Which of the following medications has the HIGHEST increase in context-sensitive half-life during a prolonged infusion?
A. KetamineCorrect Answer: E
The context sensitive half-life is the time required for blood or plasma concentrations of a drug to decrease by 50% after discontinuation of the drug administered by infusion. It factors in the effects of a prolonged infusion on half-life of a drug. In the context of continuous infusions many drugs that are short acting after a single bolus have an increase in their half-life as their volume of distribution becomes saturated. The half-life of fentanyl increases to over 300 minutes after an infusion of 5 hours. The half-life of midazolam increases to between 50 and 75 minutes after an infusion of 5 hours. The half-life of dexmedetomidine increases to around 100 minutes after an infusion of 5 hours. The half-life of propofol and ketamine both increase slightly but are around 25 minutes after an infusion of 5 hours.
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