How long should I stop using cannabis before surgery?

Cannabis and Surgery: Preoperative Cessation Timing

If you have more than 7 days before elective surgery, consider weaning or stopping cannabis; if surgery is within 1-6 days, there is no consensus recommendation; if surgery is within 24 hours, do not attempt to wean or stop cannabis. 1

Timing-Based Recommendations

More Than 7 Days Before Surgery

• Begin tapering or cessation at least 7 days preoperatively to reduce risks of analgesic tolerance, cannabis withdrawal syndrome, interference with EEG-based anesthesia monitoring, and postoperative nausea/vomiting. 2
• Target initial reduction to just below significant consumption thresholds (defined below), with the weaning rate guided by patient tolerance. 2, 3
• The Society for Perioperative Assessment and Quality Improvement recommends a 2-week abstinence period as ideal to reduce airway irritability in smokers. 2

1-6 Days Before Surgery

• No consensus exists on whether to wean or stop cannabis during this window. 1
• The Society for Perioperative Assessment and Quality Improvement advises that elective surgery should preferably not occur within 3 days of cannabis use. 2
• Research suggests cannabis effects in acute settings peak at approximately 1 hour post-initiation and last 2-4 hours, with use within 72 hours of general anesthesia advised against. 4

Less Than 24 Hours Before Surgery

• Do not attempt to wean or stop cannabis at this point. 1
• Record the time cannabis was last consumed on the day of surgery. 1

Critical Caveat: Never Delay Surgery

Surgery should never be delayed for cannabis re-evaluation or weaning, as the risks of delaying necessary surgery outweigh concerns about cannabis use. 2, 3

Defining Significant Cannabis Use

Significant consumption warranting preoperative discussion is defined as: 1, 2, 5

• >1.5 g/day of smoked cannabis
• >300 mg/day CBD oil
• >20 mg/day THC oil
• Consuming any cannabis product more than 2-3 times per day with unknown CBD or THC content

Preoperative Screening and Assessment

• Routine screening for cannabis consumption is recommended in all preoperative clinic settings. 1
• Quantify daily cannabis intake in grams per day for dried products or milligrams of CBD/THC per day for oils and edibles. 1, 3
• Document the method of consumption (smoked, vaped, oral, sublingual). 1, 3
• Screen for cannabis use disorder using validated tools (such as the revised Cannabis Use Disorder Identification Test) in patients consuming cannabis more than once per day. 1, 3
• Consider involving addiction medicine or psychiatry specialists for patients with very high consumption. 3

Special Considerations for Therapeutic Cannabis Users

• Involve the cannabis authorizer (prescribing physician) in discussions of cannabis weaning, dose changes, and dose substitution for patients using cannabis therapeutically. 1
• Avoid aggressive CBD weaning without expert guidance, as CBD may mask adverse THC effects. 2, 3
• Never wean CBD while maintaining THC consumption, as this could exacerbate adverse effects of THC. 2, 3

Understanding CBD vs THC Dominance

• Products with CBD:THC ratio >10:1 are considered CBD-dominant. 5
• Products with CBD:THC ratio <10:1 are considered THC-dominant. 5
• Balanced products (1:1 ratio) should always be considered THC-dominant. 1

Perioperative Risks Associated with Cannabis Use

Cannabis use disorder is associated with increased perioperative morbidity and mortality (adjusted odds ratio 1.19; 95% CI, 1.04-1.37) after major elective noncardiac surgery. 6

Specific perioperative concerns include: 2, 4

• Increased cardiac workload, with risk of myocardial infarction and stroke in young chronic users
• Pulmonary complications similar to tobacco smoking
• Airway obstruction and increased anesthetic dosages needed for laryngeal airway placement
• Potential interference with processed EEG monitoring during anesthesia

Intraoperative Management Considerations

• Give extra consideration to regional anesthesia when not contraindicated. 1, 2
• Plan for potentially greater depth of anesthesia during induction and maintenance. 2
• Consider additional PONV (postoperative nausea and vomiting) prophylaxis. 2
• Exercise caution with processed EEG monitoring as cannabis may interfere with readings. 2

Postoperative Vigilance

• Maintain vigilance for cannabis withdrawal syndrome postoperatively. 2
• Consider acute pain service referral for patients with significant preoperative cannabis use. 2
• Monitor for cannabinoid hyperemesis syndrome, characterized by cyclic vomiting that may be relieved by hot showers or baths. 3