized for other antiplatelet drugs like clopidogrel, although clinical evidence remains limited.
Interaction Between CBD and Psychotropic Drugs
CBD can interfere with the metabolism of several psychotropic drugs[4], especially those that pass through the CYP2D6 and CYP3A4 enzymes. We are referring, in particular, to antidepressants such as fluoxetine, paroxetine and sertraline, anxiolytics such as diazepam, and antipsychotics such as risperidone and haloperidol. The main effect is a possible increase in the levels of these drugs in the blood, with a consequent higher incidence of side effects, such as sedation or motor disorders.
Interazione tra CBD e altri farmaci comuni
CBD may also interact with frequently used drugs such as:
• Omeprazole (a gastroprotector),
• Diclofenac (an anti-inflammatory),
• Amiodarone (an antiarrhythmic),
• Some antibiotics (clarithromycin, erythromycin),
• Certain antifungals and antivirals.
The effect can either be an enhancement or reduction in efficacy, depending on whether CBD acts as a metabolic inhibitor or inducer.
CBD Dosage and Monitoring with Other Medications
Using CBD oils alongside other medications doesn’t necessarily have to be avoided.
In many cases, it’s simply a matter of finding the correct dosage and maintaining careful medical monitoring, especially in the early stages of use.
It’s also worth noting that some medications can alter the metabolism of CBD or be affected by it. A helpful rule of thumb is the so-called “grapefruit effect”: if a drug’s leaflet advises against consuming grapefruit (which inhibits the same enzyme system involved in CBD metabolism), it’s likely that cannabidiol could also interfere. This is particularly true for antibiotics, antidepressants, beta-blockers, steroids, and antihistamines.
In all cases, it’s crucial to choose high-quality certified CBD products, such as those from Eusphera.
The Importance of Medical Advice
Taking CBD while undergoing other pharmacological treatments always requires prior consultation with a doctor.
Keep in mind that every individual has a unique metabolism, and interactions between medications and CBD can vary greatly from person to person. Seeking medical advice allows for an assessment of potential risks and benefits of CBD use, determination of appropriate dosage, and the setup of a proper monitoring plan.
[1] Cannabidiol Interactions with Medications, Illicit Substances, and Alcohol: a Comprehensive Review - Balachandran, Elsohly, Hill, 2021 (https://pmc.ncbi.nlm.nih.gov/articles/PMC8298645/)
[2] Interactions between cannabidiol and commonly used antiepileptic drugs - Gaston, Bebin, Cutter, Liu, Szaflarski, 2017 (https://pubmed.ncbi.nlm.nih.gov/28782097/)
[3] What to tell patients about CBD and blood thinners - G. Sison, 2023(https://www.singlecare.com/blog/cbd-and-blood-thinners)
[4] Drug–drug interactions as a result of co-administering Δ9-THC and CBD with other psychotropic agents - Carola Rong et al., Expert Opinion on Drug Safety, 2018 (https://www.researchgate.net/publication/320718588_Drug-Drug_Interactions_as_a_Result_of_Co-Administering_D_9_-THC_and_CBD_with_Other_Psychotropic_Agents)
