Experience with Tolvaptan for Euvolemic and Hypervolemic Hyponatremia in the Acute Care Setting

Hyponatremia is a common electrolyte disorder and is associated with multiple comorbidities. Management strategies are varied and etiology-dependent. The use of tolvaptan, a vasopressin antagonist, outside of clinical trials has not been well characterized.

To quantify tolvaptan compliance with institutional guidelines and make recommendations concerning reasonable expectations for its role in hyponatremia management.

This was a retrospective observational study in a 125-bed community hospital. Patients admitted in 2013 who received at least one dose of tolvaptan were included.

Thirty-seven patient encounters were evaluated. Tolvaptan was prescribed with 83.7% adherence to the institutional order set. Mean age was 71 ± 16.4 years with 20 (54%) females. Hyponatremia was a contributory cause of admission in 15 (40.5%) patients and offending medications were discontinued in 7 (19%). Causes of hyponatremia included syndrome of inappropriate antidiuretic hormone (SIADH), heart failure, and cirrhosis in 78.3%, 8.2%, and 13.5% of participants, respectively. Management included fluid restriction in 19 (51%) and furosemide in 5 (13.5%), with tolvaptan administration on average 3.2 days after admission. Most patients (78.4%) required ≤2 doses. Sodium concentration was elevated 8 mEq/L by the end of hospitalization. Discharge to palliative care or death occurred in 8 (21.6%). Postdischarge review revealed 3 (8%) maintained sodium concentration ≥130 mEq/dL.

Tolvaptan was initiated after other interventions and with limited duration per institutional guidelines. This cohort had complicating underlying chronic diseases. These results will be used to refine recommendations with pharmacist input for risk/benefit stratification based on reasonable expectations.