pharmacology

Question 1

what are 4 routes of eye administration

Answer 1

topical, subconjunctival, subtenons and ocular injection

Question 2

are the ocular epithelium of the cornea (outside) and the ocular stroma of the cornea (middle) hydrophobic/ hydrophilic respectively

Answer 2

ocular epithelium = hydrophobic/ lipophilic (lipophillic drugs penetrate

ocular stroma = hydrophilic/ lipophobic (hydrophillic drugs penetrate)

Question 3

inflammation reduces the hydrophobic/ hydrophilic nature of the endothelium

Answer 3

inflamm reduces the hydrophobic nature of endothelium

Question 4

what can the lipid tear layer do to drug penetration

Answer 4

reduce it

Question 5

what drug is both lipophilic and hydrophilic and so can penetrate both layers of the cornea well

Answer 5

chloramphenicol

Question 6

what is added to a steroid to make it hydrophobic? what are they used for and give an example

Answer 6

alcohol or acetate / passes through cornea so good for cataracts or post op in uniflammed eye / prednisolone acetate

Question 7

what is added to a steroid to make it hydrophillic? what are they used for and give an example

Answer 7

phosphate / stays on surface of eye - good in inflamed eye and cornea disease / prednisolone phosphate

Question 8

what strengths of ocular steroids are there (mild –> strong)

Answer 8

FML –> predsol (pred phosphate) –> betamethasone –> dexamthasone/ pred acetate

Question 9

when are topical steroids used (3)

Answer 9

post op cataracts, uveitis, protect corneal graft rejection

Question 10

what are local and systemic side effects of steroids

Answer 10

cataract, glaucoma, exac viral infection - GI upset, osteoporosis, weight gain, diabetes

Question 11

when must topical steroids NEVER be given and why

Answer 11

viral keratitis as can cause corneal melting

Question 12

what agents can be added to drugs to enhance corneal penetration

Answer 12

benzalkonium (disrupts teat film) and Bimatoprost (glaucoma)

Question 13

what antibiotics are used in eye infections

Answer 13

chloramphenicol, gent, ofloxacin

Question 14

what antiviral is used in eye infections

Answer 14

zorivax

Question 15

what is the aim of glaucoma treatment and by what mechanisms fo they work

Answer 15

reduce IOP - decreased production of fluid AND/ OR increase fluid outflow/ drainage from trabecular network

Question 16

what main drug classes are used in glaucoma (5)

Answer 16

prostanoids, B blockers, carbonic anhydrase inhibitors, A2 agonist, parasympathetics/ miotics

Question 17

what is the first line drug for glaucoma and what does it do

Answer 17

prostanoids eg latanoprost (xalatan) - opens uvea-scleral outflow (drainage)

Question 18

give an example of a betablocker and how they work in glaucoma

Answer 18

timolol - block ciliary body (decrease fluid production)

Question 19

give an example of a carbonic anhydrase inhibitor and how they work in glaucoma

Answer 19

dorzolamide - reduce production of aqueous humour (side effects)

Question 20

give an example of a parasympathetic/ miotic and how they work in glaucoma

Answer 20

contracts pupil to increase drainage - used in closed angle

Question 21

what drug is commonly used in open angle glaucoma and how does it work

Answer 21

A2 agonist eg brimonidine - makes vessels leakier to increase drainage

Question 22

when would intravitreal administration be used and why is it dangerous

Answer 22

antibiotics in endophthalmitis and intra-ocular steroids - many drugs toxic to retina

Question 23

how does local anaesthetic work in the eye and when is it used

Answer 23

blocks Na channels to stop nerve conduction - FB removal / tonometry/ corneal scraping/ surgert

Question 24

what diagnostic eye is used in ophthalmology and what is it used for

Answer 24

fluorescein - corneal abrasion/ dentritic ulcer/ leaks/ tonometry

Question 25

what effects to mydriatics have on the eye and what are some side effects

Answer 25

cause pupil dilation by blocking parasympathetic supply to iris - blurring and acute glaucoma

Question 26

name 2 mydriatics

Answer 26

tropicamide and cyclopentolate

Question 27

what drug causes colour blindness as a side effect

Answer 27

digoxin

Question 28

what drug causes white streaks across pupil as a side effect

Answer 28

amiodarone

Question 29

what drug causes red tears as a side effect

Answer 29

rifampicin

Question 30

what drug causes maculopathy as a side effect

Answer 30

chloroquine

Question 31

what drug causes optic atrophy as a side effect

Answer 31

alcohol