Use of intravenous conivaptan in neurosurgical patients with hyponatremia from syndrome of inappropriate antidiuretic hormone secretion.

BACKGROUND: Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of hyponatremia in hospitalized patients and is frequently associated with neurologic disorders and neurosurgical procedures. Traditional therapies such as fluid restriction, sodium repletion, and diuretics can help correct hyponatremia but do not address the underlying pathophysiology of excess arginine vasopressin secretion. Conivaptan is an arginine vasopressin receptor antagonist that has been shown to be both safe and effective in the treatment of euvolemic and hypervolemic hyponatremia.

OBJECTIVE: To analyze the use of conivaptan to treat SIADH in a mixed neurosurgical population.

METHODS: We conducted a retrospective review of 13 patients with neurosurgical disorders with SIADH that were treated with intravenous conivaptan at our institution between 2007 and 2009.

RESULTS: The mean pretreatment serum sodium concentration was 125.8 ± 3.5 mEq/L. Conivaptan administration resulted in a rise in serum sodium to 132.5 ± 5.6 mEq/L at 12 hours (P < .01) and 134.1 ± 4.7 mEq/L at 24 hours posttreatment (P < .01). The mean time to an increase in serum sodium ≥ 6 mEq/L was 17.8 hours. There were no instances of rapid overcorrection. There were 3 cases of asymptomatic hyperkalemia, 3 cases of asymptomatic hypotension, and 1 case of elevated creatinine associated with conivaptan administration.

CONCLUSION: These data provide further support that conivaptan can be safely used for the treatment of SIADH-induced hyponatremia in the neurosurgical arena.