Syndrome of Inappropriate Antidiuretic Hormone Secretion Medication
- Author: Christie P Thomas, MBBS, FRCP, FASN, FAHA; Chief Editor: Vecihi Batuman, MD, FACP, FASN more...
Medication Summary
Vasopressin receptor antagonists inhibit the V2 receptor, reducing the number of aquaporin-2 water channels in the renal collecting duct and decreasing the water permeability of the collecting duct.
The use of a combination of a loop diuretic (eg, furosemide) and the replacement of urine output with a solution that contains a higher Na+ concentration (ie, 3% sodium chloride solution) can be dramatically successful in some patients. Concomitant use of furosemide increases free water excretion relative to Na+ excretion by the kidneys, thus correcting fluid expansion induced by hypertonic sodium chloride solution.
Vasopressin-Related
Class Summary
The potential benefits of these drugs include the predictability of their effect, rapid onset of action, and limited urinary electrolyte excretion. Conivaptan and tolvaptan are currently the only vasopressin receptor antagonists that are commercially available in the United States and FDA-approved for the treatment of euvolemic hyponatremia in hospitalized patients. These medications should be initiated in a closely monitored setting to prevent rapid correction of serum Na+, which can result in central pontine myelinolysis (CMP).[26]
Conivaptan (Vaprisol)
Conivaptan is a parenteral nonselective vasopressin receptor antagonist used for the treatment of euvolemic hyponatremia in hospitalized patients. Conivaptan increases urine output of mostly free water, with little electrolyte loss. It is indicated for hospitalized patients with more severe euvolemic or hypervolemic hyponatremia.
Tolvaptan (Samsca)
Tolvaptan is an oral selective vasopressin V2-receptor antagonist. It is indicated for hypervolemic and euvolemic hyponatremia (ie, serum Na level < 125 mEq/L) or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction. It is used for hyponatremia associated with CHF, liver cirrhosis, and syndrome of inappropriate antidiuretic hormone secretion (SIADH).
Initiate or reinitiate the drug in a hospital environment only since there may be overly rapid correction of the hyponatremia. However, it increases thirst (potentially limiting its effects) and is expensive.
Diuretics, Loop
Class Summary
These agents are often used in the treatment of hypervolemic hyponatremia. In patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) with euvolemic hyponatremia, diuretics are usually used in conjunction with normal saline to replenish the Na+ excreted with the diuresis.
Furosemide (Lasix)
Furosemide increases excretion of water by interfering with the Na+-K+-Cl- (Na-K-2Cl) transporter; that, in turn, results in inhibition of Na+ and Cl- reabsorption in the ascending loop of Henle. Na+ is reabsorbed more distally and the excreted urine is hypo-osmolar in relation to serum.
Diuretics, Osmotic Agents
Class Summary
These agents induce diuresis by elevating the osmolarity of the glomerular filtrate, thereby hindering the tubular reabsorption of water. The overall effect is an increase in free water excretion by the kidneys. Concomitantly, Na+ and Cl- excretion also increase, but to a lesser extent than water excretion.
Urea
Urea is used for the treatment of SIADH refractory to or in patients noncompliant with other therapies or when other therapies are not available. Urea is known to promote diuresis. It decreases brain edema, restores medullary tonicity, and induces Na+ retention. Isosmotic concentration of dextrose or invert sugar is coadministered with urea to prevent hemolysis produced by pure solutions of urea.
Mannitol (Osmitrol)
Mannitol promotes a rapid free-water diuresis by elevating the osmolarity of the glomerular filtrate, thereby hindering the tubular reabsorption of water. Concomitantly, Na+ and Cl- excretion also increase but to a lesser extent than water excretion. It is typically used intravenously, as a 15-20% solution.
Tetracyclines
Class Summary
Demeclocycline is an older tetracycline. One of its adverse effects is nephrogenic diabetes insipidus and polyuria, which can correct the excess of water seen in SIADH. It is no longer available in most countries and may be nephrotoxic in patients with liver failure.
Demeclocycline
Demeclocycline is a tetracycline derivative that induces diabetes insipidus by impairing the generation and action of cAMP, thus interfering with the action of AVP on the collecting duct. The drug's onset of action may be delayed by over a week; thus, it is not indicated for the emergency management of symptomatic hyponatremia.
Verbalis JG, Berl T. Disorders of water balance. In: Brenner BM. Brenner & Rector's The Kidney. Vol 1. 8th ed. Saunders; 2007:459-491.
Elhassan EA, Schrier RW. Hyponatremia: diagnosis, complications, and management including V2 receptor antagonists. Curr Opin Nephrol Hypertens. Mar 2011;20(2):161-8. [Medline].
Kohen I, Voelker S, Manu P. Antipsychotic-induced hyponatremia: case report and literature review. Am J Ther. Sep-Oct 2008;15(5):492-4. [Medline].
Vitting KE, Gardenswartz MH, Zabetakis PM, et al. Frequency of hyponatremia and nonosmolar vasopressin release in the acquired immunodeficiency syndrome. JAMA. Feb 16 1990;263(7):973-8. [Medline].
Hoorn EJ, Lindemans J, Zietse R. Development of severe hyponatraemia in hospitalized patients: treatment-related risk factors and inadequate management. Nephrol Dial Transplant. Jan 2006;21(1):70-6. [Medline].
Schrier RW. Body water homeostasis: clinical disorders of urinary dilution and concentration. J Am Soc Nephrol. Jul 2006;17(7):1820-32. [Medline].
Stelfox HT, Ahmed SB, Khandwala F, Zygun D, Shahpori R, Laupland K. The epidemiology of intensive care unit-acquired hyponatraemia and hypernatraemia in medical-surgical intensive care units. Crit Care. 2008;12(6):R162. [Medline]. [Full Text].
Upadhyay A, Jaber BL, Madias NE. Incidence and prevalence of hyponatremia. Am J Med. Jul 2006;119(7 Suppl 1):S30-5. [Medline].
Ayus JC, Varon J, Arieff AI. Hyponatremia, cerebral edema, and noncardiogenic pulmonary edema in marathon runners. Ann Intern Med. May 2 2000;132(9):711-4. [Medline].
Kumar S, Fowler M, Gonzalez-Toledo E, Jaffe SL. Central pontine myelinolysis, an update. Neurol Res. Apr 2006;28(3):360-6. [Medline].
Ellison DH, Berl T. Clinical practice. The syndrome of inappropriate antidiuresis. N Engl J Med. May 17 2007;356(20):2064-72. [Medline].
Renneboog B, Musch W, Vandemergel X, Manto MU, Decaux G. Mild chronic hyponatremia is associated with falls, unsteadiness, and attention deficits. Am J Med. Jan 2006;119(1):71.e1-8. [Medline].
Clayton JA, Le Jeune IR, Hall IP. Severe hyponatraemia in medical in-patients: aetiology, assessment and outcome. QJM. Aug 2006;99(8):505-11. [Medline].
Decaux G. Is asymptomatic hyponatremia really asymptomatic?. Am J Med. Jul 2006;119(7 Suppl 1):S79-82. [Medline].
Hew-Butler T, Noakes TD, Siegel AJ. Practical management of exercise-associated hyponatremic encephalopathy: the sodium paradox of non-osmotic vasopressin secretion. Clin J Sport Med. Jul 2008;18(4):350-4. [Medline].
Sterns RH, Silver SM. Cerebral salt wasting versus SIADH: what difference?. J Am Soc Nephrol. Feb 2008;19(2):194-6. [Medline].
Yee AH, Burns JD, Wijdicks EF. Cerebral salt wasting: pathophysiology, diagnosis, and treatment. Neurosurg Clin N Am. Apr 2010;21(2):339-52. [Medline].
Tian W, Fu Y, Garcia-Elias A, et al. A loss-of-function nonsynonymous polymorphism in the osmoregulatory TRPV4 gene is associated with human hyponatremia. Proc Natl Acad Sci U S A. Aug 18 2009;106(33):14034-9. [Medline]. [Full Text].
Feldman BJ, Rosenthal SM, Vargas GA, et al. Nephrogenic syndrome of inappropriate antidiuresis. N Engl J Med. May 5 2005;352(18):1884-90. [Medline].
Bartter FC, Schwartz WB. The syndrome of inappropriate secretion of antidiuretic hormone. Am J Med. May 1967;42(5):790-806. [Medline].
Zeltser D, Rosansky S, van Rensburg H, Verbalis JG, Smith N. Assessment of the efficacy and safety of intravenous conivaptan in euvolemic and hypervolemic hyponatremia. Am J Nephrol. 2007;27(5):447-57. [Medline].
Decker BC. Disorders of Water Excess: Hyponatremia. In: Dale DC, Federman DD, eds. ACP Medicine. Vol 1. BC Decker; 2007.
Nemerovski C, Hutchinson DJ. Treatment of hypervolemic or euvolemic hyponatremia associated with heart failure, cirrhosis, or the syndrome of inappropriate antidiuretic hormone with tolvaptan: a clinical review. Clin Ther. Jun 2010;32(6):1015-32. [Medline].
[Best Evidence] Schrier RW, Gross P, Gheorghiade M, Berl T, Verbalis JG, Czerwiec FS, et al. Tolvaptan, a selective oral vasopressin V2-receptor antagonist, for hyponatremia. N Engl J Med. Nov 16 2006;355(20):2099-112. [Medline].
Berl T, Quittnat-Pelletier F, Verbalis JG, et al. Oral tolvaptan is safe and effective in chronic hyponatremia. J Am Soc Nephrol. Apr 2010;21(4):705-12. [Medline]. [Full Text].
Gross P. Treatment of hyponatremia. Intern Med. 2008;47(10):885-91. [Medline].

