RESUMO
The notable incidence of epilepsy in the general population, with the presence, more and more frequent of refractory therapeutic, it forces the anticonvulsant polytherapy. If we depart from the fact, that many of the epilepsies have a secondary cause, with affective disorders associate, we can understand the most habitual association of anticonvulsant and antidepressant. We present the clinical case of a 37-year-old-woman with refractory therapeutic epilepsy associated to exogenous depressive syndrome, in combined treatment with Carbamazepine, Lamotrigine and Venlafaxine, that suffers a episode of syncope secondary to symptomatic hyponatraemia, generated by syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The relevance of this case resides in the fact that the hyponatraemia generated by this pharmacological combination, up to now, it has not been described in the literature. This electrolytic anomaly can derive in secondary neurological and cardiovascular effects, in so outstanding occasions, as to produce the phenomenon denominated sudden death in the epileptic patient (SUDEP). We recommended a strict ionic control in those patients that require anti-epileptic and anti-depressant treatment combined, in order to avoiding paroxistic vascular episodes and to minimize the risk of SUDEP.