Remifentanil is an ultrashort-acting opioid used in anesthesia. Its elimination half-life remains approximately 10 to 20 minutes even after prolonged infusion and is unaffected by hepatic or renal impairment. This pharmacokinetic property is explained by which mechanism of metabolism?

• A Hydrolysis by nonspecific esterases in blood and tissues ✓
• B Rapid glucuronidation in the liver forming inactive metabolites
• C Spontaneous degradation by plasma cholinesterase inherited as an autosomal dominant trait
• D Excretion unchanged via bile with enterohepatic recirculation

Explanation

Remifentanil contains an ester linkage hydrolyzed by nonspecific tissue and plasma esterases, making its clearance independent of organ function. This produces a context-insensitive half-life of about 10 to 20 minutes. Option B is incorrect because glucuronidation is hepatic and would be affected by liver disease. Option C incorrectly suggests an inherited enzyme. Option D describes biliary excretion, which does not apply to remifentanil.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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