An elderly woman using topical eye drops for chronic open-angle glaucoma develops acute wheeze and breathlessness. She has known bronchial asthma. Which antiglaucoma medication is most likely responsible?
- A Timolol maleate ✓
- B Latanoprost
- C Brimonidine
- D Dorzolamide
Correct answer: A. Timolol maleate
Explanation
Timolol is a non-selective beta-blocker. Even as an ophthalmic preparation, significant systemic absorption occurs through nasal mucosa and conjunctiva, and blockade of airway beta-2 receptors can precipitate severe bronchospasm in asthmatics. Latanoprost, brimonidine and dorzolamide lower intraocular pressure by prostaglandin FP agonism, alpha-2 agonism and carbonic anhydrase inhibition respectively, and none of them antagonises bronchodilator beta-2 receptors.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.