Seizure Disorders USMLE Step 1 Practice Question
A 45-year-old man with a 3-year history of poorly controlled temporal lobe epilepsy on phenytoin monotherapy presents with new-onset ataxia, tremor, and gum hyperplasia. His last seizure was 6 months ago. Serum phenytoin level is 35 mcg/mL (therapeutic range: 10-20 mcg/mL). Which of the following is the most appropriate next step?
Answer choices
- AIncrease phenytoin dose to maximize seizure control
- BAdd valproic acid to achieve seizure control
- CReduce phenytoin dose and consider alternative antiepileptic drugCorrect answer
- DMaintain current dose and add a benzodiazepine
- EDiscontinue phenytoin abruptly to prevent chronic toxicity
- FCheck phenytoin metabolism with cytochrome P450 testing and adjust dosing based on genetic polymorphisms
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