In 1996, California became the first state in the nation to legalize cannabis for medical purposes when voters passed Proposition 215. Since that time, the state has been joined by 37 other U.S. states, as well as the District of Columbia, Guam and Puerto Rico, in legalizing medicinal cannabis.

Due to this vast expansion of the legal medicinal cannabis market, more Americans than ever before turn to cannabis to help them with pain management. In fact, a recent survey shows more than one-fourth of U.S. adults suffering from chronic pain have turned to cannabis consumption to manage their discomfort, eschewing over-the-counter pain medications and prescribed opioids from their doctors.¹

There is still much we in the medical community—anesthesiologists, surgeons and perioperative physicians—don’t know about the medical benefits of cannabis or how it affects treatment. Additionally, the increased use of cannabis by patients seeking pain relief only underscores the urgent need for research.

Compounding the problem, the federal government—despite the fact that the vast majority of U.S. states have some form of cannabis legalization in place—still classifies cannabis as a Schedule I drug, meaning that it “has a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision.” This also limits the research that can be done.

That’s why a dozen colleagues—anesthesiologists, chronic pain physicians and a patient advocate—and I embarked on an effort to create consensus guidelines on the management of the perioperative patient on cannabis.²

These evidence-based recommendations are based on our collective experience combined with an extensive literature review.

Among the nine questions considered, we looked at the types of questions that patients should be asked, examined when it would be best to postpone surgery, discussed how to handle situations where patients are using cannabis and opioids for pain prior to surgery, and considered how to adjust levels of anesthesia with cannabis users.

While there were many findings and recommendations of note, it all starts with increased communication between doctor and patient. We need to directly ask patients about their cannabis use prior to surgery so we can avoid any potential adverse effects (e.g., increased pain post-surgery) when cannabis is combined with anesthesia.

Physicians should ask patients:

• what type of cannabis product was used;
• how it was used;
• whether it was smoked or ingested;
• the amount;
• how recently it was used; and
• the frequency of use.

The reason for this is if the patients’ cannabis use is regular or heavy when they are put under anesthesia, they could face a higher risk for heart problems, potentially even a heart attack. The patient should be aware of these risks, and both patient and doctor should have all the information they need to determine whether it may be necessary to delay surgery.

In the case of patients who are pregnant, the same open line of communication is a must. Asking questions is key to letting future parents know the risks of cannabis use to the unborn child.

This is why it is very important for patients to be honest with their doctors about their use of cannabis. Not divulging their cannabis use habits to their doctors may lead to inadequate anesthesia or postoperative pain control.

Even though some patients use cannabis therapeutically to help relieve pain, studies have shown regular users may have more pain and nausea after surgery, not less, and may need more medications, including opioids—which is what many users said they hoped to avoid in the first place when they began using cannabis to treat their pain.³

As we’re finding out, the cannabis landscape in the United States changes on an almost daily basis. Cannabinoid use in the perioperative setting poses significant medical implications.

These guidelines are not intended to replace clinical judgment but rather promote improved patient communication and possibly improved outcomes.

We hope these guidelines will aid clinicians and researchers in their pursuit of optimal patient care.

Editor’s note: The views expressed in this commentary belong to the author and do not necessarily reflect those of the publication.

References

1. Bicket MC, Stone EM, McGinty EE. Use of cannabis and other pain treatments among adults with chronic pain in US states with medical cannabis programs. JAMA Netw Open. 2023;6(1):e2249797.
2. Shah S, Schwenk ES, Sondekoppam RV, et al. ASRA Pain Medicine consensus guidelines on the management of the perioperative patient on cannabis and cannabinoids. Reg Anesth Pain Med. 2023;48(3):97-117.
3. Cannabis use increases pain after surgery, study shows. Accessed January 15, 2023. www.asahq.org/about-asa/ newsroom/ news-releases/ 2022/ 10/ cannabis-use-increases-pain-after-surgery-study-shows