week 2 pharamcology

Question 1

hydrophobic + hydrophilic drugs administer topically to the eye limited by what?

Answer 1

Hydrophilic drugs limited by epithelium

Hydrophobic drugs limited by stroma

Question 2

how are steroids modified to make for hydrophobic/phillic

Answer 2

Alcohol or acetate makes steroid more hydrophobic

Phosphate makes it more hydrophilic

Question 3

give two examples of eye steroids and their uses

Answer 3

Prednisolone acetate:

• hydrophobic:
• Good penetration in uninflamed cornea
• Used post-operatively

Prednisolone phosphate

• hydrophilic
• poor penetration in uninflamed cornea
• Used for cornea disease or when want low dose steroids

Question 4

what are the two functions of benzalkonium in eye drops?

Answer 4

Benzalkonium is a preservative.

Also disrupts lipid layer of tear film ( therefore; Aids penetration of some drugs)

Question 5

how to limit systemic absorption of topical drugs?

Answer 5

punctal occlusion

-as tears are pumped out of lacrimal sac rapidly are drained by nasopharynx

Question 6

when are topical steroids used?

Answer 6

1) post op cataracts
2) uveitis
3) to prevent corneal graft rejection

• work by suppressing inflammation, allergy and immune responses

Question 7

what are the local side effects of steroid

Answer 7

cataract
glaucoma
exacerbation of viral infection

Question 8

what are the systemic side effects of steroid

Answer 8

Gastric ulceration
Immunosuppression
Osteoporosis
Weight gain
Diabetes
Neuropsychiatric effects

Question 9

why can topical NSAIDs be used?

Answer 9

used for pain relief eg post refractive laser eye surgery

Question 10

what can Antihistamines and mast cell stabilisers be used for?

Answer 10

used in hayfever / allergic conjunctivitis

Question 11

what is glaucoma?

Answer 11

A group of diseases characterised by a progressive optic neuropathy resulting in characteristic fields defects. (reduced peripheral vision)

Question 12

what is the only modifiable risk factor for glaucoma

Answer 12

raised IOP

Question 13

how is glaucoma picked up?

Answer 13

Usually asymptomatic.
It is screened for by optometrists
Chronic disease
Usually slowly progressive

Question 14

treatment for glaucoma?

Answer 14

Prostanoids eg Latanoprost (‘Xalatan’).
Beta blockers (timolol, betaxolol, levobunolol carteolol etc)
Carbonic anhydrase inhibitors eg topical eg Dorzolamide (‘Trusopt’) or systemic – acetazolamide (Diamox)
Alpha2 adrenergic agonist Brimonidine (‘Alphagan’).
Parasympathomimetic - pilocarpine

Combination - (dorzolamide and timolol - Cosopt ).

Question 15

what is the treatment for wet macular degeneration?

Answer 15

anti-VEGF [intravitreal]

Question 16

how does local anaesthetic work?

Answer 16

Blocks sodium channels and impedes nerve conduction

Question 17

when is local anaesthetic used?

Answer 17

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

(use in A+E if pain to examine bc treatment will probably require it anyways)

Question 18

what is the most common diagnostic dye used?

Answer 18

fluorescein

Question 19

why/when is fluorescein used?

Answer 19

1) shows corneal abrasion
2) tonometry
3) diagnosing nasolacrimal duct obstruction
4) angiography
5) dendrtiic ulcer
6) identify leak

Question 20

give an example of a mydriatic

Answer 20

tropicamide, cyclopentolate

Question 21

how do mydriatics work?

Answer 21

Cause pupil dilation by blocking parasympathetic supply to iris

Question 22

side effects of mydraitics?

Answer 22

blurring, AACG (sudden onset headache, check eyes)

Question 23

give an example of a sympathomimetic?

Answer 23

phenylephrine, atropine

Question 24

how do Sympathomimetics work?

Answer 24

Acts on sympathetic system
Causes pupil to dilate

Do not affect the ciliary muscle (accomodation)

Question 25

when should steroids never be given?

Answer 25

herpetic keratitis

Question 26

side effect with Vigabatrin

Answer 26

constricts field

Question 27

Pilocarpine what do it do?

Answer 27

constricts pupil

Question 28

side effect of ethambutol

Answer 28

optic neuropathy (colour loss first), may be irreversible

Question 29

chloroquine effect on the eye

Answer 29

worse than HCQ

causes retinopathy

Question 30

amiodarone effect on the eye?

Answer 30

deposits drug in cornea (fine/visually insignificant)

Question 31

what can occur to all the ocular medications we give?

Answer 31

allergy - immeidate or can develop. can take 9 months to go. itchy, red horrible eyes