Drugs for Hyponatremia

Question 1

Conivaptan (given IV)

Answer 1

• nonpeptide ADH receptor antagonist
• promotes excretion of free water
• used for HYPOvolemic and euvolemic hyponatremia
• risk of seizure, osmotic demyelination, coma, and death with too rapid of Na+ correction
• metabolized by CYP3A4

Question 2

tolvaptan (given orally)

Answer 2

• V2 receptor antagonist
• only in hospitalized pts
• can only be used for ≤30 days, or risk of hepatotoxicity
• used to slow progression of adult PKD
• metabolized by CYP3A4

Question 3

desmopressin (DDAVP)

Answer 3

• synthetic analog of ADH
• V2 receptor selective agonist (in contrast to ADH active on V1 and V2)
• decreases urine volume and increases urine osmolality
• used for central diabetes insipidus, and nocturnal enuresis
• risk of hyponatremia, and hypotension