Carfentanil, the opioid that anesthetists should know

Abstract

Carfentanil is a synthetic opioid derived from fentanyl. It is a μ-opioid receptor agonist with a potency 10,000 times greater than morphine and 30 times greater than fentanyl. It's currently only used on animals or in small doses for research purposes, but its use as an illicit drug has been increasing in the world in recent years. Little is known about its pharmacokinetics and pharmacodynamics in humans, most of the information being extrapolated from animal studies. The drug's high potency could be explained by its high lipophilicity, large distribution volume and potential active metabolites. It's a potent analgesic and sedative, with a large therapeutic index, but small lethal doses. Carfentanil poisoning is similar to any opioid toxidrome, the most common symptoms being loss of consciousness and respiratory depression. Like the rest of opioids, its antidote is naloxone, but multiple doses may be necessary for treating intoxications.