II. Signs

  1. Phenytoin level 20 to 30 mcg/ml
    1. Nystagmus on lateral gaze
    2. Smooth Extraocular Movements lost
    3. Sedation
  2. Phenytoin level >30 mcg/ml
    1. Vertical Nystagmus
    2. Diplopia
    3. Ataxia or lurching gait
    4. Coarse extremity Tremor
    5. Slurred speech
    6. Altered Level of Consciousness
  3. Phenytoin Level >95 mcg/ml
    1. Lethal (deaths have occurred as low as 50 mcg/ml)

III. Differential Diagnosis

  1. Posterior fossa tumor
  2. Acute viral cerebellitis
  3. Guillain-Barre Syndrome
  4. Botulism
  5. Anxiety Disorder

V. Management

  1. Manage Hypotension
  2. Gastric Decontamination
  3. Treat complete Heart Block
    1. Atropine
    2. Pacemaker
  4. Treat Seizures
    1. Diazepam 0.1 to 0.3 mg/kg IV to 20 mg/dose
    2. May repeat Diazepam dosing in 20 minutes

VI. References

  1. Ellenhorn (1997) Medical Toxicology, p. 605-8
  2. Katzung (1989) Pharmacology, p. 289-91

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Ontology: PHENYTOIN TOXICITY (C0149969)

Concepts Injury or Poisoning (T037)
English PHENYTOIN TOXICITY