Marijuana is the most common drug in the United States, used by more than 52 million people, including one in three young adults 18-25. Although many users believe it to be completely benign, it can interact with anesthesia, increase the risk for complications and may worsen pain and nausea after the procedure, increasing the need for opioids or other pain relief medications. That’s why anesthesiologists note it’s important for you to alert your doctors before surgery if you use marijuana, cannabis or cannabinoids for recreational or medical reasons.

Your anesthesiologist needs to know that information to care for you safely during and after the procedure.

The American Society of Anesthesiologists agrees with the American Society of Regional Anesthesia and Pain Medicine guidelines released earlier this year that recommend anesthesiologists screen all patients for cannabis use, asking what type of cannabis product was used, how it was used, the amount and how recently and frequently it was used.

“While more research is needed, early studies suggest cannabis poses increased risks and side effects during surgery,” said ASA President Michael W. Champeau, M.D., FAAP, FASA. “Keeping us informed will help us better care for you if you use cannabis and need surgery.”
Anesthesiologists are medical doctors with the expertise and training to keep you safe during surgery and manage your recovery, including pain relief. They need to know about your use of marijuana or other cannabis products 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.

To help determine your risk factors and plan for your care before, during and after surgery, your anesthesiologist will ask questions, which may include:

Do you use cannabis?

What types of cannabis products do you use?

What methods do you use (smoking, 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?

In addition to screening patients for cannabis use, your anesthesiologist may recommend postponing elective surgery in patients taking cannabis who have an altered mental status or whose decision-making is affected at the time of surgery. They also will counsel frequent, heavy cannabis users on the potentially negative effects of its use on postoperative pain control and pregnant patients on the risks of cannabis use to their unborn child.

ASA offers additional information on the guidelines and use of cannabis before surgery, answering questions such as:

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

How can use of cannabis affect my recovery from surgery?

Could I experience cannabis withdrawal symptoms after surgery?

How do I tell my anesthesiologist about my cannabis use?

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