This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Anesthesia, Subject name: Anaesthesia
Which of the following determines the speed of recovery from IV anesthetic? 
Select and explain. 
A. Liver metabolism of drug, B. Protein binding of drug, C. Redistribution of the drug from sites in the CNS, D. Plasma clearance of the drug
C: Redistribution of the drug from sites in the CNS
Answer: C: Redistribution of the drug from sites in the CNS 
Explanation: Ans. c. Redistribution of the drug from sites in the CNSAn IV anesthetic completely bypasses the process of absorption, because the drug is placed directly into the bloodstream. Highly perfused organs (vessel rich) including the brain take up disproportionately large amount of drug compared to less perfused areas (the muscle, fat, and vessel-poor groups).Drugs bound to plasma proteins are unavailable for uptake by an organ.After the highly perfused organs are saturated during initial distribution, the greater mass of the less perfused organs continue to take up drug from the bloodstream.As plasma concentration falls, some drug leaves the highly perfused organs to maintain equilibrium.This redistribution from the vessel-rich group is responsible for termination of effect of many anesthetic drugs.