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24 Cards in this Set
- Front
- Back
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What choices are there for administration route of ocular drugs? |
-Topical = reaches ocular surface to posterior lens capsule (great because you can get high concentration to AVASCULAR cornea; anterior uveitis, corneal disease) -Systemic = for blepharitis, orbit, posterior segment, and in cases of perforated globe) |
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What are the barriers to both topical and systemic drugs? |
Topical = tear film (dilutes and removes drug); conea (epithelial cells have tight junctions, but if epithelium is removed, drugs will get there!); high water content of corneal stroma (hydrophilic - drugs must be lipophilic and hydrophilic) Systemic = Blood eye barrier (goal is to keep everything out so that you can see clearly) |
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Where do topical drugs go? |
Simple, extraocular/intraocular structures -->tears will wash out the material! Bigger drops = more will wash out! Down nasolacrimal duct --> then can go into GI (but small volumes won't have systemic effect) Drooling is common in cats (atropine!) Conjunctival absorption --> blood vessels --> system Transcorneal absorption --> aqueous humor (goal!!) Drops are typically gone within 5 minutes! Need to wait 5 minutes between treatments! |
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What are the different types of Topical Drugs? |
Solutions = most common; water soluble, drug completely dissolves in solvent; shortest duration Suspensions = most steroids; particles of active ingredient and saturated aqueous vessle; can irritate; moderate duration Ointments = drug mixed into melted vehicle then cooled; greasy, blurs vision, humans don't like using it! Longest duration |
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What dosing frequency is used for topical drugs? |
-Consider several factors: -mild to severe disease -vehicle = ointment will be less frequent than solutions -prophylaxis or treatment? -spacing of drugs (5 mins between solutions, 30 mins between ointments) -volume - 1 drop or 1/4 inch strip -species = hard to tilt a horses head! |
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What are compounded drugs? |
Drugs that are made by the pharmacist (especially when drugs are no longer available or if they were never commercial available) = more common in optho!! |
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Topical Antibiotics - Feline Conjunctivitis |
-Feline conjunctivitis is due to herpes (can't treat w/abx!), chlamydia, or mycoplasma (most often) -Can use erythromycin, tetracyclines (variable activity), or ciprofloxacin -Dosed BID to TID for several weeks |
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Topical Antibiotics - Non-Infected Corneal Erosions |
-Non-infected superficial epithelial erosion = prophylaxis! Broad spectrum! -Neomycin/"Triple" (gram - and +) BID/TID -Neopolybac = ointment -Neopolygram = solution |
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Topical Antibiotics - Infected Corneal Erosions/Ulcers |
Broad Spectrum Abx -Neomycin BID x 24 hours; then SID -Can do combination therapies |
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Antiviral treament |
Herpes virus - nearly all cats have been exposed Large % of cats will shed -Causes conjunctivitis, corneal ulceration, uveitis 1. Nucleoside analogs (substitutes nucleoside in DNA and interferes with polymerase) - static 2. Trifluridine (expensive!); Idoxiuridine; Gancyclovir (expensive!); Cidofovir 3. Oral Antivirals = may affect bone marrow and kidneys! Not safe! Famciclovir = safe version! undetermined dose. |
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Antifungal treatments |
-Basically used in Equine Corneal Fungal Infection -Ointment is easier, liquid is used for lavage! -Polyene = bind to sterols in membranes -Azoles = increase cell permeability (best activity in equine isolates!) -Fungicidal |
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What are the polyene antifungals? how to they work? |
1. Natamycin (5%) -the only one! -thick solution - need to thin it out -poor penetration through intact epithelium -horses can get stromal abscesses that cannot be reached by natamycin |
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What are the azole antifungals? |
Compounded meds! 1. Itraconazole ointment = good absorption thru intact epithelium (cannot use lavage tube) 2. Miconazole (1%) - in DMSO, can be irritating 3. Voriconazole 4. Monostat! Yeast infection drug is used especially in cases where the owner cannot afford the other drugs |
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Treatment of Keratoconjunctivitis Sicca |
-Dry eye (tear produced by lacrimal gland is insufficient) -Causes keratitis, conjunctivitis, corneal pigmentation, mucopurulent discharge -Immune mediated is most common reason -Treatment = replace tears; reduce T-lymphocyte destruction (cyclosporine); direct lacrimogenic effect increases tear production = Optimune (cyclosporine A); Tacrolimus (works in dogs who are not responsive to optimune!) |
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Treatment of Glaucoma |
Glaucoma = increased intraocular pressure Normally = aqueous production equals outflow, but now the outflow is impeded Drugs target: aqueous production, aqueous outflow; underlying condition causing glaucoma! 1. Hyperosmotid diruetics = mannitol dehydrates vitreous; only for primary glaucoma (outflow issue intrinsic to outflow) -- short term only (NOT for diabetics or heart disease) 2. Prostaglandin derivatives Latanoprost/Xalatan = increased aqueous outflow, may decrease production; dogs only -- causes miosis; good in emergencies! Only primary glaucoma 3. Carbonic Anhydrase Inhibitors = decrease aqueous production; topical or oral; diuresis, GI, increased RR, decreased K+ (topical is best); primary and secondary glaucoma! 4. Cholinergics Pilocarpine; Demecarium Bromide = (increase aqueous outflow); miosis; effect = uveitis, salivation, vomit, diarrhea; primary only 5. Topical Adrenergic blockers (Timolol, Betaxolol) - (decrease aqueous production and may increase outflow); prophylaxis 6. |
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Drugs that cause miosis? |
Only indicated in primary glaucoma Side effect = uveitis (typically used in conjunction with topical steroid!) |
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Topical corticosteroids - indications |
Used to treat anterior uveitis Corneal penetration is essential Surface inflammation is usually immune mediated Many different options - only a few to use! Contraindicated with corneal ulcers |
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Topical corticosteroids; corneal penetration |
Acetates > Alcohols > Phosphates Use Prednisolone acetate or Dexamethasone alcohol to get into the eye Use Dexamthasone NaP for topical Don't use if there is an ulcer! |
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Which drugs to use as topical corticosteroids? |
Prednisolone Acetate 1% or Dexamethasone 0.1% (often with neomycin) |
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What are the side effects of steroids? |
Delays corneal wound healing! Thins epithelium! Promotes protease activity --> corneal melting Reactivation of herpes is possible Lipid deposits in cornea Iatrogenic Cushing's? |
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What are the indications of topical NSAIDS |
Good corneal penetration - some intraocular penetration Used for uveitis, surface analgesia May potentiate bacterial infection and corneal melting |
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What are the topical NSAIDs? |
1. Flurbiprofen (can cause hyphema) 2. |
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What drugs are used to dilate the eye? |
1. Atropine 1% - parasympatholytic (long acting!) - paralyzes the ciliary body; can be pain relieving by reducing ciliary body spasms in uveitis; stabilizes blood aqeuous barrier Ointment to prevent drooling; can lower tear produciton; decreases GI motility in horses |
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what drugs are used to facilitate the eye exam? |
Proparacaine HCL 0.5% -topical anesthetic -facilitates taking samples; measuring intraocular pressure (culture/cytology/biopsy) -Epitheliotoxic! Drying! Delays wound healing Tropicamide 1% -dilator -short acting for retinal exams |
