In SIADH, which therapies may be used in select cases?

• A. Loop diuretics alone
• B. Hypertonic saline as first-line therapy
• C. Vasopressin receptor antagonists (vaptans) or demeclocycline
• D. Free water restriction only

Answer: (C)

Treating SIADH centers on counteracting excessive water retention so sodium can rise safely. Beyond fluid restriction, there are targeted options that may be used in select cases.

Vasopressin receptor antagonists block the kidney’s ADH receptors, promoting free-water excretion without大量 salt loss. This aquaresis helps raise serum sodium more predictably when fluid restriction alone isn’t enough, but it requires careful monitoring to avoid too-rapid correction and other safety concerns.

Demeclocycline works differently by dampening the kidney’s response to ADH, effectively inducing a state of nephrogenic diabetes insipidus that increases free-water excretion. It’s an older option and carries risks like nephrotoxicity and photosensitivity, so it’s reserved for specific situations where other approaches aren’t suitable.

These therapies aren’t first-line for all SIADH cases; they’re considered when standard measures (like fluid restriction) aren’t sufficient or feasible. Hypertonic saline is generally reserved for severe symptoms, and using loop diuretics alone isn’t the preferred strategy.