Hyponatremia induced by oxcarbazepine.

A case of hyponatremia is presented with water intoxication due to treatment with oxcarbazepine (OxCZ). The patient was admitted because of exceeding dullness and increasing seizures. Low values for serum sodium and osmolality were found. Simultaneously with the reduction in OxCZ, values of sodium and osmolality increased, normalizing on discontinuation of the drug, and the exceeding tiredness as well as the generalized seizures disappeared. Low values of arginine-vasopressin were found, suggesting that the mode of action of OxCZ was directly or indirectly at the level of the kidney.