[Severe hyponatremia during treatment with fluoxetine].

Serotonin reuptake inhibitors, used as antidepressants, may cause hyponatremia due to a syndrome of inappropriate antidiuretic hormone, specially in elders. Thirty cases with such complication have been reported in the last six years. We report a 76 years old female with a hypertensive cardiopathy and paroxysmal atrial fibrillation treated with amlodipine and sotalol. Five days after starting fluoxetine, the patient presented with a confusional state, gait instability and tremor. Laboratory assessment disclosed a plasma sodium of 115 meq/L. Fluoxetine was discontinued and fluids were restricted. The clinical condition of the patient improved and hyponatremia abated. Hyponatremia must be born in mind as a potential side effect of serotonin reuptake inhibitors.