Acute poisoning with phenytoin caused by an error in the administration of fosphenytoin (Prodilantin)

Following surgery for a chronic subdural haematoma, a 74-year-old patient received fosphenytoin as prophylaxis for epilepsy. The patient received 10 times the prescribed dose. This error in the administration of fosphenytoine was facilitated by a confusing labeling of the product. The phenytoin blood level was 79 micrograms.mL-1. The main adverse effect was a coma requiring 5 days of mechanical ventilation. No adverse cardiovascular event was noted. The phenytoin blood levels returned toward the therapeutic range in 8 days. At discharge from the hospital 20 days after surgery, the patient did not have any sequela from the fosphenytoin intoxication.