CBD and the Cytochrome P450 Enzyme System: What You Need to Know About Drug Interactions

by | Sep 18, 2025 | Health, Herbs, Supplements | 0 comments

Cannabidiol (CBD) has gained popularity for its potential therapeutic benefits that range from reducing anxiety and inflammation to improving sleep quality. However, CBD is not metabolized in isolation. Like many other compounds, it interacts with the liver’s Cytochrome P450 (CYP450) enzyme system, a family of enzymes responsible for breaking down the majority of pharmaceutical drugs.

Understanding how CBD influences these enzymes is crucial, because it may increase or decrease the levels of certain medications in the body, potentially leading to unwanted side effects or reduced effectiveness. Be sure to read further below if you take any medications and currently use CBD as a part of your wellness routine.

The Cytochrome P450 System and CBD

  • CYP450 enzymes are responsible for metabolizing about 60–70% of prescription medications.
  • CBD can inhibit or compete with certain CYP450 enzymes, particularly CYP3A4 and CYP2C19.
  • This inhibition can slow down drug metabolism, leading to higher concentrations of medications in the bloodstream.
  • Conversely, in some cases CBD may induce enzymes, accelerating metabolism and lowering drug effectiveness.

Medication Classes Affected by CBD Through CYP450

Here’s how the major drug classes known below may be affected when taken alongside CBD:

1. Proton-Pump Inhibitors (PPIs)

Medications: omeprazole, esomeprazole, pantoprazole

  • Metabolized by CYP2C19 and CYP3A4.
  • CBD may increase blood levels of PPIs, possibly worsening side effects like headache, diarrhea, or nutrient malabsorption.

2. Oral Hypoglycemic Agents (for diabetes)

Medications: metformin, pioglitazone, repaglinide

  • Many are metabolized by CYP2C8 and CYP3A4.
  • CBD may alter their metabolism, risking hypoglycemia or reduced glucose control.

3. Anesthetics

Medications: propofol, ketamine, midazolam

  • Primarily metabolized by CYP3A4 and CYP2B6.
  • CBD may prolong sedation or increase anesthetic depth, important during surgery.

4. Sulfonylureas (another diabetes class)

Medications: glipizide, glyburide

  • Metabolized by CYP2C9.
  • CBD’s inhibition may raise sulfonylurea levels, leading to dangerous hypoglycemia.

5. HMG-CoA Reductase Inhibitors (Statins)

Medications: simvastatin, atorvastatin, lovastatin

  • Metabolized by CYP3A4.
  • CBD may elevate statin levels, increasing risk of muscle pain, liver toxicity, or rhabdomyolysis.

6. Antihistamines

Medications: loratadine, diphenhydramine, cetirizine

  • Some processed by CYP3A4 and CYP2D6.
  • CBD may cause stronger sedation or dry mouth.

7. Calcium Channel Blockers

Medications: amlodipine, verapamil, diltiazem

  • Heavily metabolized by CYP3A4.
  • CBD may enhance their effects, increasing risk of low blood pressure or dizziness.

8. Beta-Blockers

Medications: propranolol, metoprolol

  • Metabolized by CYP2D6.
  • CBD could amplify their effects, causing bradycardia or low blood pressure.

9. Prokinetics

Medications: metoclopramide, domperidone

  • Involve CYP3A4 metabolism.
  • CBD may raise levels, increasing risk of extrapyramidal symptoms (involuntary movements).

10. Immune Modulators

Medications: cyclosporine, tacrolimus

  • Metabolized by CYP3A4.
  • CBD may elevate drug concentrations, risking toxicity or organ rejection complications.

11. Benzodiazepines

Medications: diazepam, alprazolam, lorazepam

  • CYP3A4 and CYP2C19 are key enzymes.
  • CBD may prolong sedation, drowsiness, and cognitive impairment.

12. Antidepressants

Medications: SSRIs (sertraline, fluoxetine), TCAs (amitriptyline), SNRIs (venlafaxine)

  • Metabolized by CYP2D6, CYP3A4, and CYP2C19.
  • CBD may intensify effects, leading to serotonin syndrome or worsening side effects.

13. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Medications: ibuprofen, diclofenac, naproxen

  • Metabolized by CYP2C9 and CYP3A4.
  • CBD could raise drug levels, increasing risk of stomach irritation, ulcers, or kidney damage.

14. Analgesics (Pain Medications)

Medications: codeine, tramadol, acetaminophen, opioids

  • Metabolized by CYP2D6, CYP3A4.
  • CBD may increase sedation or respiratory depression risk when combined with opioids.

15. Antacids

Medications: aluminum hydroxide, magnesium hydroxide

  • These do not directly use CYP450 but can affect absorption of CBD and other drugs by altering stomach acidity.

Key Takeaways

  • CBD and the CYP450 system have a complex relationship: CBD can inhibit or compete for enzyme activity, slowing down or altering the metabolism of many drugs.
  • This can lead to higher blood concentrations of medications, stronger side effects, or in some cases reduced drug effectiveness.
  • People taking statins, blood pressure medications, benzodiazepines, antidepressants, or diabetes drugs should be especially cautious.
  • Always consult a healthcare provider before mixing CBD with prescription medications. Doctors may need to adjust dosages or monitor blood levels.

CBD is nonintoxicating as it does not demonstrate psychoactive activity. However, it exerts several beneficial pharmacological effects. The compound has analgesic and anti-inflammatory activities mediated by inhibiting cyclooxygenase and lipoxygenase. This anti-inflammatory action is several hundred times more potent than acetylsalicylic acid. Furthermore, cannabidiol inhibits the synthesis of leukotriene TXB4 in polymorphonuclear cells.[1] Several investigations have confirmed CBD’s anxiolytic, antiemetic, antipsychotic, and neuroprotective antioxidant properties.[2][3]

The Bottom Line: 

CBD can be beneficial, but because it interacts with the same liver enzymes that metabolize many common medications, it is essential to approach CBD use with professional medical guidance. It is especially important to check with a medical professional if you’re taking prescription drugs that rely on the CYP450 enzyme system. Additionally, understanding CBD’s pharmacology helps healthcare professionals to tailor treatment plans to individual patient needs. Enhancing patient care and optimizing outcomes in epilepsy, neuropathic pain, and anxiety disorders requires emphasis on the critical role of the interprofessional healthcare team in overseeing CBD therapy.  Be sure to read more into the references and resources included below.

References:

  1. Alsherbiny MA, Li CG. Medicinal Cannabis-Potential Drug Interactions. Medicines (Basel). 2018 Dec 23;6(1):3. doi: 10.3390/medicines6010003. PMID: 30583596; PMCID: PMC6473892.
  2. Antoniou T, Bodkin J, Ho JM. Drug interactions with cannabinoids. CMAJ. 2020 Mar 2;192(9):E206. doi: 10.1503/cmaj.191097. PMID: 32122975; PMCID: PMC7055953.
  3. Balachandran P, Elsohly M, Hill KP. Cannabidiol Interactions with Medications, Illicit Substances, and Alcohol: a Comprehensive Review. J Gen Intern Med. 2021 Jul;36(7):2074-2084. doi: 10.1007/s11606-020-06504-8. Epub 2021 Jan 29. PMID: 33515191; PMCID: PMC8298645.
  4. Brown JD. Potential Adverse Drug Events with Tetrahydrocannabinol (THC) Due to Drug-Drug Interactions. J Clin Med. 2020 Mar 27;9(4):919. doi: 10.3390/jcm9040919. PMID: 32230864; PMCID: PMC7231229.
  5. Chapin MR, Kane-Gill SL, Li X, Abanyie K, Taneja SB, Egbert S, Paine MF, Boyce RD. Part 2: Drug Interactions Involving Cannabis Products in Persons Aged 18 and Over: A Summary of Published Case Reports and Analysis of the FDA Adverse Event Reporting System. Pharmacol Res Perspect. 2025 Feb;13(1):e70047. doi: 10.1002/prp2.70047. PMID: 39719832; PMCID: PMC11668913.
  6. Downs G, Greer R, Moses G, Gurgenci T, Good P, Hardy J. Drug Interactions in People on Cannabidiol: Is There Cause for Concern? Cannabis Cannabinoid Res. 2024 Nov 14. doi: 10.1089/can.2024.0041. Epub ahead of print. PMID: 39539239.
  7. Gaston TE, Bebin EM, Cutter GR, Grayson L, Szaflarski JP. Final analysis of potential drug-drug interactions between highly purified cannabidiol and anti-seizure medications in an open-label expanded access program. Epilepsia Open. 2023 Dec;8(4):1405-1412. doi: 10.1002/epi4.12815. Epub 2023 Aug 26. PMID: 37593907; PMCID: PMC10690661.
  8. Ho JJY, Goh C, Leong CSA, Ng KY, Bakhtiar A. Evaluation of potential drug-drug interactions with medical cannabis. Clin Transl Sci. 2024 May;17(5):e13812. doi: 10.1111/cts.13812. PMID: 38720531; PMCID: PMC11079547.
  9. Huestis MA, Solimini R, Pichini S, Pacifici R, Carlier J, Busardò FP. Cannabidiol Adverse Effects and Toxicity. Curr Neuropharmacol. 2019;17(10):974-989. doi: 10.2174/1570159X17666190603171901. PMID: 31161980; PMCID: PMC7052834.
  10. Meissner H, Cascella M. Cannabidiol (CBD) in Clinical Care. [Updated 2024 May 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556048/
  11. Ng T, Gupta V, Keshock MC. Tetrahydrocannabinol (THC) [Updated 2023 Nov 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK563174/