Before surgery · Lifestyle
Cannabis Before Surgery
Cannabis is common and often legal, but it genuinely interacts with anesthesia. Your anesthetist isn't there to judge — they need to know so they can dose your anesthetic safely and keep your airway and recovery smooth.
The short answer
Why cannabis matters under anesthesia
- You may need more anesthetic. Regular cannabis users often require higher doses to get to sleep and stay asleep — your anesthetist needs to plan for that.
- Airway irritation. Smoked cannabis irritates the airway much like tobacco, raising the chance of coughing, spasm and breathing problems while you're going under.
- Heart and circulation. Cannabis can speed up the heart and change blood pressure, which the team will want to account for.
- Pain and nausea afterward. Heavy use is linked to more pain and more nausea after surgery, so your recovery plan may need adjusting.
Smoked, edible or CBD — they all count
Smoked or vaped cannabis adds the airway irritation of smoke, so stopping a few days ahead (like cigarettes) helps your lungs. Edibles still affect your anesthesia, and because they're food they also matter for your fasting instructions. CBD products — oils, gummies, creams — can interfere with the liver enzymes that break down anesthetic and pain drugs, and their actual strength is often unregulated. Mention all of them.
When to stop
| When | What to do |
|---|---|
| Day of surgery | None at all. Arriving intoxicated can get your surgery postponed for safety and consent reasons. |
| At least 72 hours before | The usual recommendation — lets the acute effects on your airway, heart and brain settle. |
| If you use daily | Tell your team well ahead. Regular use changes your anesthetic needs even between uses, and cutting down before surgery is worth discussing. |
Honesty isn't optional here
Frequently asked questions
How long before surgery should I stop using cannabis?
A common recommendation is to stop at least 72 hours before surgery, and to never use it on the day. If you use it daily, tell your team — regular use changes how you respond to anesthesia even after the immediate effects wear off.
Do I really have to tell my anesthetist?
Yes — it's one of the most useful things you can share. Cannabis affects how much anesthetic you need, your airway, your heart rate and your pain afterward. They've heard it many times and won't judge; they'll use it to make your anesthetic safer.
What if I show up having used cannabis that day?
Being acutely intoxicated on the day can lead the team to postpone your surgery — for your safety, valid consent, and because a cannabis-irritated airway is riskier under anesthesia. If it has happened, be honest rather than hide it.
Do edibles and CBD count?
Yes. Edibles still affect anesthesia and, because they're food, they also matter for fasting. CBD products can interfere with how your liver processes anesthetic drugs and are often unregulated in strength — mention any CBD oils, gummies or creams to your team.