**Question:** Which of the following drug is contraindicated in glaucoma?

A. Timolol
B. Dorzolamide
C. Brimonidine
D. Latanoprost

**Core Concept:** Contraindications in medicine refer to situations where the use of a particular treatment, in this case, a medication (ophthalmic drops), is not recommended due to potential harm or increased risk for the patient. In the context of glaucoma, it is essential to understand the specific class of drugs and their effects on the eye.

**Why the Correct Answer is Right:** Timolol belongs to the beta-blocker class, which blocks the action of catecholamines (like adrenaline and noradrenaline) on beta receptors. Beta-blockers can cause an increase in IOP (Intraocular Pressure), worsening glaucoma.

**Why Each Wrong Option is Incorrect:**

B. Dorzolamide is a carbonic anhydrase inhibitor that lowers IOP by reducing aqueous humor production. It is considered a safe medication for glaucoma patients.

C. Brimonidine is an alpha-2 agonist that reduces IOP by increasing aqueous humor outflow. It is also considered safe for glaucoma patients.

D. Latanoprost is a prostaglandin F2α analogue that increases aqueous humor outflow, thereby lowering IOP. It is considered a safe medication for glaucoma patients.

**Why Contraindicated Drugs are Wrong:**

A. Timolol: Contraindicated due to potential worsening of IOP, which can exacerbate glaucoma progression.

**Clinical Pearl:** When selecting medications for glaucoma patients, it is crucial to consider the potential impact on intraocular pressure. Selecting medications with proven safety profiles and demonstrated reduction in intraocular pressure is essential to maintain effective glaucoma treatment and minimize the risk of worsening the disease.