Pharmacology

Question 1

What is required from topical drugs applied to the eye?

Answer 1

they need to act on the surface

they need to penetrate the cornea

Question 2

What type of drugs are good for corneal penetration?

Answer 2

LMW drugs

Question 3

How many layers are there in the cornea and what are they?

Answer 3

5 layers
epithelium
Bowman's layer (membrane)
Stroma
Descent's membrane
Endothelium

Question 4

what is the epithelium in terms of hydro/lipo philic/phobic?

Answer 4

lipophilic

hydrophobic

Question 5

what is the stroma? in terms of hydro/lipo philic/phobic?

Answer 5

hydrophilic

lipophobic

Question 6

which layer do lipid soluble drugs penetrate?

Answer 6

the epithelium

Question 7

which layer do water soluble drugs penetrate?

Answer 7

the stroma

Question 8

what type of drugs penetrate the cornea easily?

Answer 8

drugs that have both lipophilic and hydrophilic properties

Question 9

Give an example of a drug that has both lipophilic and hydrophilic properties and penetrates the cornea easily?

Answer 9

chloramphenicol

Question 10

what can reduced the hydrophobic nature of the epithelium?

Answer 10

ocular surface inflammation

Question 11

which layer of the tear film may impede drug penetration

Answer 11

the lipid layer

Question 12

which layer of the cornea limits hydrophilic drugs?

Answer 12

epithelium

Question 13

which layer of the cornea limits hydrophobic drugs?

Answer 13

stroma

Question 14

what properties must topical steroids (for the eye) have?

Answer 14

hydrophobic and hydrophilic capability

Question 15

What is the affect of the addition of alcohol or acetate to a topical steroid?

Answer 15

makes it more hydrophobic

Question 16

what is the affect of the addition of phosphate to a topical steroid?

Answer 16

makes it more hydrophilic

Question 17

is prednisolone acetate hydrophilic or hydrophobic?

Answer 17

hydrophobic

Question 18

does prednisolone acetate have good penetration an uninflamed cornea?

Answer 18

yes

Question 19

When is prednisolone acetate used?

Answer 19

post-operatively

Question 20

Is prednisolone phosphate hydrophilic or hydrophobic?

Answer 20

Hydrophilic

Question 21

Does prednisilone phosphate have good penetration of the uninflamed cornea?

Answer 21

no

Question 22

when is prednisolone acetate used?

Answer 22

Used for cornea disease or when want low dose steroids

Question 23

What preservative can be added to a drug to enhance corneal penetration?

How does it work?

Answer 23

Benzalkonium

disrupts the lipid layer of the tear film

Question 24

What drug is used to lower IOP in glaucoma?

Answer 24

Bimatoprost 0.03%

Question 25

where can drugs applied topically at the eye be systemically absorbed?

Answer 25

at the nasopharynx

Question 26

What are other routs of administration of drugs a the eye? (not topical)

Answer 26

subconjunctival | subtenons

Question 27

What are the 2 types of ocular injections?

Answer 27

intravitreal | intracameral

Question 28

What are some anti-inflammatory agents?

Answer 28

steroids topical NSAIDs Anti-histamines mast cell stabilisers

Question 29

What is the action of steroids?

Answer 29

suppress inflammation, allergy and immune responses

Question 30

In what eye conditions are topical steroids indicated?

Answer 30

post op cataracts uveitis to prevent corneal graft rejections

Question 31

What are some local side effects of topical steroids in the eye?

Answer 31

cataract glaucoma exacerbation of viral infection

Question 32

What are some systemic side effects of steroids?

Answer 32

``` Gastric ulceration Immunosuppression Osteoporosis Weight gain Diabetes Neuropsychiatric effects ```

Question 33

What are the different strengths of topical steroids?

Answer 33

FML Predsol Betamathasone Dexamethasone/ prednisolone

Question 34

When would anti-histamines and mast cell stabilisers be used?

Answer 34

in hay fever / allergic conjunctivitis

Question 35

When would NSAIDs be used?

Answer 35

pain relief post refractive laser

Question 36

What is the only modifiable risk factor in glaucoma?

Answer 36

raised intra-ocular pressure

Question 37

What drugs are used to treat glaucoma?

Answer 37

``` Prostanoids - latanoprost (xalatan) beta blockers (timolol) carbonic anhydrase inhibitors Alpha2 adrenergic agonist Parasympathomimetic ```

Question 38

What is the mechanism of action of prostanoids?

Answer 38

increase aqueous outflow

Question 39

What is the mechanism of action of beta blockers?

Answer 39

reduce aqueous production

Question 40

When are beta-blocker contraindicated?

Answer 40

COPD / ashma / heart block

Question 41

what is the name of a commonly used topical Carbonic anhydrase inhibitor

Answer 41

Dorzolamide - trusopt

Question 42

what is the name of a commonly used oral Carbonic anhydrase inhibitor

Answer 42

acetazolamide - diamox

Question 43

what is the action of Parasympathomimetic drugs and give an example

Answer 43

pilocarpine | improve aqueous outflow and constrict pupil

Question 44

what is the advantage of Intravitreal drug administration?

Answer 44

Delivers effective concentration of drug at target site instantly

Question 45

What is the problem with Intravitreal drug administration

Answer 45

many drugs are toxic to the retina

Question 46

When is Intravitreal drug administration used?

Answer 46

antibiotics in endophthalmitis Used to deliver intra-ocular steroids Anti-VEGF

Question 47

How does topical anaesthetic applied to the eye work?

Answer 47

Blocks sodium channels and impedes nerve conduction

Question 48

When is local anaesthetic used in ophthalmology?

Answer 48

1) FB removal 2) Tonometry (IOP measurement) 3) corneal scraping 4) comfort

Question 49

What is the most comply used diagnostic dye?

Answer 49

fluorescein

Question 50

What is fluorescein used for?

Answer 50

shows corneal abrasions tonometry diagnosing nasolacrimal duct obstruction angiography

Question 51

What are some examples of mydriatics?

Answer 51

tropic amide | cyclopentolate

Question 52

what is the effect of mydriatics and how do they work?

Answer 52

cause pupil dilation by blocking parasympathetic supply to iris

Question 53

What are the side effects of mydriatic drugs?

Answer 53

blurring | AACG

Question 54

What are some examples of Sympathomimetics and what do they do?

Answer 54

phenylephrine, atropine Acts on sympathetic system Causes pupil to dilate

Question 55

what drug is comply associated with Optic Neuropathy

Answer 55

Ethambutol - The TB drugs

Question 56

What drug is associated with maculopathy?

Answer 56

Maculopathy - treats malaria