Abstracts

Rationale: Hyponatremia is a known side effect of some AEDs, especially oxcarbazepine & carbamazepine. It has been reported that levetiracetam in association with carbamazepine increases the risk of hyponatremia. It is not known whether levetiracetam alone lowers serum sodium concentration. Methods: Retrospective case review. We searched our database of patients receiving levetiracetam looking for any change in the serum sodium levels prior to starting levetiracetam and after being on levetiracetam. A list of patients was obtained through the pharmacy database of all the patients who filled / refilled a prescription of levetiracetam over a six month period. Over 120 patients were identified; only those who had serum sodium levels measured within the past six months prior to and at least a week after and within six months of starting levetiracetam were included (44/120+). Patients concomitantly receiving oxcarbazepine or carbamazepine were excluded. Results: There was no significant difference in the serum sodium level before and after starting levetiracetam, tested by 2-tailed t-test. The study had adequate power to be a meaningful negative study. Conclusions: We conclude that hyponatremia is not a usual pharmacologic occurrence with levetiracetam and it is not necessary to monitor serum sodium after starting levetiracetam. Patients who develop hyponatremia while taking oxcarbazepine or carbamazepine can be safely switched to levetiracetam. This does not exclude the possibility of hyponatremia occurring as an idiosyncratic reaction to levetiracetam.