Remifentanil is preferred for neurosurgical procedures requiring rapid wake-up because its context-sensitive half-time remains approximately 3 to 5 minutes irrespective of infusion duration. This property results from its metabolism by:

• A Hepatic cytochrome P450 oxidation
• B Renal tubular secretion unchanged
• C Plasma and tissue nonspecific esterases ✓
• D Glucuronide conjugation in the liver

Explanation

Remifentanil is an ester-linked opioid rapidly hydrolysed by widespread nonspecific blood and tissue esterases to an almost inactive metabolite. Because clearance depends on these ubiquitous enzymes rather than liver or kidney, elimination is extremely rapid and independent of organ function, so the context-sensitive half-time stays near 3 minutes even after hours of infusion. Fentanyl and alfentanil rely on hepatic metabolism, so their context-sensitive half-time rises steeply with infusion duration.

Reference: Morgan and Mikhail's Clinical Anesthesiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.