How soon before elective surgery or anesthesia should marijuana use be stopped?

Timing of Marijuana Cessation Before Elective Surgery

For high-dose cannabis users (>1.5 g/day smoked, >300 mg/day CBD, or >20 mg/day THC), tapering or cessation should ideally begin at least 7 days before elective surgery, though surgery should never be delayed for cannabis weaning. 1

Risk-Stratified Approach Based on Timing

If ≥7 Days Before Surgery

• Cannabis tapering or cessation can be safely considered and may provide perioperative benefit 1
• Reducing consumption may decrease risks of analgesic tolerance, cannabis withdrawal syndrome (CWS), interference with EEG-based anesthesia monitoring, and postoperative nausea/vomiting 1
• Target initial reduction to just below threshold doses (e.g., from 2 g/day to 1.5 g/day of smoked cannabis) 1
• Weaning should be collaborative with the patient's tolerance guiding the taper rate 1

If 1-6 Days Before Surgery

• No consensus exists on whether to taper during this window 1
• The expert panel could not reach agreement on recommendations for this timeframe due to insufficient evidence 1
• Clinical judgment should guide individual decisions during this period

If <24 Hours Before Surgery

• Do not attempt cannabis weaning or cessation 1
• Tapering this close to surgery may increase risk of acute withdrawal symptoms and exacerbate underlying conditions like chronic pain and anxiety 1
• Document the time of last cannabis consumption on the day of surgery 1

Minimum Abstinence Recommendations

At minimum, elective surgery should preferably not occur within 3 days of cannabis use 1, though ideally a 2-week abstinence period would reduce airway irritability in those who smoke 1. This recommendation from the Society for Perioperative Assessment and Quality Improvement (SPAQI) accounts for acute sympathetic hyperactivity, airway irritability, impaired temperature regulation, and increased risk of perioperative coronary vasospasm 1.

Defining Significant Cannabis Use

Cannabis consumption is considered significant when it exceeds: 1

• 1.5 g/day of smoked cannabis
• 300 mg/day CBD oil
• 20 mg/day THC oil
• Unknown cannabis product used >2-3 times per day

Critical Perioperative Considerations

Preoperative Screening

• Routinely screen all patients for cannabis use in the preoperative clinic 1
• Quantify daily intake in grams/day for dried products or mg/day for CBD/THC content 1
• Screen for cannabis use disorder (CUD) in patients using cannabis more than once daily using validated tools like the revised Cannabis Use Disorder Identification Test 1

Intraoperative Management for Active Users

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

Postoperative Implications

• Anticipate increased postoperative opioid requirements—cannabis users require approximately 30% more opioids (ratio 1.30,95% CI 1.22-1.38) 2
• Expect higher pain scores (mean difference 0.57 points higher) 2
• Maintain vigilance for cannabis withdrawal syndrome 1
• Consider acute pain service referral 1

Important Caveats and Pitfalls

Surgery should never be delayed for cannabis re-evaluation or weaning 1. This is a critical principle—the risks of delaying necessary surgery outweigh concerns about cannabis use.

Avoid aggressive CBD weaning without expert guidance, as CBD may mask adverse THC effects 1. Never wean CBD while maintaining THC consumption, as this could exacerbate THC-related adverse effects 1, 3.

Very high consumption patterns (2-3 times the threshold doses) warrant discussion about specialist consultation with pain medicine, addiction medicine, or psychiatry 1.

For therapeutic cannabis users, involve the cannabis authorizer in all discussions about weaning, dose changes, or substitution 1.

Cannabis affects multiple organ systems perioperatively: acute use causes sympathetic hyperactivity (tachycardia, hypertension), while high doses cause parasympathetic effects (bradycardia, hypotension) 4. Severe vascular complications including coronary spasm, arrhythmias, and stroke have been documented 4. Bronchial hyperreactivity, airway obstruction, increased anesthetic requirements, and postoperative hypothermia are commonly reported 4, 5.