Pharmacology

Question 1

routes of drug administration for the eye?

Answer 1

topical
subconjunctival
subtenosis (under conjunctiva)
ocular injections e.g. intravitreal and intracameral (anterior chamber)

Question 2

two layers in the cornea

Answer 2

lipid

water layer

Question 3

chemical properties of the epithelium in the cornea

Answer 3

lipophilic/hydrophobic

Question 4

chemical properties of the stroma in the cornea

Answer 4

lipophobic/hydrophilic

Question 5

what parts of the cornea can lipid soluble drugs penetrate?

Answer 5

epithelium

Question 6

what parts of the cornea can water-soluble drugs penetrate?

Answer 6

stroma

Question 7

example of a drug that can penetrate both the epithelium and stroma

Answer 7

chloramphenicol

Question 8

what can ocular surface inflammation cause?

Answer 8

reduce hydrophobia of epithelium

Question 9

what drugs are limited by epithelium

Answer 9

hydrophilic

Question 10

what drugs are limited by stroma

Answer 10

hydrophobic

Question 11

examples of modifiers added to topical steroids to change characteristics

Answer 11

alcohol or acetate

phosphate

Question 12

what does alcohol and acetate do when added to topical steroids?

Answer 12

makes steroids more hydrophobic

Question 13

what does phosphate do when added to topical steroids

Answer 13

makes steroids more hydrophilic

Question 14

examples of steroids used in the eye

Answer 14

• prednisolone acetate= hydrophobic

- prednisolone phosphate= hydrophilic

Question 15

what is benzalkonium chloride

Answer 15

antibacterial agent and preservative that can disrupt the lipid layer of the tear film aiding drug penetration

Question 16

what is benzalkonium chloride added to?

Answer 16

bimatoprost

Question 17

what happens if the dose of benzalkonium chloride is too high?

Answer 17

topical side effects/ allergic reaction with reddening around the eye

Question 18

how can topical drugs be absorbed systemically

Answer 18

tears pumped out of lacrimal sac
systemic absorption at nasopharynx
limited by punctal occlusion (for 5 minutes after administration)

Question 19

examples of anti-inflammatory agents

Answer 19

steroids
topical NSAIDs
antihistamines
mast cell stabilisers

Question 20

when are steroids used?

Answer 20

post-op cataracts (expose self-proteins in the eye to central immune system)
uveitis
prevention of corneal graft rejection (risk of new vessel formation)

Question 21

example of a condition when steroids are immediately needed?

Answer 21

temporal arteritis

Question 22

local side effects of steroids

Answer 22

cataracts
glaucoma
exacerbation of viral infections

Question 23

systemic side effects of steroids

Answer 23

gastric ulcer
immunosuppression
osteoporosis
weight gain
diabetes
neuropsychiatric effects
overall reduced life expectancy

Question 24

when should you never give steroids alone?

Answer 24

hepatic keratitis as needs antiviral cover (dendritic ulcer)

Question 25

glaucoma medication categories

Answer 25

- prostanoid - beta blockers - carbonic anhydrase - alpha2-adrenergic agonists - parasympathomimetic

Question 26

example of prostanoid

Answer 26

latanoprost

Question 27

why are beta blockers used in glaucoma?

Answer 27

inhibit enzyme responsible for producing aqueous

Question 28

examples of beta blockers given in glaucoma

Answer 28

timolol bextaxolol levobunolol carteolol

Question 29

examples of carbonic anhydrase inhibitors

Answer 29

topical dorzolamide | systemic acetazolamide

Question 30

role of alpha2-adrenergic agonists

Answer 30

vasodilators

Question 31

side effect of brimonidine (alpha2-adrenergic agonist)

Answer 31

overwhelming fatigue

Question 32

example of parasympathomimetic

Answer 32

pilocarpine

Question 33

why is compliance an issue

Answer 33

side effects include red eye, dry, odd taste, stings, etc.

Question 34

when are intravitreal injections used?

Answer 34

``` administering antibiotics (endophthalmitis) intra-ocular steroids (diabetic retinopathy, retinal vein occlusion and uveitis) anti-VEGF (wet ARMD, diabetic retinopathy and retinal vein occlusion) ```

Question 35

when is local anaesthetic used in the eye?

Answer 35

foreign body removal tonometry (IOP measure) corneal scraping cataracts

Question 36

what does local anaesthetic have a risk of?

Answer 36

corneal melt

Question 37

how does local anaesthetic impede nerve conduction?

Answer 37

blocks Na+ channels

Question 38

when is the diagnostic dye fluorescein used?

Answer 38

``` corneal abrasion dendritic ulcers identify leaks tonometry nasolacrimal duct obstruction angiography ```

Question 39

examples of mydriatics

Answer 39

tropicamide | cyclopentolate

Question 40

action of mydriatics

Answer 40

``` cause pupil dilation by blocking parasympathetic supply to iris causes cycloplegia (stops lens from focusing) ```

Question 41

side effects of mydriatics

Answer 41

blurring | AACG

Question 42

action of sympathomimetics

Answer 42

cause the pupil to dilate by acting on the sympathetic system (some cause cycloplegia e.g. atropine) and some do not e.g. phenylephrine

Question 43

ocular side effect of vigabatrin

Answer 43

constricts fields

Question 44

ocular side effects of ethambutol

Answer 44

optic nerve stops functioning and appears pale

Question 45

ocular side effect of digoxin

Answer 45

affects ability to judge colour

Question 46

ocular side effect of chloroquine

Answer 46

maculopathy- screening

Question 47

ocular side effect of amiodarone

Answer 47

brown pigmentation at the cornea