Iatrogenic phenytoin toxicity – Newer lessons learnt

Phenytoin is a widely prescribed anti-epileptic drug (AED), but overdoses are common given its narrow therapeutic index. A 24-year-old male, a previously diagnosed case of seizure disorder on multiple AEDs, including phenytoin presented with breakthrough seizures to the medical emergency. The subsequent medical management of this patient led to an inadvertent iatrogenic overdose of phenytoin resulting in encephalopathy in this patient. Given our experience in this patient, we suggest using a newer class of AED for seizure control in a patient already on phenytoin, particularly if immediate therapeutic plasma phenytoin level monitoring is not readily available.