Drug of choice for open angle glaucoma –
**Question:** Drug of choice for open angle glaucoma -
A. Timolol
B. Latanoprost
C. Brimonidine
D. Dorzolamide
**Core Concept:**
Open angle glaucoma is a chronic eye disease characterized by elevated intraocular pressure resulting in progressive optic nerve damage and vision loss. Treatment aims to lower intraocular pressure (IOP) and preserve vision.
**Why the Correct Answer is Right:**
The correct answer, B. Latanoprost, is a prostaglandin analogue and a carbonic anhydrase inhibitor. Prostaglandin analogues like Latanoprost act as prostaglandin F2 alpha (PGF2alpha) analogues, stimulating the production of aqueous humor and increasing outflow resistance. Carbonic anhydrase inhibitors such as Dorzolamide work by inhibiting the carbonic anhydrase enzyme in the ciliary body, leading to a decrease in aqueous humor production and reduced IOP.
**Why Each Wrong Option is Incorrect:**
A. Timolol is a beta-blocker that blocks beta receptors in the eye, reducing aqueous humor production and decreasing IOP. However, it lacks the combined effect of prostaglandin analogues and carbonic anhydrase inhibitors (Option B), which makes it less effective in lowering IOP.
C. Brimonidine is a selective alpha-2 adrenergic receptor agonist that reduces aqueous humor production by inhibiting the sympathetic nervous system. While it is effective in reducing IOP, it lacks the additional effect of carbonic anhydrase inhibition (Option B), reducing its overall efficacy in lowering IOP.
D. Dorzolamide is a carbonic anhydrase inhibitor that inhibits the carbonic anhydrase enzyme in the ciliary body, decreasing aqueous humor production and lowering IOP. However, it does not have the additional effect of prostaglandin analogues (Option B), which enhances its effectiveness in reducing IOP.
**Clinical Pearl:**
Multiple medications can be used to manage open angle glaucoma, but combining prostaglandin analogues and carbonic anhydrase inhibitors (Option B) provides a more comprehensive and effective approach in reducing IOP and preventing vision loss due to glaucoma.