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)
Systemic carbonic anhydrase inhibitors function, ADR’s (4), examples (3)
- PO agents that lower IOP by decreasing production of aqueous humor in patients who do not respond to first line agents and B blockers
- Malaise, anorexia, parasthesias, acidosis
- Acetazolamide (diamox), dichlorphenamide, methazolamide
Which is preferred in ocular treatment? Topical or systemic carbonic anhydrase inhibitors?
Topical
Topical carbonic anhydrase inhibitor examples (2) and ADR’s (2)
- Dorzolamide (trusopt) and brinzolamide (azopt)
- Ocular stinging, bitter taste, NO acidosis,
a2 agonist function in IOP and 1 example
- Lower aqueous humor production like B blockers and increase uveoscleral outflow used for short term therapy of open angle glaucoma and supplemental, as well as preoperative medications
- Brimonidine (alphagan)
Osmotic agents function, 4 examples, ADR’s (4)
- Used for rapid and significant reduction in IOP
- mannitol, urea, glycerin, isosorbide
- Systemic hyperosmolarity and electrolyte abnormality causing thirst, confusion, diuresis, rebound IOP
Netarsudil (rhopressa) mech of action, function and ADR’s (1)
- New agent that inhibits norepi transporter reducing resistance in trabechular network outflow pathway by modifying cytoskeleton, decreasing aqueous humor production and increasing outflow
- Used in refractive when 1st line agents are not successful in treating glaucoma
- Corneal verticella (corneal deposits forming a golden brown whorl pattern on inferior cornea that is reversible)
Cycloplegic
Drugs that cause paralysis of ciliary muscle
Cycloplegics and mydriatics function
Used to facilitate ophthalmic exams and surgeries by facilitating observation of eyes interior and preventing lens undergoing changes during assessment either by being anticholinergic or adrenergic agents (adrenergic just produce mydriasis)
2 mainstays of treatment for anterior uveitis
- Glucocorticoid to reduce inflammation
- anticholinergic
Risks of cycloplegics and mydriatics
Can induce closure of filtration angle in individuals who have narrow angle to begin with causing acute angle closure glaucoma
Age related macular degeneration mech of action and 2 types
- Painless progressive disease that blurs central vision limiting perception of fine detail where symptoms result from injury to macula, leading cause of blindness in older americans
- either dry (atrophic) which is more common and are characterized by presence of drusen (yellow deposits under retina where # and size of them relate directly to lack of vision quality) or wet (neovascular) which is more severe and progresses faster caused by new subretinal blood vessels often fragile and leaky and quickly causes permanent damages
Age related eye study (AREDS)
Study that demonstrated that high doses of antioxidant and zinc can reduce development of advanced ARMD
Management of wet (neovascular) ARMD (2)
- Laser therapy
- photodynamic therapy (high affinity drug for neovascular tissue and then infrared laser shined to activate drug to seal vessel, 5 days after must avoid light to avoid activation that could cause severe skin burn)
Angiogenisis inhibitors mech of action, administration, ADR’s (3)
- Inhibit new vessel growth in patients with neovascular ARMD by antagonizing vascular endothelial growth factor
- administered by direct injection into affected eye
- Endophthalmitis (inflammation inside eye caused by infection), blurred vision, cataracts
Ranibizumab, bevacizumab, pegaptinab, and aflibercept function
Approved for treatment of neovascular ARMD
Demulcents function
Artificial tears, isotonic solutions used as subs for natural tears to treat dry eye syndromes, provide relief of discomfort caused by irritants, lubrication of artificial eyes
Topical cyclosporine (restasis) function
Treatment of dry eyes thru unknown mechanism that can take up to 3 months for full effect with minimal to no systmeic or topical toxicity reported
Lifitegrast (Xiidra) function
LFA-1 antagonist that prevents inflammatory factors from T cells being active on the ocular surface treating dry eyes
Topical antibiotics are often used…
….post operatively to prevent infection after ocular surgeries such as cataract surgery
Patients should not wear contact lenses while they have…
…eye infection or while treating infection with topical agent
Allergic conjunctivitis treatment and 2 examples
Antihistamines most often 2nd gen non sedating agents such as zyrtec (ceterizine) or fexofenadine (allegra)
Topical glucocorticoids function and 2 examples
- Highly effective at treating allergic conjunctivitis but have serious ADR’s such as cataracts, infections, or elevation of IOP so reserved for short term therapy, prolong infection due to immunosuppressant function so contraindicated in any infection
- loteprednol, fluoromethalone
Topical NSAIDS function and example
- Antiinflammatory activities inhibit prostaglandin production, play role in miiotic response by constricting iris sphincter independent of cholinergic mechanisms
- diclofenac (voltaren)
Components to consider in ophthalmic products (5) and why does it matter?
- sterility
- buffer btwn 6-8 acceptable for eye
- tonicity
- vehicle
- viscosity increasing agents
-Patients might have hypersensitivity rxn to any of the components used in ophthalmic products which may necessitate discontinuing agent and switching to another product that does not contain irritating agent
