Perioperative care of cannabis users: A comprehensive review of pharmacological and anesthetic considerations.

According to the 2015 National Survey on Drug Use and Health, marijuana continues to be the most common illicit recreational drug used in the US. Cannabis is associated with systemic reactions that potentially affect perioperative outcomes. We have reviewed the most important pharmacological aspects and pathophysiological effects that should be considered during the perioperative management of chronic cannabis/cannabinoids users. The synthetic analogues provide higher potency with increased risk for complications. High cannabinoid liposolubility favors rapid accumulation in fatty tissue which prolongs its elimination up to several days after exposure. The multi-systemic effects of cannabinoids and their pharmacological interactions with anesthetic agents may lead to serious consequences. Low doses of cannabinoids have been associated with increased sympathetic response (tachycardia, hypertension and increased contractility) with high levels of norepinephrine detected 30 min after use. High doses enhance parasympathetic tone leading to dose-dependent bradycardia and hypotension. Severe vascular complications associated with cannabis exposure may include malignant arrhythmias, coronary spasm, sudden death, cerebral hypoperfusion and stroke. Bronchial hyperreactivity and upper airway obstruction are commonly reported in cannabis users. Postoperative hypothermia, shivering and increased platelet aggregation have been also documented.