What Medications Should Not Be Taken With CBD - Glow Bar London

September 28, 2022 5 min read

What Medications Should Not Be Taken with CBD?

Most CBD manufacturers advertise CBD products as supplements. Since there is no medical prescription for most CBD products, how can one be careful when under other medications? This article looks into how CBD interacts with the body and other medications. It also outlines medications one needs to avoid when using CBD.

Many people use CBD as a supplement to help them with different conditions. CBD can be used daily or when needed. Since most people use CBD to help with long-term conditions, they might already be under other medications before. Though research has shown that CBD is safe to use, it can interact with other medications in the body because it is a natural compound. This combination might cause a positive or negative reaction. Most companies advise their customers to consult a physician using CBD when under other prescriptions. This article looks into which medications should not be taken with CBD.

How CBD Works in the Body

Cannabidiol, commonly known as CBD, is one of the compounds found in the cannabis plant. CBD is mainly used for several conditions because of its potential therapeutic benefits. It is the preferred compound because it does not make one high and is effective without showing dangerous side effects. CBD works with the endocannabinoid system in the human body, responsible for maintaining biological balance (homeostasis). CBD is widely used to help with stress, anxiety, sleep, and insomnia. Kis et al. (2019) pointed out that CBD can help with several neurodegenerative conditions and reduce cancer treatment side effects. Besides the medical benefits, CBD is also used as a supplement. However, it interacts with different systems in the body.

CBD and Drug Metabolism

Metabolism refers to how supplements, food, and drugs are processed in the body. On the other hand, drug metabolism is the rate at which medications or supplements are broken down and the period in which they stay in one's system. Most metabolic processes occur in the gut and liver. CBD capsules, for instance, are absorbed through the liver. CBD gets into the digestive system, and the liver breaks it down into metabolites allowing circulation throughout the body. It is later excreted through feces and urine.

Cytochrome 450 System

Besides breaking down compounds into metabolites, the liver helps detoxify and eliminate foreign drugs and toxic compounds through the cytochrome P450 system. McDonnell & Dang (2013) pointed out that this system is made of particular enzymes that turn fat-soluble compounds into water-soluble ones to be absorbed into the body efficiently. The cytochrome P450 system is responsible for processing a high percentage of foreign substances consumed. However, certain substances interfere with the cytochrome P450 system processes medications, making them metabolize faster or lower than usual. CBD is one of the compounds that affect the cytochrome P450 system.

CBD and the Cytochrome P450 system

Jiang et al. (2013) showed that CBD binds to the site of the enzymatic activity in the Cytochrome P450 system. By becoming a competitive inhibitor, CBD prevents other compounds from being broken down. The inhibitory effect depends on the amount of CBD one has taken, the individual's metabolism rate, and the type of CBD product. High amounts of CBD can result in competitive blockage of the enzymatic activity. When taken with other drugs, CBD competes with them, getting metabolized fast. Chemicals that inhibit the Cytochrome system lead to deactivation of other drugs and prolonged presence in the body that can lead to high levels of the medications at a time. In turn, this can lead to adverse reactions in the immune system and an overdose.

Which Drugs Should Not Be Taken with CBD

Grapefruit should not be taken with some medications. If the doctor or drug is indicated not to be taken with grapefruit, it will likely be affected by CBD in the liver because it affects metabolism the same way CBD does. Taking grapes while on some medications can lead to a high concentration of the drugs in the bloodstream. According to Guttman et al. (2020), furanocoumarins, chemicals found in grapefruit,  act as inhibitors of the cytochrome P450 system, the same way CBD does.

Some of the drugs that use the Cytochrome P450 enzyme system and can be affected by the use of grapefruit and CBD include:

  • Steroids and corticosteroids
  • Antidepressants
  • Prokinetics
  • Antihistamines
  • HIV antivirals
  • Calcium channel blockers
  • Antibiotics
  • Anesthetics
  • Immune modulators
  • Antipsychotics
  • Anticonvulsants
  • Beta-blockers
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Precautions When Using CBD with Other Drugs


The liver metabolizes CBD and other medications. Therefore, one can take time between taking the drugs. Medications are excreted after some time. One can use this time to wait before taking CBD. However, one needs to talk to a health professional for advice before consuming other medications with CBD.

Type of CBD Product Used

CBD formulations interact differently in the human body. The topical application of CBD, for instance, concentrates on the receptors on the skin, limiting the amount of CBD in the bloodstream, and making it unlikely for the CBD to interfere with other medications. Sublingual and vaping methods are the fastest ways to get CBD into the bloodstream, making them run the chance of interacting with other medications.


CBD is safe since it does not cause one to feel high or have adverse side effects. However, as a natural compound that interacts with the body system, it can affect how the body metabolizes other medications. Though the Cytochrome P450 enzyme system allows CBD to be effective in the body with plenty of benefits, it is wise to seek professional advice on using CBD with other medications. If you are under other prescriptions and want to use CBD, speak to your doctor first for advice. A qualified physician will advise how to mix CBD with other drugs by reducing dosage or recommending the right way to use it. This will make you benefit from using CBD and avoid the effects of mixing CBD with other medications.


Guttman, Y., Yedidia, I., Nudel, A., Zhmykhova, Y., Kerem, Z., & Carmi, N. (2020). New grapefruit cultivars exhibit low cytochrome P4503A4-Inhibition activity. Food and Chemical Toxicology, 137, 111135.

Jiang, R., Yamaori, S., Okamoto, Y., Yamamoto, I., & Watanabe, K. (2013). Cannabidiol is a potent inhibitor of the catalytic activity of cytochrome P450 2C19. Drug metabolism and pharmacokinetics, DMPK-12.

Kis, B., Ifrim, F. C., Buda, V., Avram, S., Pavel, I. Z., Antal, D., ... & Danciu, C. (2019). Cannabidiol—From plant to human body: A promising bioactive molecule with multi-target effects in cancer. International journal of molecular sciences, 20(23), 5905.

McDonnell, A. M., & Dang, C. H. (2013). Basic review of the cytochrome p450 system. Journal of the advanced practitioner in oncology, 4(4), 263.