What Drugs Should Not Be Taken with CBD?

4 Min Read

While CBD has gained popularity among individuals who are looking for relief, CBD products are not always the best option if you’re currently taking prescription drugs. The reason for this is because it could create potential interactions.

Potential CBD drug interactions

When talking about CBD drug interactions, MedlinePlus says that these can be broken down into two basic categories. [3] Those that could potentially create a dangerous interaction and, therefore, should never be taken with CBD, and those that simply require that you be cautious when combining the two.

The two drugs that should never be taken with CBD oils or other CBD dietary supplements are clobazam and valproic acid. Taking CBD with clobazam could intensify the way this drug works, increasing its side effects too. Further, combining valproic acid with CBD could cause injury to your liver.

The second category of drugs is those which require using some caution when taking them with CBD. Prescriptions may fall into this class because they either increase or decrease how quickly your liver enzymes are able to break down the drugs, thus either reducing or intensifying their effects.

As you will see, many of these are cytochrome P450 enzymes, or CYP450s for short. Therefore, if you’re taking any prescription drug falling into the CYP450 enzymes category, it’s best to consult with a medical professional before starting a CBD regimen.

These drugs include:

  • CYP1A1 substrates (muscle relaxers and bronchodilators)
    • examples include: Lorzone and Theo-Dur
  • CYP1A2 substrates (antidepressants, antipsychotics, chemotherapy nausea drugs, beta-blockers, and calcium channel blockers)
    • examples include: Elavil, Haldol, Zofran, Inderal, Calan, and Isoptin
  • CYP1B1 substrates (proton pump inhibitors, antipsychotics, digestive system treatment drugs, and cancer medicines)
    • examples include: Prilosec, Clozaril, Prevacid, Eloxatin, and Tarceva
  • CYP2A6 substrates (sedatives, pain relievers, general anesthetics, antiepileptics, and medicines that block the body’s ability to metabolize alcohol)
    • examples include: Heminevrin, Penthrox, Fluothane, Depacon, and Antabuse
  • CYP2B6 substrates (anesthesia, epilepsy drugs, muscle relaxers, barbiturates, and corticosteroids)
    • examples include: Ketalar, Phenobarbital, Norflex, Seconal, and Decadron
  • CYP2C19 substrates (stomach acid drugs, proton pump inhibitors, benzodiazepines, pain relievers, and antivirals)
    • examples include: Prilosec, Prevacid, Protonix, Valium, Soma, and Viracept
  • CYP2C8 substrates (antiarrhythmics, anticonvulsants, antimalarial, nonsteroidal anti-inflammatories, anti-cancer drugs, and diabetes drugs)
    • examples include: Cordarone, Tegretol, Aralen, Voltaren, Taxol, and Prandin
  • CYP2C9 substrates (anti-inflammatories, ibuprofen, antidepressants, blood thinners, diabetes drugs, and hypertension meds)
    • examples include: Cataflam, Voltaren, Motrin, Mobic, Feldene, Celebrex, Elavil, Coumadin, Glucotrol, and Cozaar
  • CYP2D6 substrates (antidepressants, antiarrhythmics, antipsychotics, chemotherapy nausea drugs, selective serotonin reuptake inhibitors, and pain relievers)
    • examples include: Elavil, Norpramin, Tambocor, Haldol, Zofran, Paxil, Risperdal, Ultram, and Effexor
  • CYP3A4 substrates (benzodiazepines, calcium channel blocker, antibiotics, cholesterol meds, antihistamines, triazolobenzodiazepines, and antifungals)
    • examples include: Xanax, Norvasc, Biaxin, Mevacor, Allegra, Halcion, and Nizoral
  • CYP3A5 substrates (testosterone, progesterone, calcium channel blockers, and organ rejection meds)
    • examples include: Endometrin, Prometrium, Adalat CC, and Sandimmune)
  • CYP2C19 inhibitors (histamine receptor antagonists, selective serotonin reuptake inhibitors, stomach acid reducers, platelet blocking drugs, and seizure medications)
    • examples include: Tagamet, Luvox, Prilosec, Ticlid, and Topamax)
  • CYP3A4 inhibitors (antiarrhythmics, calcium channel blockers, antibiotics, and protease inhibitors)
    • examples include: Cordarone, Cardizem, Erythrocin, Crixivan, Fortovase, and Norvir)
  • CYP3A4 inducers (anticonvulsants, antiepileptic drugs, and antibiotics)
    • examples include: Tegretol, Dilantin, Mocobutin, and Rifampin
  • CYP2C19 inducers (anticonvulsants, corticosteroids, and antibiotics)
    • examples include: Tegretol, Deltasone, and Rimactane
  • Glucuronidated drugs (acetaminophen, benzodiazepines, analgesics, and antiretrovirals)
    • examples include: Tylenol, Serax, Haldol, Lamictal, Roxanol, and Retrovir)
  • Central nervous system depressants (benzodiazepines, pentobarbital, phenobarbital, fentanyl, morphine, and propofol)
    • examples include: Nembutal, Luminal, Seconal, Duragesic, and Diprivan
  • Anticonvulsants and anti-seizure meds
    • examples include: Eslicarbezepine, Rufinamide, Topiramate, and Zonisamide

The grapefruit juice test

Looking at this list can be more than a little overwhelming. However, there is a simpler way to help identify whether CBD could potentially interact with your prescription medication. It involves asking whether or not it is safe to drink grapefruit juice.

Harvard Medical School indicates that “CBD can increase the level in your blood of the blood thinner coumadin, and it can raise levels of certain other medications in your blood by the exact same mechanism that grapefruit does.” [4]

By default then, if you are unable to drink grapefruit juice while taking your prescription medication, it may be unsafe to take CBD as well.

The final word

In the end, if you currently take any prescription medications, it’s best to consult with your healthcare provider before taking CBD oil.

In addition to helping you decide whether the CBD is safe to take, this medical professional can also provide medical advice regarding the dose of CBD that will be effective without causing any adverse effects.

In some cases, this may involve starting with a low dose of CBD and only moving to high doses once you know it is safe to do so.




[1] Russo, E. “Cannabinoids in the Management of Difficult to Treat Pain.” Therapeutics and Clinical Risk Management. Feb 2008; 4(1): 245-259. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2503660/

[2] Elms, L et al. “Cannabidiol in the Treatment of Post-Traumatic Stress Disorder: A Case Series.” Journal of Alternative and Complementary Medicine. Apr 01, 2019; 25(4): 392-397. doi: 10.1089/acm.2018.0437. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6482919/

[3] “Cannabidiol (CBD).” MedlinePlus. Accessed Sep 18, 2019. https://medlineplus.gov/druginfo/natural/1439.html

[4] Grinspoon, P. “Cannabidiol (CBD) – What We Know and What We Don’t.” Harvard Health Publishing, Harvard Medical School. Aug 24, 2018. https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476