Use of Conivaptan for Refractory Syndrome of Inappropriate Secretion of Antidiuretic Hormone in a Pediatric Patient

Abstract

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is the most common form of hyponatremia in hospitalized patients. The available treatment options for SIADH are limited and not completely effective. A more recent and specific option for treatment of hyponatremia secondary to SIADH are the vasopressin-receptor antagonists. Conivaptan, an intravenous vasopressin-receptor antagonist, is Food and Drug Administration approved for the treatment of euvolemic and hypervolemic hyponatremia in adults; however, data regarding its use in pediatric patients are extremely limited. Conivaptan played an integral role in the treatment of hyponatremia in this situation when conventional treatment modalities were ineffective. This patient did not experience any adverse effects, and his sodium level corrected slowly over a 24-hour period, avoiding complications of rapid sodium correction.

Efficiency of Single Dose of Tolvaptan Treatment During the Triphasic Episode After Surgery for Craniopharyngioma

“…Willemsen et al (3) mentioned starting at a low dose to avoid rapid correction of hyponatremia. Furthermore, in another article Peters et al (10) noted the correction of hyponatremia on the first day after conivaptan was given. In our patient, the aqauretic effect of tolvaptan started to emerge about 1 hour after drug ingestion, even though a low dose was used.…”

“…In more severe forms that also show neurological symptoms, administration of hyperosmolar saline combined with furosemide may be required. Additionally, underlying etiology should be treated if possible (3,5,(6)(7)(8)(9)(10). However, these treatments may be inadequate for some patients with SIADH.…”

“…Vaptans are arginine-vasopressin receptor antagonists, thus prevent insertion of aquaporin 2 water channels in the apical membrane promoting reabsorption of water and results in excretion of diluted urine (3,5,11). Tolvaptan is a kind of vaptan and is a selective V2 receptor antagonist, whereas conivaptan is a non-selective V1/V2 receptor antagonist (3,5,6,10). Conivaptan is the US Food and Drug Administration (FDA) approved U n c o r r e c t e d P r o o f for hypervolemic (nephrotic syndrome, cardiac failure and cirrhosis) or euvolemic hyponatremia (SIADH) treatment in adults but not in children (10).…”

“…Tolvaptan is a kind of vaptan and is a selective V2 receptor antagonist, whereas conivaptan is a non-selective V1/V2 receptor antagonist (3,5,6,10). Conivaptan is the US Food and Drug Administration (FDA) approved U n c o r r e c t e d P r o o f for hypervolemic (nephrotic syndrome, cardiac failure and cirrhosis) or euvolemic hyponatremia (SIADH) treatment in adults but not in children (10). Peters et al (10) described the first successful treatment of conivaptan for a pediatric refractory SIADH patient and mentioned that conivaptan played a key role in the management of their case with SIADH and no adverse effects had developed (10).…”

“…Conivaptan is the US Food and Drug Administration (FDA) approved U n c o r r e c t e d P r o o f for hypervolemic (nephrotic syndrome, cardiac failure and cirrhosis) or euvolemic hyponatremia (SIADH) treatment in adults but not in children (10). Peters et al (10) described the first successful treatment of conivaptan for a pediatric refractory SIADH patient and mentioned that conivaptan played a key role in the management of their case with SIADH and no adverse effects had developed (10). Tolvaptan is approved by the FDA since 2009 for adults and successfully used in the treatment of hyponatremia due to SIADH and autosomal dominant polycystic kidney diseases (1,9,11,12).…”