[Hyponatremia of therapeutic origin. Apropos of a case]

Recent epidemiologic studies (11) have shown a frequency of 3-5% of hyponatremia in chronic psychiatric patients, characterized by headaches, blurry vision, weakness, cramps, vomiting and sometimes seizures or coma leading to death. The etiopathology of this electrolytic syndrome is still debated and intriguing. Six to 17% of hospitalized patients in psychiatry present primary polydipsia, among which 25-50% develop hyponatremia. Another cause is the syndrome of inappropriate secretion of anti-diuretic hormone, SIADH, which may be due to a number of psychotropic drugs as carbamazepine, thioridazine, amitriptyline, desipramine, haloperidol, chlorpromazine and fluoxetine (1, 2, 7, 9, 15, 18, 24). These medications can be associated with primary polydipsia but not necessarily, and the hyponatremia is reversible after discontinuiting the treatment. We describe a case of hyponatremia possibly related to clomipramine which has been rarely reported in the literature and discuss the relations between hyponatremia, psychosis, and SIADH.