A 17-year-old client is taking phenytoin (Dilantin) for the treatment of seizures. Phenytoin blood level reveals to be 25 mcg/ml. Which of the following symptoms would be expected as a result of the laboratory result?
A. No symptoms, because the value is within the normal range.
B. Hyperactivity.
C. Tremors.
D. Nystagmus.
Correct Answer: D. Nystagmus.
Option D: Phenytoin levels of 20 to 30 mg/L result in nystagmus (Involuntary eye movement).
Option A: The therapeutic level of phenytoin is 10-20mcg/ml. No symptoms will be noted.
Options B & C: Hyperactivity and tremors would occur in phenytoin levels of more than 30 mcg/mL.