Drug of choice for Lithium Induced Diabetes Insipidus:
**Core Concept**
Lithium-induced nephrogenic diabetes insipidus (NDI) is a condition where the kidneys are unable to respond to antidiuretic hormone (ADH) due to lithium toxicity, leading to excessive urine production and dehydration.
**Why the Correct Answer is Right**
The drug of choice for lithium-induced NDI is **vasopressin**, which is a synthetic analogue of ADH. Vasopressin works by stimulating the V2 receptors in the renal collecting ducts, increasing water reabsorption and reducing urine output. This helps to alleviate the symptoms of NDI. Other options like thiazide diuretics (e.g., hydrochlorothiazide) and indomethacin are used as adjunctive therapy to enhance the efficacy of vasopressin by reducing urine volume and increasing water reabsorption.
**Why Each Wrong Option is Incorrect**
**Option A:** Desmopressin is a form of vasopressin, but it's not the primary choice for lithium-induced NDI. It's often used in central diabetes insipidus (CDI) due to its longer duration of action.
*Option B:* Hydrochlorothiazide is a thiazide diuretic that can be used as an adjunctive therapy to enhance the efficacy of vasopressin, but it's not the primary treatment for lithium-induced NDI.
*Option C:* Indomethacin is a nonsteroidal anti-inflammatory drug (NSAID) that can be used as an adjunctive therapy to enhance the efficacy of vasopressin, but it's not the primary treatment for lithium-induced NDI.
**Clinical Pearl / High-Yield Fact**
It's essential to note that lithium-induced NDI is a common side effect of long-term lithium therapy, and patients should be monitored regularly for signs of NDI, such as polyuria and polydipsia.
**Correct Answer:** D.