This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
[{'content': 'Phenytoin pharmacokinetics is highlighted by which of the following characteristics? \nSelect and explain. \nA. High first pass metabolism, B. Nonsaturation kinetics of metabolism, C. Capacity limited metabolism saturating at higher therapeutic concentration range, D. Extrahepatic metabolism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (Ref: KDT 6/e p404) Phenytoin follows zero order kinetics at high plasma concentration due to saturation of metabolic pathways.', 'role': 'assistant'}]