Pharmacology

Question 1

Ocular barriers to drugs

Answer 1

Tear film (dilutes)
Cornea (hydrophobic epithelium/hydrophilic stroma)
Blood eye barrier

Question 2

Topical drugs

Answer 2

Ocular surface to posterior lens capsule

Question 3

Systemic medication

Answer 3

Lids, orbit, posterior segment, perforated globe

Cannot use for cornea (no blood vessels)

Question 4

Requirements for topical drugs

Answer 4

Lipiphilic, hydrophilic, small

Question 5

What happens in regards to topical meds if the epithelium is removed?

Answer 5

Typically better drug penetration

Question 6

How much of a topically administered drug will enter the anterior chamber?

Answer 6

1-10%

Question 7

Proparicaine HCL 0.5%

Answer 7

Topical anesthetic
Cannot be used as therapy
Delays healing, up regulates pain receptors, causes ulceration

Question 8

Tropicamide 1%

Answer 8

Short acting Mydriatic for exams

No pain relief

Question 9

Atropine 1%

Answer 9

Long acting 
Pain relief
Prevents posterior synechia
Stabilizes blood-aqueous humor
Prevents drooling
Can exacerbate low tear production

Question 10

Chloramphenicol 0.5% sol or 1% ointment

Answer 10

Topical antibiotic
Cat conjunctivitis (chlamydophila/mycoplasma)
Septic keratitis/conjunctivitis with cocci

Question 11

Tetracyclines (doxy, Terramycin, azithromycin)

Answer 11

Cat conjunctivitis

Topical antibiotic

Question 12

Cefazolin 5.5%

Answer 12

Topical antibiotic

Gram positive organisms

Question 13

Amino glycosides

Answer 13

Topical antibiotic
NPB, gentamicin, tobramycin
Good for rods

Question 14

Fluoroquinolones

Answer 14

Topical antibiotics (big guns) 
Prevents DNA from unwinding

Question 15

Fluoroquinolones 1st gen

Answer 15

Primarily gram neg rods

Nalidixic acid relatives

Question 16

Fluoroquinolones 2nd generation

Answer 16

Ciprofloxacin ofloxacin, levofloxacin
Gram neg, gram pos
Septic keratitis with rods, cat conjunctivitis
Nt a 1st choice drug

Question 17

3rd generation fluoroqinolnes

Answer 17

Some gram neg, improved gram pos

Question 18

4th generation fluoroquinolones

Answer 18

Gram neg, good gram pos
Moxifloxacin, gatifloxacin
Less likely to develop resistance

Question 19

Autologous plasma/serum

Answer 19

Use for melting corneal ulcers
Lasts 2-3 days
I drop topically q1-4h

Question 20

Oxytetracycline topical, oral doxy, acetylcysteine +EDTA

Answer 20

Melting ulcer (anti protease)

Question 21

Topical anti fungal

Answer 21

Used almost exclusively for equine corneal fungal infections 
Natamycin 5%
Itraconazole
Miconazole (can be irritating topically)
Voriconazole 
Fluconazole

Question 22

Antivirals (topical)

Answer 22

Trifluridine
Idoxuridine

Cidofovir

Question 23

Systemic antivirals

Answer 23

L-lysine

Famcyclovir- can be toxic, follow with cbc and chem panels

Question 24

Neo/poly/dex

Answer 24

A corticosteroid plus antiinflammatories

Cheaper than dex alone

Question 25

Prednisolone acetate

Answer 25

Corticosteroid (topical) may have better penetration than npdex

Question 26

Systemic steroids

Answer 26

Necessary for posterior disease | Must rule out infectious causes

Question 27

Side effects of topical steroids

Answer 27

``` Delay corneal wound healing DO NOT USE if ulcerated cornea Reactivation of herpes keratitis Lipid deposits in cornea Iatrogenic cushings ```

Question 28

NSAIDs

Answer 28

``` Flurbiprofen sodium, diclofenac Traumatic inflammation Surface analgesic Usu q8-12 hours Use instead of steroids if lipid keratopathy present Caution in hyphema ```

Question 29

Glaucoma meds

Answer 29

Goal to keep IOP in safe range | Target aqueous production or aqueous outflow

Question 30

Mannitol

Answer 30

Hyperosmotic diuretic Pre op lens luxation Big drop in IOP (short lived) Additive to other glaucoma drugs

Question 31

Latanoprost

Answer 31

``` Lowers IOP PGF derivative (unoprostone, travoprost, bimatoprost) Not used in cats, doesn't work Intense miotic in dog and cat Additive to all other glaucoma meds ```

Question 32

Carbonic anhydrase inhibitors (methanol aimed, dorsal aimed, timolol, brinzolamide)

Answer 32

``` Glaucoma meds Decrease aqueous humor production Topicals have a lower toxicity Systemic causes metabolic acidosis Safe for all types of glaucoma ```

Question 33

Cholinergics

Answer 33

``` Glaucoma meds (3rd choice) Doesn't work well Contracts ciliary muscle Painful Additive to every class glaucoma meds ```

Question 34

Beta adrenergic blockers

Answer 34

3rd choice in secondary glaucomas or as prophylactic Decreases aqueous production May increase outflow in dogs and cats Additives to other classes except beta agonists

Question 35

KCS treatments

Answer 35

Cyclosporine a | Tacrolimus

Question 36

Artificial tears mucin deficiency

Answer 36

Cyclosporine Polyvinyloyrroldine Methylcelluloses

Question 37

Artificial tears lipid deficiency- blepharitis

Answer 37

Oil based Refresh, endure, soothe Sodium hyaluronate Warm compresses x5 min

Question 38

Feline conjunctivitis treatment

Answer 38

Topical antibiotics- | Tetracyclines, etprythromycin, cipro, chloramphenicol

Question 39

Treatment for corneal erosions

Answer 39

Topical antibiotics | Neo-poly-bac routinely used

Question 40

Treatment for infected corneal ulcers

Answer 40

``` Topical antibiotics- aminogoycosides- gentamicin, tobramycin Or Fluoroquinolones- cipro, ofloxacin, etc Combo with cefazolin Systemic AB won't help ```