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What topical therapies are used in treatment of otitis? (5)
cerumenolytic agents, cleaning and drying agents, glucocorticoids, antiseptics, antimicrobials
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How should cerumenolytic agents be used?
apply 10 minutes prior to cleaning
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When are cerumenolytic agents contraindicated?
ruptured tympanic membrane or post-myringotomy
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What is the active ingredient in Cerumene, and what is special about this product?
Squalene; no hearing loss when injected into middle ear (NOT ototoxic)
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What cerumenolytic agent is commonly used in vetmed?
squalene
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How are cleaning and drying agents used? (3)
applied after cleaning with cerumenolytic agents, prophylactic treatment of swimmer's ear, maintenance ear program to keep infections from recurring
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What are the usual components of topical therapies?
antibiotics, antifungals, +/- glucocorticoids; vehicles for delivery: oil or ointment for dry lesions, solutions or lotions for moist lesions
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What is the purpose of using a topical glucocorticoid with otitis? (4)
antipruritic, anti-inflammatory, anti-proliferative, decrease sebaceous and apocrine secretions
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How do we select a topical antimicrobial agent?
- cytology: cocci Staph psedu, rods P. aeruginosa
- culture and sensitivity: main reason for culture are to ID organism and choose a systemic antibiotic (NOT for topical therapies)
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Categories of antibiotics for otitis. (4)
Aminoglycosides (neomycin, gentomycin, tobrmycin), Polymyxin B, Florfenicol, Fluoroquinolones (enrofolxacin, orbifloxacin)
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When are aminoglycosides indicated?
good activity against gram + and - (except P. aeruginosa)
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What should you be aware of when using aminoglycosides topically for otitis? (2)
inactivated in purulent debris (ie. clean the ear or else it won't work), ototoxic in humans
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What is your first line aminoglycoside for otitis externa (ie. the first drug you go for)? What is the exception?
Gentamycin and Neomycin; not with P. aeriguinosa...go for second-line drug
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What is your second line aminoglycoside? When is it used?
Tobramycin; great for Pseudomonas aeruginosa
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What is Polymyxin B used for?
P. aeruginosa is our primary indication, but it is effective against gram + and -
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What organism is Polymyxin B NOT effective against?
Proteus
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What is important to know when using Polymyxin B? (2)
inactivated in purluent debris (clean ears before administration), synergistic effects when combined with miconazole
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Polymyxin B is considered a(n) __________ drug.
second-line
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What is Florifenicol used for?
Staph pseud and E. coli
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What is Florfenicol NOT useful for?
Pseudomonas aeruginosa
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Florifenicol is considered a(n) _________ drug.
first-line
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How is Florfenicol used? (3)
gel put in ear, owner comes back in 7-10 days for re-dose, NO CLEANING ears
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When is the only time you use floroquinolones?
infections resistant to other antimicrobials and susceptible Pseduomonas aeruginosa infections
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Fluoroquinolones are considered __________ drugs.
second-line
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What is silver sulfadiazine?
second-line antibiotic used extra-label in ears
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What is tris-EDTA useful for?
cell surface of gram negative bacteria are damaged by exposure to EDTA, making it easier for antibiotics to effectively treat the infection
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When should you not use tris-EDTA?
gram positive infections.....waste of money
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What antifungals are common in otic topicals? (7)
Nystatin, thiabendazole, clotrimazole, miconazole, ketoconazole, posaconazole, terbinafine
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What is a perk of mometasone?
not systemically absorbed
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What compounds are used to ear mites (if topical treatment is preferred.....should probably use systemic treatment)? (4)
pyrethrins, thiabendazole, ivermectin, milbemycin
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What is "over-treatment"? (4)
too vigorous topical therapy, maceration of ear canal and white ceruminous debris, cytology shows only epithelial cells, decrease or discontinue topical medications
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When do we use systemic antibiotics in combination with our topical therapy?
otitis media [choose systemic antibiotic based on culture and sensitivity]
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What systemic antibiotics are commonly used for otitis media?
- Empirical (re-evaluate after C/S results come in): Cephalexin, Cefpodoxime, Clavamox [cocci on cytology]; Baytril, Zeniquin, Cipro [rods on cytology]
- After C/S results: change if resistant to empirical txt
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What parasiticides are used for ear mites? (2)
Selamectin, Imidacloprid
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When do we use systemic glucocorticoids? (3)
stenosis, edema, and hyperplasia of ear canal
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When agents are commonly used for maintenance ear therapy? (3)
ear cleaning and drying agent, tris-EDTA, +/- GCs
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How do you approach acute otitis externa?
empirical txt based on cytology, re-evaluation in 2 weeks
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How do you approach chronic recurrent or unresponsive otitis?
cytology +/- bacterial culture and sensitivity, find underlying disease (allergies, etc), evaluate for concurrent otitis media
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