Pharmacology Flashcards
What is the purpose of adding preservatives to ophthalmic preparations?
to maintain sterility of the medications
What are the types of preservatives that are added to ophthalmic preparations?
Detergent preservatives
Oxidizing preservatives
What is the MOA of detergent preservatives added to ophthalmic preparations?
Cause bacterial cell death by interrupting the lipid component of the bacterial cell membranes
What is the MOA of oxidizing preservatives added to ophthalmic preparations?
Penetrate the membrane and alters DNA, protein, and lipid components of bacterial cells
Better tolerated than detergent preservatives
What are some ways to avoid systemic side effects from topical ophthalmic drugs?
Prevent overdosing (>1 drop)
Prescribe lowest possible concentration
Educate patient to use only 1 drop
Ointments - educate patients to only use the size of a “match head”
Educate patient on how to occlude the lacrimal duct
What adverse ocular effects can be seen from systemic drugs?
Elevated intraocular pressure Cataracts Optic neuropathy - visual acuity Miosis Retinal problems (infarction, deposits, vascular occlusion, retinopathy, degeneration) Mydriasis Cycloplegia Nystagmus Conjunctival deposits Corneal opacity Pigmentation of lens Angle closure glaucoma Papilledema
What are adverse ocular effects that can be seen from ophthalmic drugs?
Allergic reactions Corneal opacities and infections Decreased wound healing Myopia Retinal detachment Angle closure glaucoma Blurred vision Cataracts
What is the MOA of prostaglandin analogues in the treatment of glaucoma?
increases outflow by increasing MMP expression and alters the matric in the ciliary muscle and trabecular meshwork
What prostaglandin drugs are used in the treatment of glaucoma? How much pressure reduction is expected from these drugs?
Latanoprost and brimatoprost
25% to 30% reduction in IOP is expected
What are the adverse effects of prostaglandin analogues?
Conjunctival hyperemia Irreversible darkening of the iris Increased length thickness and number of lashes Increase eyelid skin pigmentation Local irritation, itching, dryness, blurred vision Uveitis (rare) Macular edema (rare) Few systemic side effects
What is the MOA of beta blockers in the treatment of glaucoma?
Reduces inflow by regulating aqueous humor formation in the ciliary processes
What beta blockers are used in the treatment of glaucoma? How much pressure reduction is expected from these drugs?
Timolol
Levobunolol
Betaxolol
20% to 25% reduction in IOP is expected
What are the side effects of beta blockers when treating glaucoma?
Bradycardia Hypotension Bronchospasm Fatigue Dizziness Masking of hypoglycemia Exacerbation of CHF
How can systemic side effect be avoided in patients who take ophthalmic beta blockers?
Occluding the lacrimal tear duct for 2 minutes
What is the MOA of carbonic anhydrase inhibitors in the treatment of glaucoma?
Reduces aqueous humor formation by inhibiting HCO3 production in the ciliary epithelium
What carbonic anhydrase inhibitors are used systemically to treat glaucoma? What is the pressure reduction that is expected from this drug?
Acetazolamide
30% - 50% reduction in IOP
What are the side effects of using systemic (oral) carbonic anhydrase inhibitors?
Weak diuretic Paresthesia Metabolic acidosis Nausea/Vomiting Hypokalemia Hyponatremia Renal stones Bone marrow suppression (anemia, neutropenia, etc)
What are the carbonic anhydrase inhibitors that are used topically to treat glaucoma? What is the pressure reduction that is expected?
Brinzolamide, Dorzolamide
17% - 20% reduction in IOP
What are the side effects that can be seen with using topical carbonic anhydrase inhibitors?
Bitter taste Stinging Redness Burning Conjunctivitis Dry eyes Blurred vision
What is the MOA of alpha 2 adrenergic agonists in the treatment of glaucoma?
Reduces aqueous humor formation by decreasing the inflow via the inactivation of adenylyl cyclase in the ciliary process and affecting NE release
What are the alpha 2 adrenergic agonist that are used in the treatment of glaucoma? What is the pressure reduction that is expected?
Apraclonidine (not used very often due to tachyphylaxis and local allergic reactions)
Brimonidine (added neuroprotective effect)
15% - 25% reduction in IOP
What are the side effects that are expected from alpha 2 adrenergic agonists?
Local
- Blepharoconjunctivitis
- Foreign body sensation
- Mydriasis
- eyelid retraction
Systemic
- headache
- dry mouth
- fatigue
What types of drugs are used in acute situations to induce a rapid IOP change or in surgical procedures?
Osmotic agents
Oral glycerol
Isosorbide
IV mannitol
What is the MOA of osmotic agents in the treatment of glaucoma?
Increases the osmotic gradient between the eye and the circulating blood. Fluid will leave the eye and the IOP will decrease
