Cardiac monitoring after phenytoin overdose

To evaluate whether patients admitted to the hospital with oral phenytoin overdose should receive cardiac telemetry monitoring.

Retrospective chart review over a 4-year period.

Eastern United States community teaching hospital.

Forty-four patients admitted with a diagnosis of oral phenytoin overdose, with a toxic serum concentration defined as a peak level higher than 20 micrograms/ml, who had electrocardiography performed both at the time of admission and after the phenytoin level had decreased below the toxic threshold.

None.

Chi-square, t test, and Fisher's exact tests were used for analysis. Mean peak phenytoin concentration was 36.7 +/- 12.1 micrograms/ml, with a maximum concentration of 75 micrograms/ml. Electrocardiograms recorded at the time of hospital admission in all 44 cases revealed no clinically significant abnormalities attributable to phenytoin when toxic and posttoxic states were compared. There were no circulatory complications or deaths.

Patients admitted with oral phenytoin overdose with serum concentrations as high as 75 micrograms/ml did not experience any significant cardiovascular arrhythmias or complications. Patients with oral phenytoin overdose do not warrant routine admission to a telemetry bed for management of their condition.