Syndrome of inappropriate antidiuretic hormone secretion possibly associated with amantadine therapy in Parkinson disease.

OBJECTIVES: To report a patient who developed a syndrome of inappropriate antidiuretic hormone secretion (SIADH) related with amantadine therapy. CASE REPORT: A 66-year-old woman, diagnosed with Parkinson disease, developed asthenia, anorexia, weight loss, lethargy and feeling of muscle weakness, and severe hyponatremia, with diagnostic criteria for SIADH, after exposure to amantadine. After amantadine withdrawal, these symptoms disappeared, and sodium levels reached normal values gradually.
CONCLUSIONS: The SIADH should be taken into account among the possible side effects of amantadine.