Phenytoin toxicity presents with which symptom?

Phenytoin toxicity presents with which symptom?

• A. Nystagmus
• B. Tremor
• C. Ataxia
• D. Seizures

Answer: (C)

Phenytoin toxicity affects motor coordination because excessive levels disrupt cerebellar function, leading to unsteady, clumsy movements. Ataxia reflects this cerebellar involvement and is a hallmark sign of toxicity. While nystagmus and tremor can occur, ataxia most clearly demonstrates the impaired coordination caused by the drug’s toxic effects. Seizures are not typical of toxicity; they would suggest inadequate control or another issue rather than toxicity itself.

Phenytoin toxicity affects motor coordination because excessive levels disrupt cerebellar function, leading to unsteady, clumsy movements. Ataxia reflects this cerebellar involvement and is a hallmark sign of toxicity. While nystagmus and tremor can occur, ataxia most clearly demonstrates the impaired coordination caused by the drug’s toxic effects. Seizures are not typical of toxicity; they would suggest inadequate control or another issue rather than toxicity itself.