Which inhalational anaesthetic agent undergoes the greatest degree of hepatic metabolism, with approximately 20% of the absorbed dose biotransformed in the liver?
- A Sevoflurane
- B Halothane ✓
- C Enflurane
- D Isoflurane
Correct answer: B. Halothane
Explanation
Halothane is extensively metabolised, about 20 to 25% of the absorbed dose, mainly via CYP2E1 mediated oxidation to trifluoroacetic acid, with a smaller reductive pathway that generates reactive intermediates. This metabolism underlies both its risk of fulminant halothane hepatitis after repeated exposure and its long context sensitive half time for washout. The best distractor is sevoflurane, but it undergoes only about 3 to 5% metabolism despite liberating fluoride.
Reference: Morgan and Mikhail's Clinical Anesthesiology, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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