COT Ophthalmic Pharmacology 3 — Questions and Answers
Question 1: Timolol maleate ophthalmic solution is contraindicated in patients with which systemic condition?
- Type 2 diabetes mellitus
- Reactive airway disease or asthma (Correct answer)
- Hypertension
- Hypercholesterolemia
Correct answer: Reactive airway disease or asthma
Timolol is a non-selective beta-blocker that can cause bronchospasm by blocking beta-2 receptors in the lungs, making it contraindicated in patients with asthma or COPD.
Question 2: Which mydriatic agent provides both pupil dilation AND cycloplegia (paralysis of accommodation)?
- Phenylephrine
- Tropicamide (Correct answer)
- Naphazoline
- Apraclonidine
Correct answer: Tropicamide
Tropicamide is an anticholinergic agent that blocks muscarinic receptors causing both mydriasis and cycloplegia, making it useful for refraction and fundus examination.
Question 3: A patient reports that their eye drops turn the iris from blue to brown over time. Which drug class is responsible for this pigmentation change?
- Beta-blockers
- Alpha-2 agonists
- Prostaglandin analogs (Correct answer)
- Carbonic anhydrase inhibitors
Correct answer: Prostaglandin analogs
Prostaglandin analogs (e.g., latanoprost, bimatoprost) can stimulate melanogenesis in iris melanocytes, causing irreversible increased iris pigmentation over months to years.
Question 4: Which ophthalmic preservative found in many multi-dose eye drop bottles is known to be toxic to the corneal epithelium with long-term use?
- Sodium chloride
- Benzalkonium chloride (BAK) (Correct answer)
- Sodium hyaluronate
- Hydroxypropyl methylcellulose
Correct answer: Benzalkonium chloride (BAK)
Benzalkonium chloride (BAK) is a detergent-type preservative that disrupts the lipid layer of the tear film and is directly toxic to corneal epithelial cells with chronic exposure.
Question 5: Cyclopentolate is preferred over atropine for routine pediatric cycloplegic refraction primarily because:
- It produces stronger cycloplegia than atropine
- Its effects last hours rather than days, reducing systemic toxicity risk (Correct answer)
- It does not cause mydriasis
- It is the only agent effective in heavily pigmented irides
Correct answer: Its effects last hours rather than days, reducing systemic toxicity risk
Cyclopentolate's effects resolve within 24 hours compared to atropine's 1–2 weeks, reducing the risk of prolonged systemic anticholinergic toxicity in children.
Question 6: Which of the following medications is an alpha-1 adrenergic antagonist used to dilate the pupil without causing cycloplegia?
- Atropine
- Cyclopentolate
- Phenylephrine (Correct answer)
- Tropicamide
Correct answer: Phenylephrine
Phenylephrine stimulates alpha-1 receptors in the dilator pupillae muscle causing mydriasis without affecting the ciliary muscle, so accommodation is preserved.
Question 7: Acetazolamide (Diamox), an oral carbonic anhydrase inhibitor, is commonly associated with which adverse systemic effect?
- Hypokalemia and metabolic acidosis (Correct answer)
- Hyperkalemia and metabolic alkalosis
- Hyponatremia and dilutional anemia
- Hypercalcemia and nephrolithiasis
Correct answer: Hypokalemia and metabolic acidosis
Acetazolamide causes a bicarbonate diuresis leading to metabolic acidosis and potassium wasting (hypokalemia), which may require potassium supplementation.
COT Ophthalmic Pharmacology 3
Timolol maleate ophthalmic solution is contraindicated in patients with which systemic condition?