Now, we have detailed, informed information about the possible interactions of cannabis with anesthetic drugs before, during and after surgery. 

The first guidelines on cannabis use and the surgery timeline were published on Jan. 3 by the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine), who acknowledged that up until now there  is “no single document” that summarizes all of these concerns.

The guidance is based on known data and recommendations from the Perioperative Use of Cannabis and Cannabinoids Guidelines Committee—a group composed of 13 anesthesiologists, chronic pain physicians, experts, and patient advocates.

A modified Delphi consensus process was used to make 21 recommendations. The nine-member committee responded to the questions. All 21 recommendations reached full consensus, with over 75% of the required agreement.

Recommendations include: screening patients prior to surgery; delaying elective surgery for patients with altered mental status, impaired decision-making ability at the time of surgery; counseling frequent cannabis users about the possible negative effects on pain management after surgery; and counselling pregnant patients regarding the risks associated with cannabis use.

Treatment of Surgery and Cannabis There are concerns

“While many of the perioperative risks and challenges related to perioperative cannabis, such as how to advise patients preoperatively, the effects of cannabis on anesthetic medications, and the interaction between cannabis, opioids, and pain, have been described in the literature, there is no single document that summarizes all of these concerns and provides evidence-based recommendations,” the document reads.

The document continues, “Flexibility in this clinical practice guideline is intended to enable person-centered decision-making that takes into account an individual’s expected health outcomes and well-being within the context of various regulatory environments.” 

No recommendations were made for the reduction of cannabis administered by other non-smoking routes before surgery “due to current lack of evidence;” the routine tapering of cannabis and cannabinoids before, during, or after surgery; the use of intraoperative electroencephalogram (EEG) in patients who have taken cannabinoids; nor adjusting opioid prescriptions afterward in surgical patients who use cannabinoids.

The authors noted that there are many options for patients who need to be referred for surgery. However, they cautioned against waiting for more than two hours following the last use of cannabis. Patients who depend on medical marijuana should taper before any surgery.

The majority of current recommendations advise that patients should abstain from marijuana for at least 10 days before they undergo surgery. “A recent consensus-based guideline recommended reducing cannabinoid use 7 days prior to surgery (to less than 1.5 g/day of smoked cannabis, 300 mg/day of CBD oil, 20 mg/day of THC oil) while cautioning not to attempt any tapering strategies within 6 days of elective surgery and not to attempt tapering a day prior to surgery.”

The document continues with the range of guidance, “Contrary to this recommendation, recent reviews of perioperative cannabinoids recommended cessation 72 hours prior to surgery. An even more conservative recommendation was recently provided, in which the authors recommended up to 10 days of cessation of oral cannabis consumption.”

Can Cannabis be used to induce anesthesia

While there’s still much to learn about the potential interactions of cannabis and its effects before and after surgery, research is progressing.

A study was published in Baylor University Medical ProceedingsIn 2019, cannabis users may need higher levels of anesthesia than those who don’t use it. Another study, however, found that there was no difference in the effects of marijuana on the digestive tract.

The dentist might also be concerned about cannabis. The strong belief is that cannabis may interact with lidocaine, novocaine and other local anesthetics. THC was found to interact in an unfavorable way with anesthetic medication according to a 1976 study.