Authors: Irvine D et al.
Anesthesia Patient Safety Foundation Newsletter, volume 41, number 1, February 2026.
Summary
This article provides an updated review of perioperative considerations for patients who use cannabis, reflecting the growing prevalence of both medical and recreational use in the United States. As legalization expands and cannabis consumption becomes more common, anesthesia professionals must anticipate its effects on anesthetic drug requirements, cardiovascular stability, airway reactivity, and postoperative pain control.
Cannabis exerts its effects primarily through phytocannabinoids such as tetrahydrocannabinol and cannabidiol, which interact with the endocannabinoid system via CB1 and CB2 receptors distributed throughout the central nervous system and peripheral tissues. These interactions influence analgesia, cognition, autonomic tone, inflammation, and immune function. Acute intoxication can cause tachycardia, hypertension or hypotension, anxiety, psychosis, and impaired cognition, while chronic use may lead to tolerance, altered anesthetic requirements, and withdrawal symptoms after cessation.
Preoperative evaluation is emphasized as a critical step. A thorough history should document the type of cannabis product used, route of administration, frequency and dose, time since last use, prior adverse effects, and concomitant use of other substances such as alcohol, opioids, or sedatives. Acute intoxication represents the greatest perioperative risk and may precipitate hemodynamic instability or emergence agitation. Elective procedures should be postponed until the patient is clinically sober, particularly in individuals with underlying cardiovascular disease.
Intraoperatively, accumulating evidence suggests that regular cannabis users may require higher doses of intravenous and volatile anesthetic agents to achieve adequate depth of anesthesia. Meta-analyses and observational studies demonstrate increased requirements for propofol, inhalational anesthetics, and sedative agents such as fentanyl and midazolam. Cannabis may also interact with cytochrome P450 enzymes, creating the potential for drug–drug interactions with commonly used anesthetic and vasoactive medications. Inhaled cannabis use may increase airway hyperreactivity, placing patients at higher risk for bronchospasm.
Postoperatively, cannabis use has been associated with higher pain scores and increased opioid consumption compared with nonusers. Multimodal analgesia strategies using nonopioid adjuncts are recommended to mitigate these effects. Withdrawal symptoms, including irritability, anxiety, nausea, and sleep disturbance, may occur one to two days after cessation and persist for up to two weeks, necessitating clinical awareness and supportive management.
The authors conclude that routine screening for cannabis use, individualized anesthetic planning, careful intraoperative titration of anesthetics, and proactive postoperative pain management are essential to optimize safety. As evidence continues to evolve, anesthesia professionals must remain informed and adaptable to ensure safe perioperative care for this growing patient population.
Key Points
Cannabis use is increasingly common and has important perioperative implications
Thorough preoperative screening should document product type, dosing, route, and timing of last use
Acute intoxication increases anesthetic risk and warrants postponement of elective surgery
Regular cannabis users may require higher doses of intravenous and inhalational anesthetics
Cannabis use may increase airway reactivity and cardiovascular instability
Postoperative pain scores and opioid requirements are often higher in cannabis users
Withdrawal symptoms may occur after cessation and should be monitored
Thank you to the Anesthesia Patient Safety Foundation for allowing us to summarize and share this patient safety–focused article from the APSF Newsletter.