PH9.7 | PH9.7 | Ocular Pharmacotherapy and Topical Delivery — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

Anti-glaucoma drugs target either AH production or outflow: Prostaglandin analogues (latanoprost, bimatoprost — most potent, 25–35% IOP ↓, once daily evening, increases uveoscleral outflow; ADR: iris pigmentation, eyelash hypertrichosis); Beta-blockers (timolol non-selective, betaxolol β1-selective — reduce AH production; CONTRAINDICATED in asthma/COPD — systemic absorption via nasolacrimal duct); Alpha-2 agonists (brimonidine — dual: reduce AH + increase uveoscleral outflow; CONTRAINDICATED in infants <2 years — CNS depression); CAIs (dorzolamide/brinzolamide topical; acetazolamide oral — reduce AH production; acetazolamide ADR: metabolic acidosis, renal calculi, sulfa cross-reaction); Miotics (pilocarpine — muscarinic agonist, increases trabecular outflow; ADR: spasm of accommodation, brow ache); Hyperosmotic agents (mannitol IV — acute angle-closure emergency, reduces vitreous volume). Other ocular drugs: acyclovir ointment for HSV keratitis (NO steroids alone — causes corneal melting); olopatadine/ketotifen for allergic conjunctivitis; tropicamide for routine fundoscopy; atropine for amblyopia/uveitis; anti-VEGF (ranibizumab, bevacizumab) for wet AMD. Topical delivery: corneal absorption ~10%; 90% via nasolacrimal duct to systemic circulation bypassing first-pass; punctal occlusion reduces systemic absorption ~40–50%.

REFLECT

Think about the chain of events that led to the patient in the hook case (the man with COPD whose asthma worsened on timolol eye drops). At what point in the prescribing process could this adverse effect have been prevented? What information should the ophthalmologist gather before starting a beta-blocker eye drop? What should the dispensing pharmacist check? What should the patient be told? This case illustrates how eye drops are 'real drugs' with systemic effects — and how a complete drug history must always include eye drops, ear drops, and other topical preparations that patients often do not consider to be 'medications.' How will you ensure you capture the full topical drug history in every patient interaction?