What is the primary use of antidiuretic hormone (ADH) antagonists?

The primary use of antidiuretic hormone (ADH) antagonists is to treat conditions like hyponatremia, particularly in patients with heart failure. These medications work by blocking the action of ADH at the renal collecting ducts, leading to increased water excretion without affecting sodium excretion. In cases of heart failure, fluid overload can lead to dilutional hyponatremia, which is a common issue as the body retains excess water in response to low perfusion to the kidneys. By using ADH antagonists, the excess water can be excreted, helping to restore sodium levels and alleviate symptoms associated with fluid overload.

While diuresis in kidney failure is a relevant concern, ADH antagonists are not primarily used for this purpose, as their role is more specific to managing water retention and associated hyponatremia. Additionally, antidiuretic hormone antagonists are not directly indicated for managing edema; rather, they address the underlying problem of water retention that causes hyponatremia. The increase in renal blood flow is not a primary action of ADH antagonists, as these agents mainly focus on altering water balance rather than directly impacting renal hemodynamics.