Incidence of hyponatremia in patients given levetiracetam vs. phenytoin for early posttraumatic seizure prophylaxis

Background: Levetiracetam and phenytoin are comparable for acute posttraumatic seizure(PTS) prophylaxis. Levetiracetam-induced hyponatremia has been reported in non-trauma patients. We studied hyponatremia in posttraumatic intracranial hemorrhage(ICH) patients receiving either drug.

Methods: Retrospective review of patients with ICH receiving PTS prophylaxis was performed. Patients were categorized by degree of sodium nadir: normal, mild, moderate, or severe, and analyzed by levetiracetam versus phenytoin. Patients were matched 2:1 regarding age and injury severity score(ISS). Incidence and treatment for hyponatremia was examined.

Results: 1735 ICH patients received PTS prophylaxis over an 8-year period. After exclusions and matching, there were 282 phenytoin and 564 levetiracetam patients. Age, ISS and initial sodium were comparable between the matched cohorts. There was no clinically significant difference in the rate or degree of hyponatremia. Treatment was more common in levetiracetam patients.

Discussion: There was a small but clinically insignificant difference in the incidence of hyponatremia in traumatic ICH patients receiving levetiracetam vs. phenytoin for PTS prophylaxis. There was an increased rate of intervention for hyponatremia in the levetiracetam group, possibly due to a coincidental preventive paradigm shift.

Keywords: Hyponatremia; Levetiracetam; Phenytoin; Traumatic brain injury.