Phenytoin toxicity: a review of 94 cases

Records of all patients admitted to an urban teaching hospital from 1977-1987 with a diagnosis of phenytoin toxicity were reviewed in order to determine indications for admission and discharge, and to assess the need for therapeutic intervention and monitoring. Of 94 patients identified, 57 were male and 37 were female. Ages ranged from 19 mo to 84 yr. Serum phenytoin levels ranged from 21.4-90 micrograms/ml, with a mean level 44.4 +/- 12.5 micrograms/ml. Ataxia was observed in 59/94 patients (63%), and of these 18 patients had fallen; 9 had suffered injury from falling sufficient to require medical care. No other factors were associated with morbidity. No hemodynamic instability was seen in any of the cases. Electrocardiographic records were available for 71/94 cases (76%). There were no abnormalities due to phenytoin. Symptoms of toxicity resolved with supportive care. There were no deaths in this series. Phenytoin is a relatively safe medication even in the toxic range as determined by baseline phenytoin levels. Hospital admission is indicated in symptomatic cases until a declining serum phenytoin level is observed and ataxia resolves. The data in this series do not support routine electrocardiographic monitoring in cases of phenytoin toxicity.