Cannabis and Surgery: What Patients Should Know Before Anesthesia and During Recovery

Cannabis use can affect anesthesia, heart and lung function, and pain control after an operation. That does not mean every patient who uses cannabis needs to cancel surgery—but it does mean the surgical and anesthesia teams need accurate information about what was used, how often, how it was taken, and when it was last used.

The most relevant clinical guidance comes from the 2023 ASRA Pain Medicine consensus guidelines on cannabis and cannabinoids around surgery. The guidelines are based on a review of available evidence and expert consensus, and they emphasize individualized planning rather than a single rule that applies to every patient.

Tell your surgical team about all cannabis use

Patients should disclose medical and nonmedical cannabis use during the preoperative assessment. Include smoked or vaped cannabis, edibles, tinctures, oils, concentrates, CBD products, and prescription cannabinoid medicines.

Your clinicians may ask about the product, dose, frequency, route of use, and the time of your last dose. This information helps the anesthesiologist assess possible effects on blood pressure, heart rate, breathing, alertness, medication interactions, and postoperative pain.

Discussing cannabis use is part of routine medical safety—not a reason to withhold care. Concealing recent use can make it more difficult for the anesthesia team to choose medications and monitor you appropriately.

Should you use cannabis before surgery?

Using cannabis shortly before an operation can be unsafe, particularly when the product is smoked or vaped. Cannabis may temporarily increase heart rate and blood pressure, impair judgment, and irritate or narrow the airways. These effects can complicate anesthesia and may increase cardiovascular or respiratory risks.

The ASRA guidelines recommend postponing elective surgery when a patient is intoxicated or unable to provide informed consent. They also advise delaying elective surgery for at least two hours after cannabis has been smoked because of the immediate cardiovascular effects. That minimum is not a guarantee that surgery is risk-free: frequent use, larger doses, other medical conditions, and the type of procedure may lead the team to recommend a longer interval.

Some surgical organizations advise an even more conservative approach. The American College of Surgeons advises patients not to use cannabis products within 72 hours of general anesthesia. Because recommendations can vary by procedure and institution, patients should follow the specific instructions from their surgeon and anesthesiologist rather than choosing a stop time on their own.

Why cannabis matters to anesthesia

Regular cannabis use may be associated with airway problems and a need for different or higher doses of some anesthetic medicines. The evidence is not uniform, and a higher anesthetic requirement is not inevitable, but the possibility is important for the anesthesia team to know in advance.

Smoking cannabis also exposes the airways to irritants. Cannabis can affect the cardiovascular system, while anesthesia and surgery place additional demands on breathing and circulation. These concerns are especially relevant for people with heart disease, lung disease, sleep apnea, pregnancy, or a history of complications with anesthesia.

Do not stop a prescribed cannabinoid medicine abruptly without discussing it with the clinician who manages your treatment. A planned adjustment may be safer than sudden discontinuation, particularly for patients who use cannabis frequently or to manage a serious medical condition.

Can cannabis be used in the hospital?

There is no single nationwide rule requiring every hospital to permit medical cannabis use. Hospital policy, state law, federal restrictions, the product’s form, and the patient’s clinical condition all matter. Many facilities prohibit patients from bringing or self-administering dispensary cannabis, while some may have limited policies for specific circumstances.

A medical cannabis card does not automatically authorize use during a hospital stay. Patients should ask the facility about its policy before admission and should not smoke, vape, or take an edible in the hospital without explicit approval from the care team. Bringing cannabis to the hospital without telling staff can create medication-safety and monitoring problems.

Using cannabis after surgery

Cannabis has not been established as a reliable substitute for standard postoperative pain treatment. Research on its effect on acute surgical pain is limited and inconsistent. In some studies, regular users reported more postoperative pain or nausea and required additional medication, including opioids.

Cannabis can also add to the sedating effects of opioids, benzodiazepines, sleep medicines, and other drugs commonly used after surgery. Combining these substances may increase drowsiness, confusion, impaired coordination, falls, or breathing problems. Edibles create additional concerns because their effects are delayed and can last longer than expected.

Before resuming cannabis, ask the surgeon, anesthesiologist, or prescribing clinician how it fits with your discharge medicines. Do not drive, drink alcohol, operate machinery, or take extra doses of cannabis or pain medication because pain or anxiety remains uncontrolled.

How to prepare for an operation

• Tell the surgical team that you use cannabis, even if it is legal where you live or prescribed for a medical condition.
• Record the product, strength, typical dose, method of use, frequency, and most recent use.
• Follow the facility’s fasting and medication instructions; do not assume that an edible or CBD product is permitted before anesthesia.
• Ask whether your cannabis treatment should be paused, adjusted, or continued under supervision.
• Report recent use on the day of surgery, including use that occurred after your preoperative appointment.
• After discharge, check for interactions before combining cannabis with opioids, sedatives, sleep aids, alcohol, or other centrally acting medicines.

The safest approach is an individualized plan made with the clinicians responsible for the operation and anesthesia. Cannabis use does not automatically rule out surgery, but using it without informing the care team can make anesthesia and recovery less predictable.