Cannabis and Surgery

Medically reviewed by David M. Dickerson, MD, August 8, 2023.

Doctors are still learning about the effect of a patient’s use of cannabis, including marijuana and CBD, on the patient’s surgical risks and recovery. But enough is known to warrant precautions regarding cannabis use shortly before and after surgery. The potential risks make it critically important for patients to share information about their cannabis use with the anesthesiologist before surgery.

Why should I tell my anesthesiologist about my use of cannabis?

Anesthesiologists are medical doctors who are specially trained to keep you safe in surgery and manage your recovery, including pain relief. They need to know about your use of marijuana or other cannabis products, including edibles, because studies have shown that their use could affect:

The level of anesthesia you need during surgery.
Your risk for heart or respiratory issues.
The type of medications you may need after surgery to manage your pain.
Your risk for nausea and vomiting.
The likelihood of cannabis withdrawal symptoms after surgery.
The potential for adverse interactions with other medications.

Being able to assess your risk factors allows your anesthesiologist to make appropriate plans for your care before, during, and after surgery. It also helps them prepare for and respond to any complications that may arise. This can help you avoid an unanticipated hospital admission after outpatient surgery, a longer hospital stay after inpatient surgery, or readmission following discharge.

Smoking marijuana shortly before surgery could increase the patient’s risk of suffering a heart attack during or after surgery.

Can I smoke marijuana before surgery?

It is not advisable to smoke marijuana (often referred to as “weed” or “pot”) on the day of surgery. Guidelines from the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine) advise physicians to hold off on elective surgery until at least two hours after the patient last smoked.

The guidelines focus on the use of cannabis and cannabinoids in relation to surgery. They were developed by a committee of 13 experts—including anesthesiologists, chronic pain physicians, and a patient advocate—based on an extensive review of published research and on their own experiences.

Regarding the smoking of marijuana before surgery, the guidelines advise that:

Smoking weed can significantly increase heart rate and blood pressure within the first two hours following use and may increase the patient’s risk of suffering a surgery-related heart attack.
Same-day smoking of marijuana outside the two-hour window may still carry some risk, although the evidence is not as strong as for use within two hours.
Smoking weed the day before surgery might have a negative impact, especially for someone who smokes it frequently. You may be advised to stop smoking marijuana one or more days before surgery unless you use it for a medical reason.

Tell your anesthesiologist if you were hoping to use cannabis to get a good night’s sleep, reduce anxiety, or relax before surgery. They can use their medical expertise to suggest other options that will not increase your risk.

If you are using cannabis for a medical reason, consult with your anesthesiologist or clinical team before you stop using it.

Can I smoke marijuana after surgery?

Research has not established when it’s safe to resume smoking weed following surgery. The recommendations for a specific patient can be influenced by the type of surgery and the patient’s medical history, so talk with your anesthesiologist, surgeon, or another member of your care team.

Here are some factors to consider:

The anesthetic used during surgery can affect your judgment for up to 24 hours, which is why patients are advised not to drink alcohol during that time. The same advice applies to marijuana.
Smoking can irritate your airway and cause you to cough. Coughing can put stress on incisions, affect blood pressure, and increase the risk of bleeding.
Some prescribed pain medicines can affect your ability to pay attention, think clearly, make sound decisions, and solve problems. Adding cannabis to the mix could worsen the impact. This applies especially if you are taking opioids or other sedating medications, including benzodiazepines, sleep aids, and gabapentin or pregabalin.
The anesthesiologist can suggest other options to reduce pain, increase comfort, and lower anxiety.

Can I take cannabinoid-based medications before and after surgery?

It may depend on the medication, but there are some that you can and should continue to take. For example, ASRA Pain Medicine’s guidelines advise against abruptly stopping some FDA-approved medications for chemotherapy-induced nausea and vomiting, HIV/AIDS-associated wasting, and rare forms of epilepsy. These medications include:

Some synthetic THCs, such as dronabinol.
Synthetic analogs of delta-9-THC, such as nabilone.
Cannabis-derived options, such as the CBD-containing product Epidiolex.

How can use of cannabis affect my recovery from surgery?

Research shows that people who use cannabis regularly may experience more pain and nausea after surgery than those who do not use cannabis. Prolonged exposure to cannabis may create this higher sensitivity to pain because cannabinoid receptors in the spine are in the same area as opioid receptors.

After surgery, you may need more medication for pain to manage your discomfort than a nonuser of cannabis would need. Opioids may be considered, but only after other medications have been tried first. Cannabis will not be an option in the hospital, as it is not FDA-approved for this purpose.

Those who regularly use cannabis may experience more pain and nausea after surgery than those who don’t use cannabis, and they may need more or different types of medication to manage their discomfort.

Could I experience cannabis withdrawal symptoms after surgery?

Yes, those who use cannabis can experience withdrawal symptoms after surgery, especially if they use it frequently. However, studies suggest there is minimal risk of developing withdrawal for someone who uses products containing CBD only.

When discussing your cannabis use with your anesthesiologist, ask if withdrawal symptoms are likely and what the plan is for addressing them if they occur.

How do I tell my anesthesiologist about my cannabis use?

You might not meet your anesthesiologist until the day of surgery, so you should inform the surgeon’s office ahead of time if you regularly use cannabis. They can then connect you with someone from the anesthesiologist’s office for evaluation and instructions.

Be assured that the anesthesiologist will use the information you provide solely to plan for your surgery and recovery. They will not judge your behavior, and they will share the information only with medical team members who need to know. If there are other people in the room when you are speaking with the anesthesiologist and you want more privacy for your discussion, do not hesitate to ask for it.

What questions will the anesthesiologist ask about my cannabis use?

Your anesthesiologist will ask you a series of questions to help determine whether or how to adjust the plan for your surgery and recovery. These questions may include:

Do you use cannabis?
What types of cannabis products do you use?
What methods do you use (smoking, consuming edibles, etc.)?
How often do you use cannabis products, and in what amounts?
When was the last time you used cannabis?
Are you using cannabis to manage pain?