Ocular Pharmacology Flashcards
What are the different topical ocular antibiotics
1) Neomycin, Polymyxin B, Bacitracin
2) Neomycin, Polymyxin B, Gramicidin
3) Ofloxacin or Ciprofloxacin
4) Moxifloxacin 0.5%
5) Tobramycin
6) Gentamicin
7) Erythromycin
8) Terramycin (Oxytetracycline, Polymyxin B)
9) Chloramphenicol
10) Cefazolin
Neomycin, Polymyxin B, Bacitracin has what spectrum
broad spectrum (gram positive and gram negative)
What is a downside of Neomycin, Polymyxin B, Bacitracin
1) Does not penetrate an intact corneal epithelium
-used for uncomplicated ulcers
-not recommended for active infections
2) Caution in cats (polymyxin anaphylaxis)
T/F: Neomycin, Polymyxin B, Bacitracin is for active infections
False - used for uncomplicated ulcers
DOES NOT penetrate an intact corneal epithelium
Neomycin, Polymyxin B, Bacitracin cannot penetrate what structure
an intact corneal epithelium
What species should you use Neomycin, Polymyxin B, Bacitracin cautiously in
cats - polymyxin anaphylaxis
you can still use it, just be careful
administer dose in clinic and wait 30 minutes to see if it is their first dose
How does Neomycin, Polymyxin B, gramicidin differ from Neomycin, Polymyxin B, Bacitracin
Gramicidin is a solution (instead of an ointment)
Neomycin, Polymyxin B, Bacitracin is for uncomplicated ulcers, what is recommended for actively infected corneal ulcerations
Ofloxacin or Ciprofloxacin
they are fluoroquinolones with gram postive and gram negative (good penetration through intact epithelium)
Ofloxacin, Ciprofloxacin, and Moxifloxacin are optic solutions for what
actively infected corneal ulcerations (not for simple ulcers)
good penetration through intact epithelium
T/F: tobramycin penetrates an intact epithelium
True - it does
it is good for simple ulcers in higher risk patients (brachycephalics)
not epithelial toxic
Aminoglycosides that are used as topic ocular antibiotic
Tobramycin and Gentamicin
good activity against gram negative
What ocular antbiotic is a middle road medication between the fluoroquinolines (Ofloxacin or Ciprofloxacin) and NeoPolyBac
Tobramycin
an aminoglycoside (gram negative)
does penetrate an intact epithelium (good for simple ulcers in high risk patients (brachycephalics)
not epithelial toxic
Tobramycin
Is Tobramycin or Gentamicin epithelial toxic
Gentamicin is epithelial toxic over long periods of use
why should you only use gentamicin if culture indicates
because it is epithelial toxic over long periods of use
Erythromycin is effective against what bugs
Macrolide - mainly effective against gram positive
effective against Chlamydophilia and Mycoplasma (causative agents for conjunctivitis in cats)
What topical antibiotic would you use for conjunctivitis in cats
Erythromycin
Macrolide - mainly effective against gram positive
effective against Chlamydophilia and Mycoplasma (causative agents for conjunctivitis in cats)
What is Erythromycin commonly used for
Cats with
1) Conjunctivitis (active against Chlmaydophilia and Mycoplasma)
2) Uncomplicated corneal ulcerations
What two drugs are in Terramycin ointment
1) Oxytetracycline
2) Polymyxin B
gram negative and positive coverage
beware cats - polymixin anaphylaxis
What are the used of Terramycin
1) Effective against chlamydophilia and mycoplasma
2) Shown to reduce healing time in dogs with SCCED (indolent ulcers)
T/F: Chloramphenicol penetrates an intact corneal epithelium
True
What is chloramphenicol solution or ointment effective against?
gram postivie and negative
penetrates an intact corneal epithelium
What is a major concern with giving Chloramphenicol ophthalmic solution / ointment
Can cause APLASTIC ANEMIA - dose independent and fatal
*only use if culture indicates and you will loose the eye without treatment
Have owners sign a waiver, must wear gloves
Only use Chloramphenicol if ___________ due to _________
only use it if culture indicates and you will loose the eye without treatment
have owners sign a waiver, must wear gloves
causes aplastic anemia (owner risk) dose independent and fatal
a first generation cephalosporin (gram + coverage)
use with gram negative coverage antibiotic
does not penetrate intact epithelium
injection used as ophthalmic solution
compounded, check local laws
Cefazolin
T/F: Cefazolin penetrates an intact epithelium
False
T/F: Tobramycin penetrates an intact epithelium
True
Fluoroqinolines (Ofloxacin, Ciprofloxacin, and Moxifloxacin) penetrates the intact epithelium
True
Morris labrador squinting OS 2 days ago
-Belpharospasm
-Epiphora
-Faint Fluorescein stain uptake OS
2mm superficial corneal ulcer just ventral to the central cornea
What is the diagnosis and treatment
Simple Corneal Ulceration
heals within 5-7 days
not infected
superficial
treat with NeoPolyBac
You have a dog with a complicated infected and melting corneal ulceration. What medication do you give
Ofloxacin - big gun antibiotic with good penetration
you could also add Cefazolin but dont use alone
used to stabilize the cornea with keratomalacia
(bacteria and WBCs produce collagenases which melt corneal collagen)
Anti-Collagenase medications
1) Serum
2) Acetylcysteine
3) EDTA
4) Doxycycline
What are the different Anti-Collagenase medications
1) Serum
2) Acetylcysteine
3) EDTA
4) Doxycycline
How is serum used as anti-collagenase medications
Collected from patient (can cross species)
must be refrigerated (good for 1 week) or frozen for longer storage
What is a downside of using serum for anti-collagenase medications
1) Irritating and pro-inflammatory
2) takes a lot of time
What is the preferred anti-collagenase medication
Acetylcysteine
How is acetylcysteine used as anti-collagenase medication
compounded into 4-5% solution from the 20% oral / injectable form
can be added directly to Ofloxacin (check local compounding laws)
What antibiotic can be used as anti-collagenase
Doxycycline - concentrates in. the tear film and gets some anti-collagenase activity (not preferred)
3yo FS DSH with
-Belpharospasm and epiphora
-Severe Blepharoedema/ Blepharitis
-Severe chemosis (swollen conjunctiva) and moderate conjunctival hyperemia
What antibiotic would you start morris on
Erythromycin - bilateral (tells it might be chlamydia or mycoplasma) need a macrolide to target these bugs
Cat with blepharospasm, epiphora, multifocal superficial dendritic corneal ulcerations
What is cause and how do you treat
FHV-1 (dendritic corneal ulcerations - unilateral)
cant use antibiotic for virus
do anti-viral medications
T/F: FHV-1 causes dendritic ulcers bilaterally
False - it is a unilateral disease
causes chemosis in cats often bilateral
Chlamydophilia
causes hyperemia and typically unilateral in cats
FHV-1
What are the different anti-viral medications you can do
1) Cidofovir (compounded solution BID)
2) Idoxuridine (compounded solution or ointment 5x)
3) Famciclovir (oral BID to TID)
What is a downside of using Idoxuridine
it needs to be applied >5 times a day
(Cidofovir is only twice a day)
Is cidofovir or idoxuridine more practical for owners
Cidofovir (2 times and day instead of 5)
an oral anti-viral medication
Famciclovir - oral works because it is latent at the nerve
stops it at the place the virus is living
Not an anti-viral (supplement)
stops viral replication due to a competitive imbalance between L-lysine and arginine
reduces the severity and frequency of FHV-1 flareups
L-lysine
T/F: L-lysine helps acute flareups of FHV-1
False - it reduces severity and frequency of flareups
some cats, might make flareups worse
What do you do if L-lysine makes FHV-1 flareups worse
Stop it
What is dose of L-lysine
500mg PO BID - needs to be given frequently because you need more L-lysine than arginine to reduce the severity and frequency of flareups
What are different topical anti-inflammatories
1) Prednisolone acetate
2) Dexamethasone sodium phosphate
3) Flurbiprofen (NSAID)
4) Diclofenac (NSAID)
5) Ketorolac (NSAID)
T/F: Prednisolone acetate penetrates the cornea
True - can be used for intraocular inflammation
Do not use prednisolone acetate if
there is a corneal ulcer
Why might you use prednisolone acetate
1) Intraocular inflammation
2) Immune mediated keratitis
T/F: Dexamethasone sodium phosphate penetrates the cornea well
False - use prednisolone acetate instead
Dex is best used for conjuctivitis
Do not use dexamethasone sodium phosphate if there is
a corneal ulcer
Equine patients receiving dexamethasone sodium phosphate, you need to watch for
fungal keratitis and stromal abscesses
What are the different NSAID ophthalmic solutions
1) Flurbiprofen (NSAID)
2) Diclofenac (NSAID)
3) Ketorolac (NSAID)
T/F: NSAIDs are not as strong as topical steroids
False
Why do you typically not want to use topic anti-inflammatories on cats *
because cats commonly get infectious disease, inflammation might go away but as soon as you take it away they are toast
dogs also can get immune mediated diseases where youll want to use NSAIDs and steroids
T/F: Dexamethasone is more potent, so it should be used for aggressive topical anti-inflammatory targeting over prednisolone acetate
False - even though Dex is 7-10x more potent than Pred. Pred is still used because it comes in the 1% solution while Dex comes in the 0.1% solution
plus pred can penetrate the corneal wall (better for uveitis)
Does Prednisolone or Dex penetrate the corneal wall
Prednisolone acetate
T/F: NSAIDS like Flurbiprofen, Diclofenac, and Ketorolac penetrate the cornea
True- NSAIDs are useful for long term uveitis prevention (eg. lens induced uveitis)
You should avoid or reduce the use of NSAIDS like Flurbiprofen, Diclofenac, and Ketorolac when
a corneal ulcer is present
can delay healing, but not as bad as steroids
can become epithelial toxic when used more than QID
if uveitis if bad enough that QID is required then you should use a steroid
When giving NSAIDS like Flurbiprofen, Diclofenac, and Ketorolac, what can occur if given QID
epithelial toxic when used more than QID
go on steroid if uveitis is bad enough where QID is needed
What are different topic antibiotic / anti-inflammatory combinations
1) Neomycin-Polymyxin-Dexamethasone
2) Neomycin-Polymyxin B- Bacitracin - Hydrocortisone
3) Tobramycin-Dexamethasone
What is classic clinical use for NSAIDS like Flurbiprofen, Diclofenac, and Ketorolac
mature cataract - autoimmune attack against lens protein (lens uveitis)
Neomycin-Polymyxin-Dexamethasone is most effective against
allergic conjunctivitis in dogs (inflammatory)
Dont use Neomycin-Polymyxin-Dexamethasone if there is a
corneal ulcer
What is the risk of giving Neomycin-Polymyxin-Dexamethasone to cats
Cats can get infectious conjunctivits (eg. FHV-1) from the immunosuppression Dex
What is the risk of giving Neomycin-Polymyxin-Dexamethasone to horses
Horses can get stromal abscesses and fungal keratitis
Why is Neomycin-Polymyxin B- Bacitracin - Hydrocortisone useless
because it does not penetrate the cornea and is not a strong steroid (not very useful)
T/F: Neomycin-Polymyxin B- Bacitracin - Hydrocortisone can penetrate the cornea
False - this is useless
cant penetrate the cornea and not a strong steroid
What is a downside of using Tobramycin-Dexamethasone
historically expensive but more affordable option will happen soon
like $100 more for same result
How do you avoid mix up of ophthalmic medications with and without steroids
they all look the same so keep on different shelves
10 yo poodle. both eyes have cloudy and vision is deteriorating
intact PLR but negative menace
Diffuse lens opacity
Diagnosis? Medication?
Cataracts - loss of menace
Start them on topical Diclofenac to prevent lens induced uveitis flareups
not severe enough where you dont need to go to pred or Dex
2yo MC german shorthaired pointer
just returned from camping trip to North Dakota
OU blepharospasm and epiphora
episcleral injection
mild diffuse corneal edema
Miotic pupil
Negative Fluorescein stain
What is your diagnosis? What is your treatment?
Active anterior uveitis
need to get aggressive with treatment
Prednisolone acetate - active uveitis needs a stronger medication
need to run diagnostics and treat with systemic medications
What breeds commonly get primary glaucoma
1) Cockerspaniel
2) Basset Hound
Do patients with glaucoma have miotic or mydriasis pupils
Mydriatic (dilated) pupil
What are the 4 physical exam findings of glaucoma
1) Mydriatic (dilated) pupil
2) Episcleral injection
3) Diffuse corneal edema
4) Elevated IOP
What are the different glaucoma medications?
1) Timolol (b blocker)
2) Dorzolamide (topical carbonic anhydrase inhibitor)
3) Methazolamide (oral carbonic anhydrase inhibitor)
4) Latanoprost (Prostaglandin analog)
How does timolol help patients with glaucoma
it is a Beta-blocker solution
decreases the aqeuous humor production through the blockage of beta-receptors in ciliary body
only a mild decrease in IOP
What are the side effects of timolol solution for glaucoma
mild bradycardia
What top is the timolol ophthalmic solution
Yellow top
What type of animals is timolol not permitted
racehorses due to anti-doping rules
What is the mechanism of action of carbonic anhydrase inhibitors like Dorzolamide and Methazolamide
inhibits carbonic anhydrate enzyme which is found in the ciliary body epithelium that helps produce aqueous hyumor
topical carbonic anhydrase inhibitor for glaucoma treatment
Dorzolamide
What color top is the topical carbonic anhydrase inhibitor Dorzolamide
orange (trusopt)
oral carbonic anhydrase inhibitor for management of glaucoma
Methazolamide - higher risk of systemic side-effects (metabolic acidosis)
Methazolamide is an oral carbonic anhydrase inhibitor, that has more systemic side effects than the topical Dorzolamide. What is the side effect
Metabolic acidosis
Cosopt is what two medications
Dorzolamide and Timolol (dark blue top)
What color top is Dorzolamide and Timolol (Cosopt)
Dark blue top
What is the mechanism of action of Prostaglandin Analogs like Latanoprost (Xalatan)
increases aqueous outflow and may also decrease aqeuous production to some degree
increases aqueous outflow and may also decrease aqeuous production to some degree
Prostaglandin Analogs like Latanoprost (Xalatan)
Prostaglandin Analogs like Latanoprost (Xalatan) cause what side effect
Decreased IOP
Miosis
What drug is very helpful in emergency situations of glaucoma
Prostaglandin Analogs like Latanoprost (Xalatan)
causes significant decrease in IOP
works in 15-20 min
How do Prostaglandin Analogs like Latanoprost (Xalatan) affect cats
Cats dont have the receptors … minimal IOP decrease but will cause miosis
What species is Prostaglandin Analogs like Latanoprost (Xalatan) not helpful in decrease IOP
Cats and horses
Dont use Prostaglandin Analogs like Latanoprost (Xalatan) if
1) Significant uveitis is present
2) Anterior lens luxation (good if posterior lens luxation)
T/F: Prostaglandin Analogs like Latanoprost (Xalatan) is good for anterior lens luxation
False - it is contraindicated
excellent for POSTERIOR lens luxation
What color top is Prostaglandin Analogs like Latanoprost (Xalatan)
Light blue
What is an example of a Prostaglandin Analog for glaucoma
Latanoprost (Xalatan)
increases aqueous outflow and may also decrease production
Latanoprost (Xalatan) causes
-Miosis
-Decreased IOP
(uveitis)
Rank the glaucoma medications by strength of glaucoma treatment in dogs
Mild: Timolol
Moderate: Dorzolamide, Dorzolamide / Timolol
Strong: Latanoprost
What are the 3 mydriatic agents
1) Tropicamide
2) Phenylephrine
3) Atropine
What is the mechanism of Tropicamide
Parasympatholytic - Anticholinergic
causes temporary dilation (best for fundic exams)
onset 15-20 min
duration: 305 hours
Tropicamide is indicated for
causes temporary dilation (best for fundic exams)
onset 15-20 min
duration: 3-5 hours
What is the mechanism of phenylephrine
sympathomimetic - alpha adrenergic
can also induce tachycardia and elevate systemic blood pressure
What are the side effects of Phenylephrine
can also induce tachycardia and elevate systemic blood pressure (sympathomimetic - alpha adrenergic )
What are the indications of phenylephrine
1) Reduce conjunctival hemorrhage during ocular surgery (blanch gums)
2) Confirm 3rd order Horner’s syndrome after denervation
What should you tell the anesthesiologist when giving phenylephrine
that the mouth and gums might be blanched
What is the mechanism of topical atropine
parasympatholytic - anticholingeric
What is the strongest mydriatic agent
Atropine (onset is 30 min but duration is 7-10 days)
What are the side effects of topical atropine
1) Decrease tear production (caution KCS)
2) Decrease gut motility in horses
What are the indications of Atropine
1) Excellent cycloplegic (effective for uveitis pain control associated with ciliary body spasm)
Red top tubes are contraindicated if
the patient has IOP
all dilating drops can increase IOP
What should you remember when administering red topped tubes (mydriatic agents)
1) Will dilate pupils (wash hands)
2) Check IOP before administering
What tube color are the mydriatic agents such as Tropicamide, Atropine, and Phenylephrine
Red
What are the different types of calcineurin inhibitors
1) Cyclosporine
2) Tacrolimus
Calcineurin inhibitors like cyclosporine and tacrolimus are primarily used to treat
KCS, however can also be used for some immune mediated diseases (eg Pannus)
What two drugs can be combined for bad KCS
Cyclosporine and Tacrolimus
What is a good medication if the patient is sensitive to Cyclosporine
Tacrolimus
What are the different versions of Cyclosprine
1) Optimmune: 0.2%- ideal for mild KCS (ointment)
2) Compounded in 1 and 2% for worse KCS (solution that last longer)
What are the side effects of calcineurin inhibitors like Cyclosporine and Tacrolimus
1) Increases risk of corneal SCC in cases of chronic use and active keratitis
2) Immune suppressive- use gloves or handwashing after use
