CBD Before Surgery: What Your Anesthesia Team Needs to Know
CBD Before Surgery: What Your Anesthesia Team Needs to Know
Tell them. That is the headline, and if you read nothing else, read this: if you use CBD or any cannabis product and you are having a procedure that involves anesthesia, tell your anesthesiologist before the day of surgery.
Not because you are in trouble. Because in 2023 the American Society of Regional Anesthesia and Pain Medicine published the first US guidelines on managing patients who use cannabis and cannabinoids around surgery, and the headline recommendation is that every patient should be screened for cannabis use before a procedure. Those guidelines have been reviewed by the American Society of Anesthesiologists and found to be in agreement with their own recommendations.
Your anesthesia team is asking because it changes what they need to plan for — not because they are judging you.
For the wider picture on CBD safety, see our CBD safety guide.
What the guidelines actually say
There is a lot of confident misinformation on this subject, so here is what the ASRA guidance says, including the parts that are inconvenient for a tidy answer.
Screen every patient. All patients undergoing procedures requiring anesthesia should be asked about cannabis use. Clinicians should assess for acute intoxication and be aware of interactions with other medications, anesthetics, and physiological changes.
Delay elective surgery after recent smoking. The guidance advises holding off on elective procedures until at least two hours after a patient last smoked, because of concerns about airway resistance and respiratory adverse events. This is specific to smoking or inhalation.
On stopping beforehand, the guidance is deliberately non-committal. ASRA cannot recommend for or against routine tapering of cannabis and cannabinoids in the perioperative period, and does not suggest that patients abstain for a week before major surgery — because the published evidence does not support a specific recommendation either way.
That last point is worth sitting with. If you read an article that confidently tells you to stop CBD exactly seven days before surgery, that is not what the guidelines say. The honest position is that there is no established, evidence-based stopping window, which is precisely why the decision belongs to your care team and not to a blog.
Anesthetic dosing may need adjusting. The guidance says consideration should be given to adjusting induction and maintenance doses based on clinical presentation and the timing of last use.
Why it matters even though CBD isn't intoxicating
People often assume the warning applies to THC and not to a THC-free hemp product. There are two reasons that assumption is not safe.
The drug interaction pathway. CBD inhibits several cytochrome P450 liver enzymes. Those same enzymes metabolise a long list of drugs used in and around surgery — including some sedatives, anticoagulants and pain medications. Clinical pharmacology research has documented CBD's inhibition of CYP2C9, CYP2C19, CYP3A and CYP1A2, and the clinically significant interactions that follow. Your anesthesiologist plans doses around how quickly your body clears drugs. CBD can change that.
Anticoagulants deserve specific mention. Interactions between CBD and warfarin have been reported, and warfarin has a narrow therapeutic window — the margin between an effective dose and a dangerous one is small. If you take an anticoagulant and CBD, that is a conversation to have well before a procedure, not on the morning of one.
Post-operative pain management. Your pain plan after surgery is built on assumptions about your baseline. Anything that alters how you metabolise analgesics is relevant to it.
What to disclose, and when
Bring it up at your pre-operative appointment, not on the day. If there is a change to make, that is when there is time to make it.
Tell them:
- What you take — CBD tincture, topical, gummy, or a THC-containing product. These are genuinely different and the distinction matters.
- How much, and how often. Milligrams per dose and doses per day.
- How you take it. Sublingual, swallowed, inhaled, topical. The two-hour rule above applies specifically to inhalation.
- When you last took it.
- Everything else you take — prescriptions, over-the-counter medicines, and supplements. Interactions are the main concern and they are additive.
Bring the bottle or a photo of the label if you are unsure of the numbers. That is more useful than a recollection.
Why honesty here is genuinely safe
Some people hesitate because of the legal history of cannabis. Two things are worth saying plainly.
Your anesthesiologist's interest in this is clinical. Undisclosed use is a patient safety problem, which is precisely why the professional bodies moved to universal screening — the goal is to make the question routine so that answering it is unremarkable.
And a hemp-derived, THC-free product is a legal consumer product. There is nothing to admit to. But the interaction risk does not care about the legal category, which is why it still needs saying.
What we are not telling you to do
We are not telling you to stop taking CBD before surgery, and we are not telling you to continue. The guidelines do not support a general recommendation in either direction, and we are not going to invent one.
What we are telling you is to disclose it and let the people responsible for your anesthesia make the call. That is the whole message.
Frequently asked questions
Do I need to stop CBD before surgery? There is no established evidence-based stopping window — ASRA explicitly cannot recommend for or against routine tapering. Ask your anesthesia team, who will decide based on your medications and procedure.
Does a CBD topical count? Mention it. Systemic absorption from a topical is minimal, but your team should have the full list and it is not your job to decide what is relevant.
Will disclosing this delay my surgery? For elective procedures the guidance advises waiting at least two hours after inhalation. For other routes, disclosure is about planning, not postponement.
What if I forgot to mention it beforehand? Tell them as soon as you remember, including on the day. Late information is far better than none.
Does CBD interact with anesthesia drugs? CBD inhibits cytochrome P450 enzymes that metabolise many drugs, including some used perioperatively. This is why the disclosure matters even for a THC-free product.
Sources
- American Society of Regional Anesthesia and Pain Medicine. All Patients Should be Screened for Cannabis Use Before Surgery, First U.S. Guidelines Recommend (2023). https://asra.com/news-publications/asra-update-item/asra-updates/2023/01/03/all-patients-should-be-screened-for-cannabis-use-before-surgery-first-u.s.-guidelines-recommend
- American Society of Anesthesiologists. Cannabis and Surgery. https://madeforthismoment.asahq.org/preparing-for-surgery/risks/cannabis-surgery-made-moment/
- Systematic review of drug-drug interactions of delta-9-tetrahydrocannabinol, cannabidiol, and Cannabis. Frontiers in Pharmacology, 2024. https://pubmed.ncbi.nlm.nih.gov/38868665/
- Evaluation of Cytochrome P450-Mediated Cannabinoid-Drug Interactions in Healthy Adult Participants. Clinical Pharmacology & Therapeutics, 2023. https://pubmed.ncbi.nlm.nih.gov/37313955/
- Cytochrome P450–Catalyzed Metabolism of Cannabidiol to the Active Metabolite 7-Hydroxy-Cannabidiol. https://pmc.ncbi.nlm.nih.gov/articles/PMC11025033/
- U.S. Food and Drug Administration. EPIDIOLEX (cannabidiol) oral solution, prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/210365s023lbl.pdf
This article is for general information and is not medical advice. CBD is not approved by the FDA to diagnose, treat, cure or prevent any disease. Always disclose all supplements and medications to your surgical and anesthesia team.