Ophthalmological Pharmacotherapy Lecture PDF Flashcards
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Aqueous humor production and travel
- Occurs in the ciliary body and secreted into the posterior chamber of the eye (behind the iris)
- then travels around the iris into the anterior chamber where it is drained (drains via trabechular canal of shlemm
Angle closure glaucoma can cause the iris to be….
….pushed up against the cornea as pressure builds in the eye
Unconventional outflow pathway
Aqueous humor drainage via uveoscleral outflow to remove from anterior and posterior chamber in a way other than the trabecular meshwork
90% of glaucoma cases are what type?
Primary open angle
Risk factors of primary open angle glaucoma (4)
- African American heritage
- advancing age
- diabetes
- hypertension
Trabechulectomy
Most common procedure to reduce intraocular pressure that reates shunts to allow aqueous humor to exit anterior chamber, scarring may cause shunt to close
Angle closure glaucoma
Displacement of iris covers trabecular meshwork preventing aqueous humor from the anterior chamber exiting, development is suddenly painful and causes irreversible vision loss within 1 to 2 days
1st line treatment for glaucoma and 2nd line treatment
- Prostaglandin analogs
- B blockers
B blockers for glaucoma #1 used example, mech of action, function, ADR’s (4)
- Timolol
- Decrease production of aqueous humor thru unknown mechanism
- lower IOP 20-25% once or twice daily dosing, much less effective at night, equal efficient as pilocarpine to treat acute angle closure glaucoma
- Local stinging, conjunctivitis, bradycardia, bronchospasm
Prostaglandin analogs function
Topical usually lower IOP by 25-30% and are mainstay of glaucoma treatment
Latanoprost (Xalatan) drug class, mech of action, and ADR’s (3)
- Prostaglandin analog
- Enhances aqueous humor outflow via a dropper
- Heightened brown pigmentation of iris most noticeable in patients with green brown iris (irreversible), stinging, conjunctiva
Bimatoprost (Lumigan) function
Similar to latanoprost in function and marketed to increase eyelash length, darkness, and thickness
Pilocarpine drug class, mech of action, function, ADR’s (5)
- direct acting muscarinic agonist (parosympathomimetic agent)
- stimulates cholinergic receptors in eyes producing miosis and contraction of ciliary muscle to focus lens on near vision
- Used to treat open angle glaucoma by reducing tension generated by ciliary muscle and close angle glaucoma by allowing for contraction of iris sphincter to pull it away from the pores of the trabecular mesh work
- Contraction of lens causing difficulty seeing distance, bradycardia, urinary urgency, diarrhea, hypersalivation
How to reverse pilocarpine effects?
Atropine
Long acting cholinesterase inhibitors function and one drug example
- Inhibit breakdown of Ach allowing accumulation at muscarinic receptors producing same ocular effects as parasympathomimetic drugs such as pilocarpine
- echothiophate iodide (phosopholine iodide)