Ophthalmic Pharmacology

Ophthalmic Pharmacology Indian Medical PG Question 1: In the treatment of superficial bacterial skin infections, what is the standard concentration of tetracycline ointment typically prescribed for topical application?

• A. 0.10%
• B. 0.50%
• C. 5%
• D. 1% (Correct Answer)

Ophthalmic Pharmacology Explanation: ***1%*** - **Tetracycline 1% ointment** is the standard and effective concentration for topical application in superficial bacterial skin infections [1]. - This concentration ensures adequate therapeutic levels of the antibiotic at the site of infection while minimizing systemic absorption. *0.10%* - A concentration of **0.10% tetracycline** is generally too low to be effective against most common bacterial skin infections. - This insufficient concentration could lead to treatment failure and potentially contribute to antibiotic resistance. *0.50%* - While higher than 0.10%, **0.50% tetracycline** is still considered a suboptimal concentration for treating superficial bacterial skin infections. - It might not achieve the necessary bactericidal or bacteriostatic effects required for successful eradication of the infection. *5%* - A **5% concentration of tetracycline** is typically too high for topical application and could increase the risk of local irritation or sensitization. - While potentially more potent, it is not the standard and usually offers no significant therapeutic advantage over the 1% concentration for superficial infections, while increasing potential side effects.

Ophthalmic Pharmacology Indian Medical PG Question 2: Which of the following is a contraindication to topical steroids?

• A. Dendritic ulcer (Correct Answer)
• B. Herpetic stromal keratitis without epithelial defect
• C. Elevated intraocular pressure
• D. Non-infectious anterior uveitis

Ophthalmic Pharmacology Explanation: ***Dendritic ulcer*** - A **dendritic ulcer** is characteristic of **herpes simplex keratitis**, which is an active viral infection of the cornea. - **Topical steroids** are contraindicated because they can suppress the immune response, leading to viral replication, corneal melt, and potentially severe vision loss or perforation. *Herpetic stromal keratitis without epithelial defect* - In cases of **stromal keratitis**, where the infection is deeper and an intact epithelium is present, topical steroids may be used cautiously in conjunction with antiviral agents to reduce inflammation and scarring. - The primary concern with steroids in herpes simplex keratitis is activating viral replication in the presence of an **epithelial defect**, which is not present here. *Elevated intraocular pressure* - **Elevated intraocular pressure** is a known side effect of topical steroid use, especially with prolonged administration, but it is not an absolute contraindication in itself. - It necessitates careful monitoring and may require concurrent glaucoma treatment, but the primary condition needing steroids may still warrant their use. *Non-infectious anterior uveitis* - **Topical corticosteroids** are the **mainstay of treatment** for non-infectious anterior uveitis to reduce inflammation and prevent complications such as synechiae and vision loss. - The benefits of controlling inflammation in uveitis generally outweigh the risks associated with judicious steroid use.

Ophthalmic Pharmacology Indian Medical PG Question 3: All are drugs which lower IOP except:

• A. Mannitol
• B. Clonidine
• C. Acetazolamide
• D. Dexamethasone (Correct Answer)

Ophthalmic Pharmacology Explanation: ***Dexamethasone*** - Dexamethasone is a **corticosteroid** that is known to increase **intraocular pressure (IOP)**, particularly with prolonged use, in susceptible individuals. - This increase in IOP is a significant side effect and can lead to **steroid-induced glaucoma**. *Mannitol* - **Mannitol** is an osmotic diuretic that rapidly reduces IOP by creating an osmotic gradient, drawing water out of the eye. - It is often used in acute settings for rapid reduction of **high IOP**, such as in acute angle-closure glaucoma. *Clonidine* - **Clonidine** is an alpha-2 adrenergic agonist that lowers IOP by reducing aqueous humor production and possibly increasing uveoscleral outflow. - While not a primary glaucoma medication, it has been shown to have an **IOP-lowering effect**. *Acetazolamide* - **Acetazolamide** is a carbonic anhydrase inhibitor that significantly reduces IOP by decreasing the production of aqueous humor. - It is a cornerstone medication for managing **glaucoma** and other conditions requiring IOP reduction.

Ophthalmic Pharmacology Indian Medical PG Question 4: The α2 agonist used in glaucoma is:

• A. Brimonidine (Correct Answer)
• B. Guanabenz
• C. Guanfacine
• D. Tizanidine

Ophthalmic Pharmacology Explanation: ***Correct: Brimonidine*** - **Brimonidine** is an **α2-adrenergic agonist** commonly used in the treatment of glaucoma - It works by reducing **aqueous humor production** and increasing **uveoscleral outflow**, thereby lowering intraocular pressure - Available as eye drops (0.1%, 0.15%, 0.2% concentrations) *Incorrect: Guanfacine* - **Guanfacine** is an **α2A-adrenergic agonist** primarily used to treat **attention deficit hyperactivity disorder (ADHD)** and **hypertension** - It does not have a primary role in glaucoma treatment *Incorrect: Guanabenz* - **Guanabenz** is an **α2-adrenergic agonist** that acts centrally to reduce **sympathetic outflow**, used mainly as an **antihypertensive agent** - It is not indicated for the treatment of glaucoma *Incorrect: Tizanidine* - **Tizanidine** is an **α2-adrenergic agonist** primarily used as a **muscle relaxant** to manage spasticity - It is not used for glaucoma

Ophthalmic Pharmacology Indian Medical PG Question 5: Carbonic anhydrase inhibitor should not be given in:

• A. Epilepsy
• B. High altitude sickness
• C. Sulfonamide hypersensitivity (Correct Answer)
• D. Glaucoma

Ophthalmic Pharmacology Explanation: ***Sulfonamide hypersensitivity*** - Carbonic anhydrase inhibitors (CAIs) are **sulfonamide derivatives**, so they are absolutely contraindicated in patients with a history of **sulfonamide allergy**. - Administration to such patients can lead to severe **hypersensitivity reactions**, including rash, fever, and even anaphylaxis. *Epilepsy* - **Acetazolamide**, a carbonic anhydrase inhibitor, can be used as an **adjunct therapy for certain types of epilepsy**, such as absence seizures. - It works by reducing neuronal excitability through its effects on pH, thus it is not contraindicated but rather sometimes indicated. *High altitude sickness* - Carbonic anhydrase inhibitors like **acetazolamide** are commonly used to **prevent and treat high altitude cerebral and pulmonary edema** by inducing metabolic acidosis and stimulating respiration. - This is a recognized therapeutic indication, not a contraindication. *Glaucoma* - CAIs are a **primary treatment for glaucoma** (both open-angle and angle-closure) because they reduce the production of aqueous humor, thereby lowering intraocular pressure. - They are used both systemically and topically for this purpose, making it an indication, not a contraindication.

Ophthalmic Pharmacology Flashcard 1 of 5

Question: What drugs are used for the mainstay of treatment for uveitis?_____

Answer: Steroids and cycloplegics

Ophthalmic Pharmacology Flashcard 2 of 5

Question: Latanoprost and bimatoprost can produce _____ pigmentation in the iris and can cause eyelash growth

Answer: brown

Ophthalmic Pharmacology Flashcard 3 of 5

Question: Netarsudil is associated with the development of _____

Answer: vortex keratopathy::Corneal pathology

Ophthalmic Pharmacology Flashcard 4 of 5

Question: _____ dye stains dead and degenerate cells, but does not stain healthy epithelial cells, and is used to diagnose ocular surface disease

Answer: Lissamine green

Ophthalmic Pharmacology Flashcard 5 of 5

Question: What is the use of Atropine for uveitis?_____

Answer: relives spasm, prevents synechiae formation and reduces exudation