Which of the following medications used in office-based or MAC sedation has the SHORTEST context-sensitive half-time, making it most suitable for brief diagnostic procedures requiring rapid recovery?
- A Midazolam
- B Propofol
- C Fentanyl
- D Remifentanil ✓
Explanation
Remifentanil is a unique ultra-short-acting opioid that is metabolised by non-specific plasma and tissue esterases (Hofmann-independent), giving it a context-sensitive half-time of approximately 3–4 minutes regardless of infusion duration. This makes it ideal for brief procedures requiring rapid opioid offset — patients awaken and recover cognitive function within minutes of discontinuing infusion. Propofol has a short but not ultra-short context-sensitive half-time (~10–15 min for short infusions). Midazolam has a long half-time (1–4 hours). Fentanyl's context-sensitive half-time increases significantly with prolonged infusion (up to 260+ minutes after 8-hour infusion).
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.