[Hyponatremia due to psychoactive drugs is common in the elderly].

Hyponatremia due to psychoactive drugs commonly used in the treatment of elderly patients appears usually during the first weeks of treatment. Blood sodium level should be measured before the initiation of medication and checked after a few weeks. Symptoms suggesting hyponatremia in a patient under psychoactive medication are always an indication for checking the sodium level. Restriction of fluid intake to one and a half liters per day may correct mild hyponatremia. First-line treatment is always cessation of drug therapy. If the psychoactive drug is essential for the patient's disease, it will be changed to a different one.