II. Signs
-
Phenytoin level 20 to 30 mcg/ml
- Nystagmus on lateral gaze
- Smooth Extraocular Movements lost
- Sedation
-
Phenytoin level >30 mcg/ml
- Vertical Nystagmus
- Diplopia
- Ataxia or lurching gait
- Coarse extremity Tremor
- Slurred speech
- Altered Level of Consciousness
-
Phenytoin Level >95 mcg/ml
- Lethal (deaths have occurred as low as 50 mcg/ml)
III. Differential Diagnosis
- Posterior fossa tumor
- Acute viral cerebellitis
- Guillain-Barre Syndrome
- Botulism
- Anxiety Disorder
IV. Labs: Serial levels
V. Management
- Manage Hypotension
- Gastric Decontamination
- Treat complete Heart Block
- Treat Seizures
VI. References
- Ellenhorn (1997) Medical Toxicology, p. 605-8
- Katzung (1989) Pharmacology, p. 289-91