Drug of choice for central diabetes insipidus –
**Core Concept**
Central diabetes insipidus (CDI) is a rare condition characterized by the inadequate production of antidiuretic hormone (ADH), also known as vasopressin, by the posterior pituitary gland. This hormone plays a crucial role in regulating water reabsorption in the kidneys, and its deficiency leads to excessive thirst and polyuria.
**Why the Correct Answer is Right**
The drug of choice for central diabetes insipidus is desmopressin, a synthetic analogue of ADH. Desmopressin works by mimicking the action of natural ADH, promoting water reabsorption in the collecting ducts of the kidneys, and thereby reducing urine production. It has a longer duration of action and a more selective effect on V2 receptors, which are responsible for water reabsorption, compared to natural ADH.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because vasopressin, while related to ADH, is more of a pressor agent and has a shorter duration of action. It is not the preferred treatment for CDI.
**Option B:** This option is incorrect because chlorpropamide, a sulfonylurea, is actually used to treat diabetes mellitus type 2 and has a side effect of inducing ADH release, but it is not the primary treatment for CDI.
**Option C:** This option is incorrect because hydrocortisone, a glucocorticoid, is used to treat adrenal insufficiency, not CDI.
**Clinical Pearl / High-Yield Fact**
Desmopressin is a high-yield fact because it is the preferred treatment for central diabetes insipidus due to its selective action on V2 receptors and longer duration of action, making it more effective in reducing polyuria.
**Correct Answer:** D. Desmopressin