For central diabetes insipidus, what is the first-line pharmacologic treatment?

• A. Desmopressin acetate
• B. Hydrocortisone
• C. Furosemide
• D. Mineralocorticoids

Answer: (A)

Central diabetes insipidus occurs when there is a deficiency of antidiuretic hormone, so the kidneys fail to concentrate urine and produce large volumes of dilute urine. The first-line pharmacologic treatment is desmopressin acetate, a synthetic analog of vasopressin. It acts on the kidney’s V2 receptors in the collecting ducts to promote water reabsorption, which lowers urine volume and increases urine osmolality. This directly substitutes the missing hormone and addresses the underlying problem, making it the most effective initial therapy.

Desmopressin is versatile in administration (intranasal, oral, or injectable) and is started at a low dose and titrated while monitoring the patient’s serum sodium and fluid status to avoid hyponatremia or water intoxication.

Other drugs listed aren’t first-line for central DI because they don’t replace the missing hormone or directly address the inability to concentrate urine: hydrocortisone treats adrenal insufficiency, furosemide is a diuretic used in different DI contexts or conditions, and mineralocorticoids are for mineralocorticoid deficiency or salt-wasting states, not for central DI.