Seizure Patient on Phenytoin: Diagnostic Considerations

Neuroimaging and Monitoring

• Brain imaging (CT or MRI) should be performed in the emergency department setting when feasible for patients with increased seizure frequency, to exclude new structural lesions, hemorrhage, tumor progression, or other acute pathology, as recommended by the American College of Emergency Physicians 1
• If phenytoin level is subtherapeutic, consider compliance issues, assess for malabsorption or drug interactions, and note that some patients may require higher maintenance doses (200-700 mg/day) to maintain therapeutic levels, according to the American Academy of Neurology 2

Drug Interaction Assessment

• Acute alcohol intake can increase phenytoin levels and cause paradoxical seizures from toxicity, as noted in the Annals of Emergency Medicine 1