**Question:** Cardioselective β-blocker used in glaucoma is

A. Atenolol
B. Bisoprolol
C. Carteolol
D. Timolol

**Core Concept:** Cardioselective β-blockers are a class of medications that primarily target β1 receptors in the heart, sparing β2 receptors in the bronchioles, thereby reducing the risk of heart failure and respiratory complications associated with non-selective β-blockers like Dobutamine.

**Why the Correct Answer is Right:** Dobutamine is a non-selective β-blocker, meaning it blocks both β1 and β2 receptors, resulting in potential respiratory complications like bronchospasm and hypoxia. In contrast, cardioselective β-blockers like Diltiazem, Atenolol, Bisoprolol, and Carteolol have higher affinity for β1 receptors, making them safer for patients with glaucoma while still providing effective control of intraocular pressure.

**Why Each Wrong Option is Incorrect:**

A. Atenolol is a cardioselective β-blocker, but it is not specifically used for glaucoma treatment due to its weak lipophilicity, which reduces its ability to cross the blood-aqueous barrier.

B. Bisoprolol is a cardioselective β-blocker, but it is not commonly used for glaucoma treatment due to its higher affinity for β1 receptors in the heart.

C. Carteolol is a cardioselective β-blocker, but it is not specifically used for glaucoma treatment because it is not effective enough in lowering intraocular pressure.

D. Diltiazem is a calcium channel blocker, not a cardioselective β-blocker, and is not used for glaucoma treatment.

**Clinical Pearl:** In glaucoma management, Diltiazem and Dobutamine are contraindicated due to their non-selective nature. Atenolol is rarely used due to its weak lipophilicity, Bisoprolol is not commonly used due to its higher affinity for β1 receptors in the heart, and Carteolol is not effective enough in lowering intraocular pressure. The correct choice for glaucoma treatment is Diltiazem, a calcium channel blocker, or Dobutamine, a non-selective β-blocker. However, the question is asking for a cardioselective β-blocker, which is used in glaucoma treatment. The correct answer is Diltiazem, a calcium channel blocker, not a cardioselective β-blocker.

**Why Atenolol is not a good choice:**

Atenolol is a cardioselective β-blocker that primarily targets β1 receptors in the heart. Its weak lipophilicity limits its ability to cross the blood-aqueous barrier, which is essential for intraocular pressure reduction in glaucoma treatment.

**Why Bisoprolol is not a good choice:**

Bisoprolol is a cardioselective β-