Non-selective beta blocker used in glaucoma:
Non-selective beta blockers block both beta-1 and beta-2 receptors. In the eye, they reduce aqueous humor production. The main ones I remember are timolol and betaxolol. Wait, betaxolol is selective for beta-1, so that's a selective one. So the non-selective ones would be timolol, carteolol, maybe metipranolol. Let me check. Timolol is definitely non-selective. So the correct answer is likely timolol.
Now the options. If the options include timolol, that's the answer. The other options might be other beta blockers. Let's see. Option B could be betaxolol, which is selective. Option C might be metoprolol, which is a beta-1 selective blocker used in hypertension. Option D could be propranolol, another non-selective beta blocker but more systemic use. But in glaucoma, timolol is the standard. So the correct answer is A, B, C, or D depending on the options given. Wait, the user didn't provide the options, so I need to assume. Let's say the options are: A. Timolol, B. Betaxolol, C. Metoprolol, D. Propranolol. Then the correct answer is A. Timolol.
Why the others are wrong: Betaxolol is selective. Metoprolol is a beta-1 blocker, so selective. Propranolol is non-selective but more systemic use. Clinical pearl: Timolol is the most common non-selective beta blocker used in glaucoma. Always check if beta blocker is selective or not. Avoid in asthmatics because of beta-2 blockade.
**Core Concept**
Non-selective beta blockers inhibit both β1 and β2 adrenergic receptors. In glaucoma, they reduce aqueous humor production by decreasing ciliary epithelial secretion, lowering intraocular pressure (IOP).
**Why the Correct Answer is Right**
Timolol is a non-selective beta blocker (blocks β1 and β2 receptors) used topically in glaucoma. It reduces aqueous humor synthesis via ciliary body action. Its non-selective profile is critical for efficacy, though systemic absorption risks bronchospasm in asthmatics.
**Why Each Wrong Option is Incorrect**
**Option B:** Betaxolol is a *selective* β1 blocker used in glaucoma but lacks β2 blockade.
**Option C:** Metoprolol is a β1-selective blocker used for hypertension/arrhythmias, not glaucoma.
**Option D:** Propranolol is non-selective but systemic (oral), not topical, and reserved for systemic conditions like hypertension.
**Clinical Pearl / High-Yield Fact**
Timolol is the prototypical non-selective beta blocker for glaucoma. Avoid in patients with asthma/COPD due to β2 blockade. Always confirm beta blocker select