Hello,
Impaired attention and unsteadiness of gait seems to be
phenytoin overdose symptoms. Phenytoin toxicity presents as neurotoxic effects are concentration dependent and can range from mild
nystagmus to ataxia, slurred speech,
vomiting,
lethargy and eventually coma and death.
Paradoxically, at very high concentrations, phenytoin can lead to seizures. The following is a loose correlation of side effects with total plasma phenytoin concentrations:
Less than 10 mg/L: Rare side effects
Ten to 20 mg/L: Occasional mild horizontal nystagmus on lateral gaze
Twenty to 30 mg/L: Nystagmus
Thirty to 40 mg/L: Ataxia, slurred speech, tremor,
nausea, and vomiting
Forty to 50 mg/L: Lethargy, confusion, hyperactivity
Greater than 50 mg/L: Coma and seizures
From the above, examination of her eyes most likely show lateral beating movements of the eyes which is nystagmus.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Pallavi M., Anesthesiologist