This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'Which one of the following statements about phenytoin is accurate? \nSelect and explain. \nA. Displaces sulfonamides from plasma proteins, B. Drug of choice in myocionic seizures, C. Half-life is increased if used with phenobarbital, D. Toxicity may occur with only small increments in dose', 'role': 'user'}, {'content': 'Answer: D \nExplanation: high frequency discharges are inhibited with little effect on normal low frequency discharges which allow Na+ channels to recover even when inactivation is prolonged. This effect has been noted at therapeutic concentration of phenytoin, while other effects like reduction in Ca2+ influx, inhibition of glutamate and facilitation of GABA responses have been demonstrated at higher I toxic concentrations. Intracellular accumulation of Na+ that occurs during repetitive firing is prevented. REF KD TRIPATHI 8TH ED.', 'role': 'assistant'}]