Duloxetine-Induced Hyponatremia in an Elderly Male Patientwith Treatment-Refractory Major Depressive Disorder

Several classes of antidepressants can induce syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH), therebycausing hyponatremia. Initial symptoms of hyponatremia include neuropsychiatric and gastrointestinal manifestations can mimicdepression, especially in elderly people with multiple somatic complaints. Here we present a case of a 68-year-old man withtreatment-refractory depression and general anxiety disorder who developed duloxetine-induced hyponatremia. His symptomsof hyponatremia including unsteady gait, dizziness, nausea, general malaise, and poor appetite subsided after discontinuing theoffending medication. Our case illustrates that drug-induced SIADH and potential drug-drug interactions should be considered inelderly patients who develop hyponatremia following the initiation of antidepressants.