FDA Approves Samsca

Last week, the FDA approved Samsca (tolvaptan) for the treatment of hyponatremia (or low blood sodium levels). The topic of hyponatremia often confuses medical students because of the complex physiology involved in sodium regulation. You have hormones like ADH (antidiuretic hormone) affecting the kidney. Then you may get patients with mental illness who may also have primary (or psychogenic) polydipsia. These individuals drink so much water that their blood sodium level gets dangerously low.

Samsca is approved to treat hyponatremia associated with congestive heart failure, liver cirrhosis, and the syndrome of inappropriate antidiuretic hormone secretion (SIADH). What's also interesting is that the FDA is requiring a Risk Evaluation and Mitigation Strategy (REMS) that requires a patient Medication Guide be given out when the drug is dispensed. Why? Because Samsca comes with a boxed warning about the possibility of osmotic demyelination syndrome (ODS). Samsca is marketed by Otsuka Pharmaceuticals Co. Ltd., Tokyo, Japan.