Opthalmic Drugs Flashcards
T/F: topical preparations have low local concentration and high systemic absorption
FALSE, its the opposite
why should you wait 5 minutes between giving eye drops?
because the excess spills over or drains through nasolacrimal duct (absorbed by mucous membranes or swallowed) which impacts efficacy
what is the solution to a horse trying to kill you because you’re treating them with topical opthalmic medication 12x/day?
subpalpebral lavage systems
what animal is known to have more tear production and therefore more “washing” of the eye surface?
horses
miosis is due to contraction of what muscle?
iris sphincter muscle
T/F: SNS effects will contract the ciliary body
FALSE, PSNS
a 1500 lb kodiak bear is chasing you!! your SNS takes action and relaxes the ciliary bodies of your eyes resulting in what kind of vision?
far vision, so you can get the hell out of there
mydriasis is due to contraction of what muscle?
iris dilator muscle
T/F: the PSNS results in production of aqueous fluid
FALSE, SNS
T/F: miotics result in pupil constriction which opens the drainage angle
TRUE
what kind of aqueous outflow does the PSNS increase?
uveoscleral aqueous outflow
when would you not want to use miotics?
when a patient has anterior uveitis or an anterior lens luxation
what miotic is used primarily for diagnosis of parasympathetic lesions?
pilocarpine (direct acting parasympathomimetic)
remember our good old friend atropine? what is it’s MOA?
direct acting parasympatholytic (anticholinergic)
what does atropine cause when used topically?
mydriasis and cycloplegia
cycloplegia
paralysis of ciliary muscle leading to blurred vision
what is the effect of applying atropine topically in a patient with uveitis?
can break up synechiae by forcing the pupil open (little attachments where fibrosis and scarring cause the iris to be stuck on the lens)
T/F: atropine lasts longer than glycopyrulate
FALSE, opposite
what animal would you be concerned with when using atropine topically (leading to cycloplegia)?
horses!! they can’t handle blurred vision
what topical opthalmic drug can cause cats to froth at the mouth when given drops?
cats because of bitter taste
which has a faster onset and shorter duration, tropicamide or atropine?
tropicamide
what is the main indication for tropicamide?
dilating the pupil for opthalmic (funduscopic) exams
which has more effective pain control, tropicamide or atropine?
atropine
T/F: using tropicamide can alter a Schirmer’s tear test
TRUE, do Schirmer’s test FIRST
what can tropicamide help prevent post cataract surgery?
adhesions
what opthalmic drug is used commonly for diagnosis and localization of Horner’s syndrome?
phenylephrine
why is phenylephrine sometimes used for perioperative use in cataract surgery?
reduction of posterior synechiae formation
T/F: phenylephrine is a good choice when you want to cause adequate mydriasis in cats and horses
FALSE, unlikely, need to use in combination w/ another agent
what opthalmic drug would you use to prevent glaucoma in the contralateral eye?
timolol (opthalmic nonselective beta-antagonist)
what mechanism does brinzolamide use?
reversible inhibition of carbonic anhydrase which decreases aqueous humor production resulting in reduced IOP
what do you need to be cautious of when using sulfonamide derivatives?
hypersensitivities to sulfa
which stings more, dorzolamide or brinzolamide?
dorzolamide
what is the effect of inhibiting carbonic anhydrase?
decreases aqueous humor production which results in reduced IOP
what topical opthalmic is useful in treating glaucoma in dogs but is NOT effective in horses and cats?
topical prostaglandin analogs (i.e. latanoprost)
what is the mechanism of prostaglandin agonists?
they increase uveoscleral outflow by stimulating FP (prostaglandin) receptors in the eye
what topical opthalmic is often used in emergency management of glaucoma?
latanoprost
what are natural tears made up of?
mucin, water, lipid film
T/F: lacrimomimetic agents provide lubrication by perfectly replicating natural tears
FALSE, natural tears are complicated, not perfect replication
what topical opthalmic drug is use in the treatment of canine KCS (keratoconjunctivitis sicca)?
cyclosporine (lacrimogenic agent)
what are the two effects of cyclosporine?
increased tear production and local immunosuppression
T/F: dry eye is usually immune-mediated
TRUE, why you use immunosuppressors to treat
what is the purpose of using topical glucocorticoids?
to manage inflammatory and immune-mediated conditions (i.e. non-infectious keratitis, uveitis)
what type of drug is deamethasone?
topical glucocorticoid
T/F: prednisolone is a topical mineralcorticoid used to manage inflammatory and immune-mediated conditions
FALSE, = topical GLUCOcorticoid
why is the use of topical glucocorticoids contraindicated in patients with corneal ulcers?
because it impairs healing, also don’t use w/ infection or diabetes
when would you choose to use an NSAID vs. topical steroid?
when higher local concentration and lower systemic concentration is needed
why are topical NSAIDS contraindicated in corneal ulcerations, glaucoma, and coagulopathies?
they can be irritating and cause burning/stinging
what are two examples of topical NSAIDS?
flurbiprofen and diclofenac
what are good topical opthalmic drugs to use for managing inflammation associated w/ cataracts?
topical NSAIDS (flurbiprofen, diclofenac)
T/F: antimicrobial agents are typically used to treat opthalmic conditions including uveitis, conjunctival/corneal infectious diseases and inflammation
FALSE, only typically used to treat conjunctival and corneal infectious diseases
what might you be concerned about when using antimicrobial agents as topical therapies?
they can circumvent systemic toxicity issues (i.e. aminoglycosides and polymyxin)
T/F: antibiotics are typically used as adjunct/preventative therapy
TRUE
what two antibiotics can cause a rare anaphylactic rxn in some cats?
polymyxin and bacitracin
what are the potential adverse effects of antiviral agents?
bone marrow, hepatic, and renal toxicity
cuddles is having some eye troubles and you want to measure his IOP with a tonal pen, what would you typically use to decrease his corneal sensation so you don’t lose a finger?
proparacaine (topical anesthetic)
