What is the primary treatment for SIADH?

The primary treatment for Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) involves limiting fluid intake, which helps to correct the dilutional hyponatremia characteristic of this condition. Fluid restriction is crucial because the underlying issue in SIADH is the excessive release of antidiuretic hormone (ADH), leading to impaired water excretion and consequent hyponatremia.

Demeclocycline, an antibiotic that acts as an ADH antagonist, may also be utilized, particularly in cases that are resistant to fluid restriction or in chronic SIADH. It works by decreasing the renal response to ADH, thus promoting free water excretion.

In contrast, intravenous hydration is not appropriate in the context of SIADH because it would exacerbate the already present hypervolemia and dilute serum sodium levels further. Antidiuretic hormone itself would not be used therapeutically in SIADH, as it is the excess of this hormone that causes the symptoms. Loop diuretics could theoretically help in specific situations by promoting diuresis; however, they are not the initial line of treatment and may not effectively resolve the hyponatremia as they do not address the underlying mechanism prompting the syndrome