Which of the following agents is the drug of choice for Central Diabetes Insipidus –
**Core Concept**
Central Diabetes Insipidus (CDI) is a disorder characterized by the inadequate production of antidiuretic hormone (ADH), also known as vasopressin, leading to excessive thirst and polyuria. The primary goal of treatment is to replace the deficient hormone and restore normal water balance.
**Why the Correct Answer is Right**
The drug of choice for CDI is desmopressin, a synthetic analogue of ADH with a longer duration of action and greater selectivity for the V2 receptor in the renal collecting ducts. This leads to increased water reabsorption and decreased urine production. Desmopressin is administered intranasally or subcutaneously, depending on the severity of the condition.
**Why Each Wrong Option is Incorrect**
**Option A:** Vasopressin is a natural analogue of ADH but has a shorter duration of action and more pronounced vasoconstrictive effects, making it less suitable for long-term treatment of CDI.
**Option B:** Chlorpropamide is an oral antidiabetic drug that can stimulate ADH release but is not a primary treatment for CDI and may have significant side effects.
**Option C:** Hydrochlorothiazide is a thiazide diuretic that can increase sodium and water reabsorption in the distal tubules but is not a replacement for ADH and may worsen symptoms in CDI.
**Clinical Pearl / High-Yield Fact**
Desmopressin is the preferred treatment for CDI due to its efficacy, safety profile, and ease of administration. It's essential to note that CDI can be caused by various conditions, including head trauma, tumors, or infections, and treatment should be tailored to the underlying cause.
**Correct Answer: D. Desmopressin.