CBD and Blood Pressure Medication: Interactions and Evidence

CBD can interact with some blood pressure medicines in two ways: it slows liver enzymes (CYP3A4, CYP2C19 and CYP2C9) that clear many heart drugs, and at high doses it can lower blood pressure by a few points on its own. Most of the risk is predicted rather than proven, and it rises with dose. Warfarin is the best-documented problem.

No trial has measured what happens when someone on amlodipine, metoprolol, lisinopril or losartan starts a retail CBD product. The evidence is a prescription drug label, enzyme studies, a few small blood pressure trials and case reports, almost all involving warfarin.

This guide sorts that evidence by drug class, explains why dose matters, and ends with questions to take to a pharmacist.

At a glance: CBD and blood pressure medication by drug class

Drug class (examples)	Main clearance route	Possible CBD effect	Evidence level
Calcium-channel blockers (amlodipine)	CYP3A4¹	Higher drug levels; more low blood pressure or ankle swelling	Theoretical. CBD mildly inhibited a CYP3A probe in people²
Beta-blockers (metoprolol)	Mainly CYP2D6³	Little metabolic effect expected; possible additive blood pressure lowering	Low concern. CBD did not inhibit a CYP2D6 probe²
ACE inhibitors (lisinopril)	Not metabolised; excreted unchanged⁴	Enzyme interaction unlikely; possible additive effect	Limited trial data, no signal reported⁵
ARBs (losartan)	CYP2C9 and CYP3A4 form active metabolite⁶	Altered ratio of parent drug to active metabolite	Pharmacokinetic data only; losartan exposure rose 77%²
Warfarin	S-warfarin mainly CYP2C9⁷	Rising INR, bleeding risk	Case reports, mostly at high doses⁸
Clopidogrel	Needs CYP2C19 to activate⁹	Possibly weaker antiplatelet effect	Theoretical; no CBD study found
Statins (simvastatin, atorvastatin)	CYP3A4¹⁰	Higher statin levels	Theoretical

How CBD drug interactions happen: the liver enzyme problem

The FDA label for Epidiolex, the only FDA-approved CBD medicine, states that cannabidiol is broken down mainly in the liver by CYP2C19 and CYP3A4, along with several UGT enzymes.¹¹ The same label warns that CBD raises levels of sensitive CYP2C19 substrates, predicts clinically significant interactions with CYP2C8 and CYP2C9 substrates, and advises considering dose reductions for affected drugs.¹¹ Laboratory work has shown CBD competitively inhibiting CYP3A4 and CYP2C9, among other enzymes.¹²

The clearest human data come from a 2023 crossover study in 18 healthy adults. Participants ate a brownie containing 640 mg CBD plus 20 mg THC, then took a cocktail of probe drugs, each cleared by a single enzyme. Compared with placebo, exposure to omeprazole (a CYP2C19 probe) rose 207%, losartan (CYP2C9) 77%, midazolam (CYP3A) 56% and caffeine (CYP1A2) 39%. Dextromethorphan, a CYP2D6 probe, was unaffected. A THC-only brownie inhibited none of the enzymes.²

For context, the FDA classes an inhibitor as moderate when it raises a sensitive probe’s exposure at least two-fold and strong at five-fold or more.¹³ On that scale, a single 640 mg CBD dose acted like a moderate CYP2C19 inhibitor and a weaker CYP3A and CYP2C9 inhibitor.

Lower, repeated doses still register. In a 2026 FDA-run study, 20 healthy adults took 2.5 mg/kg of CBD twice daily (about 350 mg a day for a 70 kg adult) for 12 days; exposure to the antidepressant citalopram rose 43%.¹⁴ The same pattern of enzyme overlap is why CBD shows up alongside kratom in pharmacist interaction checks, as covered in our guide to kratom and drug interactions.

Does CBD lower blood pressure on its own?

Modestly, at high doses, in small trials. An extra drop on top of medication is a separate risk from enzyme effects.

Single 600 mg dose. In a 2017 crossover trial in nine healthy young men, one 600 mg dose lowered resting systolic pressure by about 6 mmHg compared with placebo and blunted the rise during cold and mental-arithmetic stress tests. Heart rate went up and stroke volume fell.¹⁵
Seven days at 600 mg. A follow-up in 26 healthy men found a small fall in mean arterial pressure on day one, but no difference in resting pressure after a week, which the authors read as tolerance. Pressure during a handgrip stress test stayed about 6 mmHg lower.¹⁶
Untreated hypertension. A 2023 pilot crossover study in 16 adults gave 150 mg CBD every eight hours for 24 hours; 24-hour systolic pressure averaged about 5 mmHg lower than placebo.¹⁷
Five weeks in hypertension. The HYPER-H21-4 trial randomised 70 people with mild or moderate hypertension to 225 to 450 mg a day of a modified-release CBD or placebo. Average 24-hour systolic pressure fell by about 4.8 mmHg after 2.5 weeks and did not fall further when the dose was raised.⁵

These are small studies using doses many times a typical retail serving, and HYPER-H21-4 was sponsored by the maker of the formulation it tested. An additive effect is plausible; CBD is not shown to treat high blood pressure.

Calcium-channel blockers, beta-blockers, ACE inhibitors and ARBs: what is known and what is theoretical

Calcium-channel blockers

Amlodipine’s prescribing information says moderate and strong CYP3A inhibitors increase amlodipine exposure, may require a dose reduction, and warrants monitoring for low blood pressure and oedema.¹ CBD’s effect on the CYP3A probe in the 2023 study was below the FDA’s moderate threshold,² so a large effect at retail doses seems unlikely. Still, the combination stacks a possible rise in drug levels on CBD’s own blood pressure effect. No study has measured it directly.

Beta-blockers

Metoprolol is cleared mainly by CYP2D6,³ the one enzyme CBD did not inhibit in the probe study.² A metabolic interaction is therefore not expected. The open question is pharmacodynamic: CBD nudged heart rate up and blood pressure down in the 600 mg trial,¹⁵ and nobody has studied that alongside beta-blockade.

ACE inhibitors

Lisinopril is not metabolised at all and leaves the body unchanged in the urine,⁴ so the enzyme pathway does not apply. This class also has the most direct reassurance: in HYPER-H21-4, 32 of the participants were already on treatment, all with an ACE inhibitor alone or combined with a calcium-channel blocker or thiazide, and the authors reported no drug interactions with standard therapy over five weeks.⁵ That is one small trial, not proof of safety for everyone.

ARBs

Losartan is an unusual case because it is converted into a more active metabolite. Its label reports that fluconazole, a CYP2C9 inhibitor, raised losartan exposure by about 70% while cutting active metabolite exposure by about 40%.⁶ CBD raised losartan exposure by a similar 77% in the probe study,² which hints at the same shift, but the blood pressure consequence has not been measured.

CBD and blood thinners: warfarin, clopidogrel and newer anticoagulants

Warfarin

Warfarin is the strongest interaction signal. The more active S-form is cleared mainly by CYP2C9.⁷ In a 2018 case report, a 44-year-old man with a mechanical heart valve was stable on warfarin with an INR of 2.22. As prescription CBD was titrated up, his INR climbed to 6.86 at 10 mg/kg/day, about 1,050 mg a day, and his warfarin dose was eventually cut by about 30%. He had no bleeding.⁷ A second report described a man who needed nearly 20% less warfarin after starting Epidiolex.¹⁸

A 2023 systematic review found seven case reports of cannabinoid-anticoagulant interactions, all involving warfarin. Six showed INR rises, one involved bleeding, and the CBD doses were either above 600 mg a day or unknown. The authors rated the evidence very low quality but said clinicians should recognise the possibility.⁸ At the other end, an 85-year-old man taking about 5 mg of CBD a day from a dispensary oil showed no meaningful INR change over a year.¹⁹

Clopidogrel

Clopidogrel is a prodrug that relies on CYP2C19. Its label carries a boxed warning for people who are poor CYP2C19 metabolisers and advises avoiding omeprazole, a CYP2C19 inhibitor.⁹ CBD inhibited CYP2C19 more than any other enzyme in the probe study,² so a weaker antiplatelet effect is biologically plausible. We found no study testing it.

Newer anticoagulants

For apixaban, rivaroxaban and similar drugs, the 2023 review found no evidence of an interaction with cannabinoids,⁸ which reflects a lack of study rather than proven safety.

Statins and other heart medicines

Simvastatin, and to a lesser extent atorvastatin, are cleared by CYP3A4; pravastatin, rosuvastatin and fluvastatin are not significantly metabolised by it.¹⁰ The amlodipine label even caps simvastatin at 20 mg a day for people on amlodipine.¹ Any CBD effect on statins is theoretical, but the same enzyme logic applies.

The “grapefruit warning” rule of thumb

Pharmacists sometimes suggest a quick screen: if a medicine carries a grapefruit warning, ask about CBD too. Writing for the National Community Pharmacists Association, two pharmacists framed the question exactly this way, noting the overlap in enzymes and arguing that dose is the most important factor.²⁰

The heuristic is useful but incomplete. The FDA explains that grapefruit juice blocks intestinal CYP3A4 and lists statins and blood pressure drugs such as nifedipine among the affected medicines.²¹ CBD’s strongest effects in people, however, were on CYP2C19 and CYP2C9.² Warfarin and clopidogrel risks run through those enzymes, so a missing grapefruit warning on the box does not mean CBD is irrelevant.

Dose relevance: Epidiolex doses versus retail CBD

Most interaction data come from doses far above what consumers take. Epidiolex is dosed at 10 to 20 mg/kg/day for two seizure syndromes and 25 mg/kg/day for a third,¹¹ which works out at roughly 700 to 1,750 mg a day for a 70 kg adult. By contrast, the average CBD gummy in a 2025 analysis of 56 products held 21.4 mg.²²

Setting	Daily CBD dose	What was seen
Epidiolex label	10 to 25 mg/kg	Listed interactions; dose-related liver enzyme rises¹¹
Warfarin case report	About 1,050 mg when INR peaked	INR 2.22 to 6.86⁷
Probe-drug study	640 mg (single dose)	CYP2C19, 2C9, 3A inhibition²
HYPER-H21-4	225 to 450 mg	About 5 mmHg lower 24-hour systolic⁵
FDA healthy-adult studies	5 mg/kg (about 350 mg)	Citalopram exposure up 43%; liver enzyme rises in 5.6%^14,23
Dispensary oil case	About 5 mg	No INR change¹⁹

Low doses lower the risk; they do not remove it. CBD’s half-life after repeated dosing is 56 to 61 hours,¹¹ so it accumulates with daily use. Labels are also unreliable: in the gummy study, 70% of products differed from their stated dose by more than 10%.²² Our comparison of CBD gummies and CBD oil explains why taking CBD with a fatty meal can raise exposure several-fold, and the Epidiolex label puts that food effect at about five-fold for peak levels.¹¹

A 2024 systematic review found warfarin, valproate, tacrolimus and sirolimus were the narrow-range drugs most often involved in reported cannabinoid interactions; its authors built a free checker, CANN-DIR.²⁴ Overlap is common: in a 2025 emergency department survey, antihypertensives were the second most common prescription category among CBD users at risk of an interaction.²⁵

What to ask your pharmacist before taking CBD with blood pressure medication

Which enzymes clear each of my medicines? Ask specifically about CYP3A4, CYP2C19 and CYP2C9.
Do any of them have a narrow therapeutic range? Warfarin is the obvious one; ask whether extra INR checks make sense when starting or changing CBD.
Does any of my medicines need activating by the liver? Clopidogrel and losartan are examples where inhibition could change the active drug.
Should I check my blood pressure at home for the first weeks, and what reading should prompt a call?
Bring the product. Show the CBD milligrams per serving, how many servings you take, and the batch certificate of analysis. Our checklist on what to check when buying CBD online covers how to read one.
Ask about THC. Full-spectrum products contain some THC, which CBD can raise.² Our explainer on CBD isolate vs full spectrum sets out the trade-offs, and whether CBD can fail a drug test matters if you are tested.

Tell the prescriber as well as the pharmacist, and avoid starting CBD at the same time as a new prescription so any change can be traced. If dependence is a worry, our article on whether CBD is addictive covers what the abuse-potential studies found. The legal status of retail products is also shifting, with the new federal hemp THC limit, which caps finished products at 0.4 mg total THC per container, due to take effect on 11 December 2026.²⁶

Frequently asked questions

Can I take CBD with blood pressure medication?

Sometimes, but only after checking with a pharmacist or prescriber. CBD slows liver enzymes that clear some heart medicines and can lower blood pressure slightly at high doses. ACE inhibitors such as lisinopril are not metabolised by the liver, so enzyme effects are unlikely; amlodipine, losartan and warfarin carry more theoretical or documented risk.^11,2 Dose and the specific drug matter.

Does CBD lower blood pressure?

In small trials, yes, by a few points. A single 600 mg dose lowered resting systolic pressure by about 6 mmHg in nine healthy men, and a five-week trial in hypertension found 24-hour systolic pressure about 5 mmHg lower.^15,5 Tolerance appeared within a week in one study. These doses are far above typical retail servings, and CBD is not an approved blood pressure treatment.

Is CBD safe with blood thinners like warfarin?

Warfarin is the best-documented CBD interaction. Case reports describe INR rising, in one case from 2.22 to 6.86, with warfarin doses later cut by 20 to 30%.^7,18 Most involved high prescription doses. A systematic review found no evidence either way for newer anticoagulants.⁸ Anyone on warfarin should discuss extra INR monitoring before starting CBD.

Does CBD interact with amlodipine?

No study has tested the combination directly. Amlodipine is cleared by CYP3A4, and its label warns that CYP3A inhibitors can raise levels and cause low blood pressure or swelling.¹ CBD only mildly inhibited CYP3A in a human probe study,² so a large effect at retail doses seems unlikely, but monitoring blood pressure when starting is sensible.

Do low-dose CBD gummies cause drug interactions?

The risk is lower at low doses, but not zero. Most documented interactions involved hundreds of milligrams a day, while the average gummy in one analysis held about 21 mg.²² However, CBD accumulates with daily use, labels are often inaccurate and fatty meals raise absorption. People on warfarin or other narrow-range drugs should treat any dose as relevant.

Sources

Amlodipine besylate tablets: prescribing information (drug interactions, CYP3A inhibitors and simvastatin). Accessed via MedLibrary, October 2026. medlibrary.org
Bansal S, Zamarripa CA, Spindle TR, Weerts EM, Thummel KE, Vandrey R, Paine MF, Unadkat JD. Evaluation of Cytochrome P450-Mediated Cannabinoid-Drug Interactions in Healthy Adult Participants. Clin Pharmacol Ther. 2023;114(3):693-703. DOI: 10.1002/cpt.2973. PMID: 37313955. pubmed.ncbi.nlm.nih.gov
TOPROL-XL (metoprolol succinate): prescribing information, clinical pharmacology. Accessed via MedLibrary, October 2026. medlibrary.org
Lisinopril tablets: prescribing information, pharmacokinetics. Accessed via MedLibrary, October 2026. medlibrary.org
Dujic G, Kumric M, Vrdoljak J, Dujic Z, Bozic J. Chronic Effects of Oral Cannabidiol Delivery on 24-h Ambulatory Blood Pressure in Patients with Hypertension (HYPER-H21-4): A Randomized, Placebo-Controlled, and Crossover Study. Cannabis Cannabinoid Res. 2024;9(4):979-989. DOI: 10.1089/can.2022.0320. PMID: 37093160. pubmed.ncbi.nlm.nih.gov
COZAAR (losartan potassium): prescribing information, clinical pharmacology and drug interactions. Accessed via MedLibrary, October 2026. medlibrary.org
Grayson L, Vines B, Nichol K, Szaflarski JP; UAB CBD Program. An interaction between warfarin and cannabidiol, a case report. Epilepsy Behav Case Rep. 2018;9:10-11. DOI: 10.1016/j.ebcr.2017.10.001. PMID: 29387536. pubmed.ncbi.nlm.nih.gov
Smythe MA, Wu W, Garwood CL. Anticoagulant drug-drug interactions with cannabinoids: A systematic review. Pharmacotherapy. 2023;43(12):1327-1338. DOI: 10.1002/phar.2881. PMID: 37740600. pubmed.ncbi.nlm.nih.gov
PLAVIX (clopidogrel bisulfate): prescribing information, boxed warning and section 7.2. Revised May 2025. drugs.com
Medsafe (New Zealand Medicines and Medical Devices Safety Authority). Statins and CYP Interactions. Prescriber Update 35(1). 6 March 2014. medsafe.govt.nz
US Food and Drug Administration. EPIDIOLEX (cannabidiol) oral solution: full prescribing information. Revised March 2024. accessdata.fda.gov
Nasrin S, Watson CJW, Perez-Paramo YX, Lazarus P. Cannabinoid Metabolites as Inhibitors of Major Hepatic CYP450 Enzymes, with Implications for Cannabis-Drug Interactions. Drug Metab Dispos. 2021;49(12):1070-1080. DOI: 10.1124/dmd.121.000442. PMID: 34493602. pubmed.ncbi.nlm.nih.gov
US Food and Drug Administration. Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Accessed October 2026. fda.gov
Salcedo P, Volpe DA, Chaturbedi A, Shah A, Krishna A, Hyland PL, et al. Clinical Study to Evaluate Drug Interactions of Cannabidiol with Citalopram and Morphine in Healthy Adults. Clin Pharmacol Ther. 2026;119(4):1095-1104. DOI: 10.1002/cpt.70219. PMID: 41622700. pubmed.ncbi.nlm.nih.gov
Jadoon KA, Tan GD, O’Sullivan SE. A single dose of cannabidiol reduces blood pressure in healthy volunteers in a randomized crossover study. JCI Insight. 2017;2(12):e93760. DOI: 10.1172/jci.insight.93760. PMID: 28614793. pubmed.ncbi.nlm.nih.gov
Sultan SR, O’Sullivan SE, England TJ. The effects of acute and sustained cannabidiol dosing for seven days on the haemodynamics in healthy men: A randomised controlled trial. Br J Clin Pharmacol. 2020;86(6):1125-1138. DOI: 10.1111/bcp.14225. PMID: 32128848. pubmed.ncbi.nlm.nih.gov
Dragun T, Brown CV, Tulppo MP, Obad A, Dujić Ž. The Influence of Oral Cannabidiol on 24-h Ambulatory Blood Pressure and Arterial Stiffness in Untreated Hypertension: A Double-Blind, Placebo-Controlled, Cross-Over Pilot Study. Adv Ther. 2023;40(8):3495-3511. DOI: 10.1007/s12325-023-02560-8. PMID: 37291376. pubmed.ncbi.nlm.nih.gov
Cortopassi J. Warfarin dose adjustment required after cannabidiol initiation and titration. Am J Health Syst Pharm. 2020;77(22):1846-1851. DOI: 10.1093/ajhp/zxaa268. PMID: 33016308. pubmed.ncbi.nlm.nih.gov
Thomas TF, Metaxas ES, Nguyen T, Bennett W, Skiendzielewski KV, Quinn DH, Scaletta AL. Case report: Medical cannabis-warfarin drug-drug interaction. J Cannabis Res. 2022;4(1):6. DOI: 10.1186/s42238-021-00112-x. PMID: 35012687. pubmed.ncbi.nlm.nih.gov
Lattanzio H, Gregorius T. Should CBD have a “grapefruit warning”? NCPA CBD Source. America’s Pharmacist. April 2024. digitaleditions.sheridan.com
US Food and Drug Administration. Grapefruit Juice and Some Drugs Don’t Mix. Consumer update, content current as of 1 July 2021. fda.gov
Johnson ED, Kilgore MW, Stafford M, Randolph M, Glover M, Babalonis S. Cannabidiol Gummy Products: LC-MS/MS Assessment of Cannabinoid Concentrations. Cannabis Cannabinoid Res. 2025;10(6):710-718. DOI: 10.1089/can.2024.0167. PMID: 40454463. pubmed.ncbi.nlm.nih.gov
Florian J, Salcedo P, Burkhart K, Shah A, Chekka LMS, Keshishi D, et al. Cannabidiol and Liver Enzyme Level Elevations in Healthy Adults: A Randomized Clinical Trial. JAMA Intern Med. 2025;185(9):1070-1078. DOI: 10.1001/jamainternmed.2025.2366. PMID: 40622698. pubmed.ncbi.nlm.nih.gov
Nachnani R, Knehans A, Neighbors JD, Kocis PT, Lee T, Tegeler K, et al. Systematic review of drug-drug interactions of delta-9-tetrahydrocannabinol, cannabidiol, and Cannabis. Front Pharmacol. 2024;15:1282831. DOI: 10.3389/fphar.2024.1282831. PMID: 38868665. pubmed.ncbi.nlm.nih.gov
Geneau H, Kovasala M, Brown G, Holmes S, Hime O, McNally M, et al. Prevalence of Cannabidiol (CBD) Use Among Patients Taking Medications with Known Drug-Drug Interactions: A Cross-Sectional Analysis. J Clin Med. 2025;14(21):7776. DOI: 10.3390/jcm14217776. PMID: 41227172. pubmed.ncbi.nlm.nih.gov
Hemp Law Group. Federal hemp ban 2026: where things stand. 2026. hemplawgroup.com

This article is for educational purposes only and is not medical or legal advice. Products discussed here are not intended to diagnose, treat, cure or prevent any disease. Laws vary by location and change often, so verify the rules that apply where you are. Always talk to a licensed healthcare provider before use, especially if you are under 21, pregnant or nursing, taking medication, or managing a health condition.

CBD and Blood Pressure Medication: Interactions, Evidence and What to Ask Your Pharmacist