title: Use of conivaptan for management of hyponatremia following surgery for Cushing's disease.
abstract: BACKGROUND
  Hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common osmoregulatory complication following surgery for Cushing's disease. Conventional management includes water restriction and sodium repletion, however this regimen does not address the underlying pathophysiology of excessive vasopressin production. Vaptans are arginine vasopressin receptor antagonists shown to be effective in correcting water excess in other disease states of euvolemic and hypervolemic hyponatremia. The use of these agents has not been reported in Cushing's patients.
  
  
  METHODS
  We retrospectively studied Cushing's patients at our institution with post-surgical hyponatremia (Na<130mEq/L) treated with and without conivaptan between 2005 and 2011. We report rates of serum sodium normalization and compare length-of-stay (LOS) between the groups.
  
  
  RESULTS
  Hyponatremia developed in six of 98 patients (6.1%) undergoing resection of ACTH-positive pituitary adenomas. Three patients received conivaptan and fluid restriction±sodium supplementation, and three received conventional therapy alone. The rate of serum sodium normalization with conivaptan was 5.8±2.3mEq/L/20mg IV bolus given every 24h. All patients receiving conivaptan were discharged with normal serum sodium values and no instances of rapid overcorrection occurred. A trend toward longer LOS occurred in patients treated with conivaptan (4.6±0.3 days, mean±SE) versus conventional therapy alone (1.6±0.3 days).
  
  
  CONCLUSIONS
  Conivaptan is a potentially useful treatment option for hyponatremia in the setting of Cushing's disease patients after pituitary surgery.
authors.affiliation: California Center for Pituitary Disorders, Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA. Electronic address: breshearsj@neurosurg.ucsf.edu.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Breshears
authors.forename: Bowen
authors.initials: B
authors.lastname: Jiang
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Rowland
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kunwar
authors.forename: Lewis S
authors.initials: LS
authors.lastname: Blevins
mesh_terms: D000328:Adult; D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines / Q000008:administration & dosage / Q000627:therapeutic use*; D003480:Cushing Syndrome / Q000150:complications / Q000188:drug therapy* / Q000601:surgery; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000188:drug therapy* / Q000209:etiology; D007177:Inappropriate ADH Syndrome / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000150:complications / Q000601:surgery; D012189:Retrospective Studies; D012964:Sodium / Q000378:metabolism; D014868:Water Deprivation / Q000502:physiology
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; C106389:conivaptan; D012964:Sodium
keywords: ACTH-secreting pituitary adenoma; Conivaptan; Cushing's disease; Hyponatremia; SIADH