Which inhalant anesthetic is rapidly induced and recovered and has about 3% hepatic metabolism?

• A. Sevoflurane
• B. Guaifenesin
• C. Pilocarpine
• D. Xylazine

Answer: (A)

Rapid induction and recovery with only limited liver metabolism describe a volatile anesthetic that is cleared quickly from the body, mainly through the lungs, due to low blood-gas solubility and minimal hepatic processing. Sevoflurane fits this pattern well: it has relatively low solubility in blood, so it moves rapidly into the brain to induce anesthesia and is washed out quickly as the animal exhales, producing a fast wake-up. Only a small portion—about 3%—is metabolized by the liver, so most of the agent leaves unchanged via expiration, reducing duration and metabolic concerns. The other options are not inhalant anesthetics with this profile; guaifenesin is an oral muscle relaxant/expectorant, pilocarpine is a cholinergic drug, and xylazine is an alpha-2 agonist sedative/analgesic. Sevoflurane is the best fit for rapid induction and recovery with roughly 3% hepatic metabolism.