Which medication is listed as used alongside fluid restriction in the management of antidiuretic hormone dysfunction?

• A. Demeclocycline
• B. Furosemide
• C. Spironolactone
• D. Hydrochlorothiazide

Answer: (A)

In SIADH, too much ADH causes the kidneys to hold water, leading to dilutional hyponatremia. Fluid restriction helps by limiting water intake, but when hyponatremia persists, you add a medication that blunts the kidney’s response to ADH. Demeclocycline does exactly this: it interferes with ADH’s action on the collecting ducts, producing aquaresis (excess water excretion without losing solutes) and helping to raise serum sodium when used with fluid restriction. It’s a classic adjunct in managing antidiuretic hormone dysfunction.

Other diuretics may promote urine production, but they don’t specifically counteract ADH in the collecting ducts, so they’re not the standard paired therapy with fluid restriction for SIADH.