Vasopressin receptor antagonists
Arginine vasopressin is the hormone principally responsible for the genesis of most hyponatremic disorders. The persistent inappropriate or maladaptive secretion of this hormone, also known as antidiuretic hormone, prevents excretion of electrolyte-free water leading to water retention and hyponatremia. The vasopressin receptor antagonists, or “vaptans,” are a promising new alternative to the often impractical or ineffective conventional therapies used in many hyponatremic patients currently. The development of vaptans is the culmination of efforts which began more than a century ago. After briefly discussing the vital milestones in the work that led to the introduction of vaptans, this chapter will focus on the major studies that established the specificity, efficacy, and safety of vaptans in the treatment of euvolemic and hypervolemic hyponatremia. We will also review the studies that have shown that the vaptans are not helpful for the primary treatment of chronic heart failure and cirrhosis independent of hyponatremia. Finally, we will discuss the indications and proper use of this new class of drugs, as well as the current impediments to their use and the areas in which further study is needed.
