Which inhaled anesthetic has substantial hepatic metabolism, around 30%?

Which inhaled anesthetic has substantial hepatic metabolism, around 30%?

• A. Halothane
• B. Isoflurane
• C. Desflurane
• D. Sevoflurane

Answer: (A)

Understanding how much each inhaled anesthetic is metabolized by the liver helps explain why halothane stands out here. Halothane is uniquely turned over by hepatic enzymes to reactive metabolites, with roughly a third of the dose undergoing metabolism. That level of hepatic processing is considered substantial and underlies the historical concern for halothane-related hepatitis, especially with repeated exposure or in susceptible patients. By contrast, the other common volatile anesthetics are metabolized far less by the liver. Isoflurane and desflurane have minimal hepatic metabolism (only a tiny fraction). Sevoflurane is more than the others but still only a few percent metabolized, not near the 30% mark. So the standout agent with substantial hepatic metabolism around 30% is halothane.

Understanding how much each inhaled anesthetic is metabolized by the liver helps explain why halothane stands out here. Halothane is uniquely turned over by hepatic enzymes to reactive metabolites, with roughly a third of the dose undergoing metabolism. That level of hepatic processing is considered substantial and underlies the historical concern for halothane-related hepatitis, especially with repeated exposure or in susceptible patients.

By contrast, the other common volatile anesthetics are metabolized far less by the liver. Isoflurane and desflurane have minimal hepatic metabolism (only a tiny fraction). Sevoflurane is more than the others but still only a few percent metabolized, not near the 30% mark. So the standout agent with substantial hepatic metabolism around 30% is halothane.