Ocular pharmacology

Question 1

Explain how the topical method of drug delivery works

Answer 1

Topically administered drugs that need to reach the anterior chamber must go through the cornea. The cornea has three layers; epithelium, stroma and endothelium. For the drug to pass through the epithelium it must be fat-soluble. And for it to pass through the stroma onwards it must be water-soluble. So a drug that is both water and fat-soluble would be ideal in that it would activate itself after absorption.

Question 2

What diseases/infection/problems of the eye usually require intraocular injection?

Answer 2

a local anesthetic of the eye before surgery
steroid depot for some inflammatory ocular disorders
intraocular bacterial infection treated with intraocular antibiotics injected directly into the globe

Question 3

What s/e can long term steroid use have on the eye

Answer 3

steroid-induced cataract

Question 4

What drugs can be used to treat glaucoma?

Answer 4

beta-blockers - topical e.g. timolol
muscarinic (parasympathetic stimulants) - topical e.g. pilocarpine
alpha2 stimulants - topical e.g. brimonidine
prostaglandin derivatives

Question 5

How do beta-blockers work for glaucoma?

Answer 5

they reduce aqueous secretion by inhibiting the action on beta receptors in the ciliary body.

Question 6

What is an anti-inflammatory agent you would use in eyes?

and possible adverse effects?

Answer 6

corticosteroids such as prednisolone, but can cause glaucoma or cataracts with prolonged use and exacerbation of herpes simplex virus.

Question 7

What are common antibiotics to use in eye?

Answer 7

chloramphenicol, gentamicin, ciprofloxacin, fusidic acid

Question 8

What is a common antiviral to use in the eye for herpes virus

Answer 8

aciclovir