**Core Concept**
α2 agonists, such as clonidine and dexmedetomidine, act primarily on central α2 receptors in the brainstem to reduce sympathetic outflow. This leads to decreased blood pressure, sedation, and reduced anxiety. Peripheral α2 receptors also mediate vasoconstriction and are involved in conditions like glaucoma and hypertension.

**Why the Correct Answer is Right**
Clonidine and other α2 agonists reduce sympathetic tone by stimulating presynaptic α2 receptors in the brainstem, resulting in decreased norepinephrine release. This causes **sedation** (A), **lowered intraocular pressure** in glaucoma (B), and **reduced blood pressure** in hypertension (D). However, they are **not used** for benign prostatic hyperplasia (BPH) because α2 agonists cause **vasoconstriction** and **increased bladder outlet resistance**, which can worsen urinary retention and are not beneficial in BPH management.

**Why Each Wrong Option is Incorrect**
Option A: α2 agonists produce central sedation via inhibition of noradrenergic transmission in the locus coeruleus.
Option B: In glaucoma, α2 agonists reduce aqueous humor production in the ciliary body, lowering intraocular pressure.
Option D: α2 agonists lower blood pressure by reducing sympathetic tone, making them useful in hypertension.

**Clinical Pearl / High-Yield Fact**
α2 agonists are contraindicated in patients with obstructive uropathy or BPH due to potential worsening of urinary retention. Always remember: **α2 agonists are not used for benign prostatic hyperplasia** — this is a classic exam trap.

✓ Correct Answer: C. Benign hyperplasia of prostate