Hyponatremia with consciousness disturbance associated with esomeprazole

LETTERS AND COMMENTS

Hyponatremia with consciousness disturbance associated with esomeprazole TO THE EDITOR: Hyponatremia is a rarely reported adverse drug reaction (ADR) associated with proton pump inhibitors (PPIs). As of this writing, we report the first case of severe hyponatremia associated with esomeprazole administration.

Conclusions. The relationship between hyponatremia and esomeprazole therapy cannot be explained by cross-reactivity between PPIs because the patient had not developed hyponatremia while taking lansoprazole. Hyponatremia may rarely be associated with PPIs, but clinicians should be aware of this possible adverse reaction.

Case Report. On August 15, 2002, an 81-year-old white woman was hospitalized with unusual lethargy. Her past medical history revealed concentric cardiomyopathy secondary to hypertension, stabilized for the past 2 years by spironolactone 75 mg daily, and a recurring gastroesophageal reflux requiring maintenance therapy with lansoprazole for the past 3 years. Routine blood testing had shown normal sodium levels of 134 mEq/L one month before her admission. On August 10, 2002, lansoprazole was replaced by esomeprazole 20 mg daily. Subsequently, the woman started to complain of asthenia and consciousness disturbance, requiring her to be hospitalized. Physical examination on admission showed BP 130/65 mm Hg without orthostatic hypotension, HR 70 beats/min with regular rhythm, and T 36.9 ˚C. There were no abnormal findings in the chest, abdomen, or extremities. There were no signs of dehydration or edema. The neurologic examination confirmed a consciousness disturbance without any other neurologic disorder. Blood chemistry showed hyponatremia (sodium 122 mEq/L). Other blood chemistry parameters were within normal ranges. There were no abnormal findings in brain computed tomography scan, chest X-ray, and electrocardiogram. Plasma and urinary osmolality were 275 mOsm/kgH2O (reference range 280–310) and 351 mOsm/L (reference range 50–1400), respectively, with natriuresis of 80 mmol/24h. Plasma antidiuretic hormone (ADH) was 1.8 mmol/L (reference range