**Question:** Drug of choice in nocturnal enuresis is

A. Desmopressin
B. Mefenamic acid
C. Tranexamic acid
D. Doxazosin

**Correct Answer:** A. Desmopressin

**Core Concept:**
Nocturnal enuresis, also known as bedwetting, is the involuntary urination during sleep in children who are normally continent during the day. It is a common issue in pediatric urology and can have psychological and social impacts on the child and family. Treatment options for nocturnal enuresis include behavioral therapy, alarm therapy, and pharmacotherapy.

**Why the Correct Answer is Right:**
Desmopressin is a synthetic analogue of antidiuretic hormone (ADH) that acts on the kidneys to increase urine osmolality and reduce urine production, leading to a decrease in nocturnal urine output. It is highly selective for the V2 receptors in the kidneys, making it a more specific and less nephrotoxic alternative to antidiuretic hormone itself.

**Why Each Wrong Option is Incorrect:**

B. Mefenamic acid (nonsteroidal anti-inflammatory drug) is primarily used to reduce pain and inflammation but has no specific effect on urinary system function or nocturnal enuresis. It is not a first-line choice for this condition.

C. Tranexamic acid (an antifibrinolytic drug) is primarily used to reduce bleeding and prevent blood clot formation. It does not directly target the urinary system or nocturnal enuresis.

D. Doxazosin (alpha-blocker) is primarily used for the treatment of hypertension and benign prostatic hyperplasia (BPH). It is not targeted for nocturnal enuresis, as it primarily affects alpha1-adrenergic receptors in the bladder, prostate, and smooth muscle, not specifically the urinary system or nocturnal enuresis.

**Clinical Pearl:**
Desmopressin is a safer and more effective alternative to antidiuretic hormone in treating nocturnal enuresis. In clinical practice, it is the first-line choice for treating nocturnal enuresis due to its specificity for the urinary system and its reduced risk of nephrotoxicity compared to antidiuretic hormone.