Cannabis: Essential Information in Anesthesia

Abstract

Cannabis, a cannabinoids substance, is transformed by cytochrome P-450 enzyme to lipophilic metabolites, tetrahydrocannabinol and cannabidiol, which binding with numerous receptors in the Endocannabinoid system. Drug administration via inhalation route is suitable to relieve acute illness since it can increase plasma concentration abruptly and effectively in 15-30 min. Oral route, however, is sometimes inefficient as absorption is irregular. The onset of action is 30-90 min and should last for 4-12 hr. It is apposite for chronic, long-term applications. Drug acts by stimulation and followed by depression. It affects brain and central nervous system causing cognitive dysfunction and psychosis, irritates bronchial airway inducing chronic cough, stimulates sympathetic nervous system initiating increased cardiac oxygen consumption and cerebral vasoconstriction. Subsequently, body hypothermia, immune system deficiency and simply prone to infections are commonly seen. Anesthesia personnel have to handle cannabis patients as good as ones with alcoholism or drug addiction. During perioperative anesthetic management, it is necessary to beware of drug interaction, volume, duration and route of consumption, last concentration and dosage, severe symptoms of nausea and vomiting as well as airway hypersensitivity and shivering. In addition, cannabis has synergistic effects on induction agents, sedatives, hypnotics, analgesics and muscle relaxants but antagonistic to the volatile agents.