Cannabidiol (CBD)

Prescription CBD is used for treatment of certain seizure disorders.

Some people use CBD to treat many other health problems, including the following:

• Bipolar disorder

• Pain

• Anxiety

• Crohn disease

• Diabetes

• Sleep problems

• Multiple sclerosis

• Symptoms of withdrawal from heroin, morphine, and other opioidsSymptoms of withdrawal from heroin, morphine, and other opioids

Oral CBD has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of seizures associated with 2 epileptic encephalopathies: Lennox-Gastaut syndrome and Dravet syndrome. These epileptic encephalopathies start in childhood and involve frequent seizures along with severe impairments in cognitive development. Clinical studies have reported on the effectiveness of CBD in these patients and other patients with treatment-resistant epilepsies (2, 3). However, further research is needed to determine whether cannabinoids are effective for other, more prevalent forms of epilepsy.

There are limited data to suggest that CBD may have a modest benefit for neuropathic pain. A Cochrane systematic review on cannabis‐based medicines for chronic neuropathic pain in adults included 16 studies with 1750 participants (4). The analysis showed that cannabis‐based medications may increase the number of people achieving 50% or greater pain relief compared with placebo (21% versus 17%). Cannabis-based medications probably increase the number of people achieving pain relief of 30% or greater compared with placebo (39% versus 33%). The authors concluded that this small improvement in neuropathic pain might be outweighed by the potential harms.

An oromucosal spray has demonstrated some success for the treatment of spasticity in multiple sclerosis (5).

There are numerous clinical studies regarding the uses of CBD for various symptoms and disorders summarized on the National Institutes of Health (NIH) website.

CBD can have adverse effects such as dry mouth, low blood pressure, diarrhea, decreased appetite, mood changes, light-headedness, fatigue, rash, insomnia and poor quality sleep, and sleepiness. The Food and Drug Administration (FDA) strongly advises against CBD use during pregnancy (6).

CBD can cause increased transaminases and liver injury.

CBD is metabolized by the cytochrome p450 (CYP) enzymes CYP3A4 and CYP2C19. Coadministration with medications that are metabolized by or inhibit CYP3A4 or CYP2C19 can increase plasma concentrations of these medications or of CBD, which may result in increasing their effects and a greater risk of adverse reactions (7).

CBD may increase the serum concentration and effects of a number of medications, including the following:

• Antiseizure medications (eg, brivaracetam, carbamazepine, clobazam, topiramate)Antiseizure medications (eg, brivaracetam, carbamazepine, clobazam, topiramate)

• Immunosuppressants used to prevent rejection after an organ transplant (eg, cyclosporine, tacrolimus)Immunosuppressants used to prevent rejection after an organ transplant (eg, cyclosporine, tacrolimus)

• Anticoagulants (eg, warfarin)Anticoagulants (eg, warfarin)

• Tricyclic antidepressants

• Proton pump inhibitors (eg, omeprazole); diarrhea may occurProton pump inhibitors (eg, omeprazole); diarrhea may occur

• Nicotine, prolonging duration of action of nicotineNicotine, prolonging duration of action of nicotine

• Lithium, causing or increasing lithium toxicityLithium, causing or increasing lithium toxicity

• Ketamine, possibly enhancing antidepressant effectsKetamine, possibly enhancing antidepressant effects

• MethadoneMethadone

• LevothyroxineLevothyroxine

CBD can cause sleepiness and drowsiness, so taking both CBD and sedatives (eg, benzodiazepines, phenobarbital, morphine, alcohol) may make people too drowsy.CBD can cause sleepiness and drowsiness, so taking both CBD and sedatives (eg, benzodiazepines, phenobarbital, morphine, alcohol) may make people too drowsy.

Information on interactions is emerging. Any medication that has a narrow therapeutic index (eg, amiodarone) warrants caution and close monitoring with CBD use due to the possibility of drug interactions. Information on interactions is emerging. Any medication that has a narrow therapeutic index (eg, amiodarone) warrants caution and close monitoring with CBD use due to the possibility of drug interactions.

Because of the potential direct hepatotoxicity of CBD, increased hepatoxicity may occur when other hepatotoxic medications (eg, acetaminophen, valproic acid) are taken concurrently. Because of the potential direct hepatotoxicity of CBD, increased hepatoxicity may occur when other hepatotoxic medications (eg, acetaminophen, valproic acid) are taken concurrently.

A number of medications, including antiseizure medications and rifampin, may lower the serum concentration of CBD.A number of medications, including antiseizure medications and rifampin, may lower the serum concentration of CBD.

Tricyclic antidepressants may increase serum concentrations of CBD and thus may increase adverse effects of CBD.

(See also table Some Possible Dietary Supplement–Medication Interactions.)

1. 1. Bonn-Miller MO, Loflin MJE, Thomas BF, et al. Labeling accuracy of cannabidiol extracts sold online. . Labeling accuracy of cannabidiol extracts sold online.JAMA. 318(17):1708-1709, 2017. doi:10.1001/jama.2017.11909

2. 2. Szaflarski JP, Bebin EM, Comi AM, et al. Long-term safety and treatment effects of cannabidiol in children and adults with treatment-resistant epilepsies: Expanded access program results. . Long-term safety and treatment effects of cannabidiol in children and adults with treatment-resistant epilepsies: Expanded access program results.Epilepsia. 59(8):1540-1548, 2018. doi:10.1111/epi.14477

3. 3. Szaflarski JP, Bebin EM, Cutter G, et al. Cannabidiol improves frequency and severity of seizures and reduces adverse events in an open-label add-on prospective study. . Cannabidiol improves frequency and severity of seizures and reduces adverse events in an open-label add-on prospective study.Epilepsy Behav. 87:131-136, 2018. doi:10.1016/j.yebeh.2018.07.020

4. 4. Mucke M, Phillips T, Radbruch L, Petzke F, Hauser W. Cannabis-based medicines for chronic neuropathic pain in adults. Cochrane Database Syst Rev. 3(3):CD012182, 2018. Published 2018 Mar 7. doi:10.1002/14651858.CD012182.pub2

5. 5. Patti F, Messina S, Solaro C, et al; SA.FE. study group. Efficacy and safety of cannabinoid oromucosal spray for multiple sclerosis spasticity. J Neurol Neurosurg Psychiatry. 2016 Sep;87(9):944-51. doi: 10.1136/jnnp-2015-312591

6. 6. U.S. Food & Drug Administration. What You Should Know About Using Cannabis, Including CBD, When Pregnant or Breastfeeding. Accessed February 25, 2025.

7. 7. Balachandran P, Elsohly M, Hill KP. Cannabidiol interactions with medications, illicit substances, and alcohol: a comprehensive review. . Cannabidiol interactions with medications, illicit substances, and alcohol: a comprehensive review.J Gen Intern Med. 36(7):2074-2084, 2021. doi:10.1007/s11606-020-06504-8

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

1. National Institutes of Health (NIH), National Center for Complementary and Integrative Health: Cannabis (Marijuana) and Cannabinoids: What You Need To Know