HYPONATREMIA IN OLANZAPINE TREATED PATIENT

Abstract

Hyponatremia is sodium level imbalance, defined as levels below 135 mmol/l. Numerous factors may lie in its etiology and pathogenesis including psychotropic drug use, and in such cases hyponatremia is an adverse event. The syndrome of inappropriate secretion of antidiuretic hormone secretion (SIADH) has been reported with the use of antidepressants, antipsychotics and mood stabilizers. The exact pathophysiological mechanisms for this syndrome are still in the process of investigation. The findings so far indicate: increased secretion of ADH from hypothalamus as a result of dopamine-D2 receptor inhibition (suppression of the inhibitory effect of dopamine on ADH secretion), as well as the effect of 5-HT2 and 5-HT1C serotonin receptors which also leads to an increase in ADH levels and potentiation of its effect at the renal level. Having seen similar symptoms in SIADH and in psychiatric entities, it can cause hyponatremia to remain unrecognized in clinical practice, especially if mild and if it develops slowly. However, in some cases it may progress to severe hyponatremia which becomes an urgent condition. On the other hand, if recognized and treated in time, there is a satisfactory outcome. We report a case-report of 64-year-old woman who has been treated for a schizophrenia disorder for thirty years with good remission of symptoms by regular use of antipsychotics (orally and in depot form). The current deterioration occurred in the last five months, due to non-compliance to the treatment. During treatment hyponatremia was induced by the second generation of antipsychotic drug. In conclusion we recommend for clinicians not only to be cautious when prescribing psychotropic drugs, and to assess sodium laboratory values and clinical symptoms for all patients after initiation of antipsychotic drug as a routine clinical practice, but also to take into account differential diagnoses for presented symptoms