Dig deep for that kidney knowledge!  Let’s quickly review: Arginine vasopressin, otherwise known as antidiuretic hormone (ADH), acts on V2 receptors in the renal distal convoluted tubules to concentrate the urine to maintain water homeostasis.  It is implicated in the pathophysiology of hyponatremia, including euvolemic states like SIADH and hypervolemic states like CHF.

So here is tolvaptan, from a class of V2-receptor antagonists that we don’t encounter too often.  Tolvapatan (Samsca®) is FDA-approved, and this trial demonstrates the efficacy of the drug in raising sodium level.

Some things to think about:

• Which patients were studied, and how does this generalize to hospitalized patients you take care of?
• Are the outcome studied clinically relevant?