Pharmacology - Ophthalmology

Question 1

List the main routes of administration of ocular drugs

Answer 1

Topical (drops, ointments)
Subconjunctival
Subtenons
Ocular injection (intravitreal, intracameral)

Question 2

Which type of drug - hydrophilic or lipophilic - can penetrate the ocular epithelium?

Answer 2

Lipophilic (lipid soluble drugs), since epithelium is hydrophobic and lipophilic

Question 3

Which type of drug - hydrophilic or lipophilic - can penetrate the ocular stroma?

Answer 3

Hydrophilic (water soluble drugs), since stroma is hydrophilic and lipophobic

Question 4

Chloramphenicol is both hydrophilic and lipophilic. True/False?

Answer 4

True

Penetrates cornea easily

Question 5

What effect does ocular surface inflammation have on the hydrophobic nature of the ocular epithelium?

Answer 5

Reduces hydrophobic nature

Question 6

Tear film may impede drug penetration. Why?

Answer 6

Lipid layer will impede hydrophilic agents

Question 7

Hydrophilic drugs are limited by epithelium/stroma and lipophilic drugs are limited by epithelium/stroma

Answer 7

Hydrophilic drugs are limited by epithelium and lipophilic drugs are limited by stroma

Question 8

How can topical steroid be made more hydrophobic (what can be added)?

Answer 8

Alcohol (acetate)

Question 9

How can topical steroid be made more hydrophilic (what can be added)?

Answer 9

Phosphate

Question 10

Prednisolone acetate is hydrophilic. True/False?

Answer 10

False

Hydrophobic (contains acetate)

Question 11

Prednisolone phosphate has good penetration. True/False?

Answer 11

False

It is hydrophilic and thus doesn’t penetrate ocular epithelium well (epithelium is hydrophobic)

Question 12

What can be added to a topical drug to increase corneal penetration?

Answer 12

Benzalkonium

Question 13

Give an example of a drug that can be administered through the subconjunctival route

Answer 13

Steroid

Question 14

Give an example of a drug that can be administered through the subtenons route

Answer 14

Local anaesthetic (via cannula)

Question 15

List some anti-inflammatory agents for ocular disease

Answer 15

Steroid
NSAIDs
Anti-histamines
Mast cell stabilisers

Question 16

When are topical steroids usually used for ocular disease?

Answer 16

Post-op cataracts
Uveitis
Prevent corneal graft rejection

Question 17

List some local ocular side effects of steroids

Answer 17

Acute glaucoma
Cataract
Exacerbation of viral infection

Question 18

How do glaucoma drops basically work?

Answer 18

Decrease production of fluid and/or increase fluid outflow/drainage from the eye through the trabecular meshwork

Question 19

Which class of drug is 1st line for glaucoma and how does it work?

Answer 19

Prostanoids - Latanoprost (Xalatan)

Opens up uveal-scleral outflow (makes vessels leakier to allow fluid drainage)

Question 20

How to beta-blockers and carbonic anhydrase inhibitors help in glaucoma?

Answer 20

Block ciliary body and thus decrease fluid production

Question 21

Give an example of a carbonic anhydrase inhibitor

Answer 21

Topical Dorzolamide

Systemic Acetazolamide

Question 22

How do alpha agonists help in glaucoma? Give an example of one

Answer 22

Brimonidine

Make all vessels leakier and thus increase fluid drainage

Question 23

How do parasympathomimetics help in glaucoma? Give an example of one

Answer 23

Pilocarpine

Pull iris tight together to open up trabecular meshwork and enable fluid drainage

Question 24

Name a pro + con of intravitreal drug administration

Answer 24

Deliver effective concn of drug

Can be toxic to retina

Question 25

When is intravitreal drug administration mainly used?

Answer 25

Administering antibiotic in exophthalmitis

Intra-ocular steroids

Question 26

What effect does local anaesthetic have on the eye?

Answer 26

Blocks sodium channels + impedes nerve conduction so can keep eye open

Question 27

Which dye is useful for viewing corneal abrasions?

Answer 27

Fluorescein dye

Question 28

What do mydriatics do? Give an example and side effect

Answer 28

Block parasympathetic supply to iris, causing pupil dilation
Tropicamide
Side effect: blurring, acute glaucoma