Pharmacology

Question 1

Epithleium and stroma, which is lipophilic?

Answer 1

Epithelium is lipophilic/hydrophobis

Stroma is lipophobic/hydrophilic

Question 2

What is special about chloramphenicol?

Answer 2

It has both lipophilic and hydrophilic properties and penetrates cornea

Question 3

How can you modify steroids?

Answer 3

Alcohol or acetate makes steroid more hydrophobic

Phosphate makes it more hydrophilic

Question 4

Prednisolone acetate

Answer 4

hydrophobic
Good penetration in uninflamed cornea
Used post-operatively

Question 5

Prednisolone phosphate

Answer 5

Hydrophilic
Poor penetration in uninflamed cornea
Used for cornea disease or when want low dose steroids

Question 6

What is benzalkonium?

Answer 6

Benzalkonium is a preservative.
Also disrupts lipid layer of tear film
Aids penetration of some drugs

Question 7

Acute angle-closure glaucoma and IOP

Answer 7

In acute angle-closure glaucoma, the intraocular pressure rises rapidly because the iris blocks the angle in the front of the eye where the anterior chamber fluid normally drains out.

Question 8

Drug used to lower IOP in glaucoma?

Answer 8

Bimatoprost

Question 9

Systemic absorption of topical drugs

Answer 9

Tears are pumped out of lacrimal sac rapidly
Excess gains systemic absorption at nasopharynx
Limited by punctal occlusion

Question 10

How do you stop excess drug getting absorbed at nasopharynx?

Answer 10

Punctal occlusion e.g. sticking your fingers in your eyes

Question 11

Routes of administration for drug into eyes?

Answer 11

Subconjunctival and subtenons

Subconjunctival
(prevents from exiting from tear film, but painful)

Subtenons
(don’t have to use needle, make cut and put in canula to get to back of eye. How you give local anaesthtic for surgery. Procedure is much less painful but only good for back of the eye)

Question 12

Ocular Injetions

Answer 12

Intravitreal
(injecting into vitreous cavity, gets to macula. Have to be carfeul so you don’t hit retina –> retinal detachment)
Intracameral
(safer but more difficult, put needle through cornea –> anterior cavity)

Question 13

Main antibiotic used in eye infections?

Answer 13

Chloramphenicol

Question 14

Side effects of chloramphenicol?

Answer 14

Allergy
Irreversible aplastic anemia
Grey baby syndrome (not for topical, only for systemic chloramphenicol)

Question 15

Which antibiotic inhibits peptidyl transferase?

Answer 15

Chloramphenicol

Question 16

Chloramphenicol

Answer 16

Most commonly used topical antibiotic
Ointment or drops
Inhibits peptidyl transferase enzyme (therefore stops bacterial protein being made)
Bacterocidal for strep and haemophilus
Bacterostatic for staph

Question 17

Give an example when you would not use chloramphenicol?

Answer 17

Corneal ulcer

Question 18

Antibiotic that inhibits protein synthesis?

Answer 18

Chloramphenicol

Question 19

Talk to me about ofloxacin?

Answer 19

Inhibits DNA synthesis

Ofloxacin is a quinolone

Question 20

Why do you like the beta lactam ring?

Answer 20

It inhibits the enzyme which makes bacterial cell wall?

Question 21

Which antibiotics have a common B lactam ring?

Answer 21

Penicillins and cephalosporins

Question 22

How would you treat corneal ulcer?

Answer 22

Anti-virals e.g. Zovirax

DO NOT USE STEROID DROPS

Question 23

What does zovirx mimic?

Answer 23

Zovirax mimics guanine

Question 24

When might you see Keratoprecipitates?

Answer 24

You might see keratoprecipitates in inflammation

They are remnants of WBC or something

Question 25

When are steroids used in the eye?

Answer 25

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

Question 26

What type drugs could you use: Post op cataratcs Uveitis To prevent corneal rejection

Answer 26

Steroids

Question 27

Side effects of steroids

Answer 27

``` cataract glaucoma exacerbation of viral infection Gastric ulceration Immunosuppression Osteoporosis Weight gain Diabetes Neuropsychiatric effects ```

Question 28

Eye side effects of steroids?

Answer 28

Cataract Glaucoma Exacerbation of viral infection

Question 29

Strength of topical steroids

Answer 29

FML Predsol Betamathasone Dexamethasone/ prednisolone

Question 30

Other inflammatory agents

Answer 30

Antihistamines and mast cell stabilisers used in hayfever / allergic conjunctivitis NSAIDS can be used for pain relief eg post refractive laser

Question 31

Drug you might give for pain relief e.g. post refractive laser?

Answer 31

NSAID

Question 32

Glaucoma medication

Answer 32

Bimatoprost Prostanoids eg Latanoprost (‘Xalatan’). (don’t need to know_ 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 33

Risk with intravitreal drugs?

Answer 33

Many drugs are toxic to retina

Question 34

How would you deliver antibiotics in endopthalmitis?

Answer 34

Intravitreal

Question 35

How would you deliver intra-ocular steroids or anti-VEGF?

Answer 35

Intravitreal

Question 36

Local anaesthetic in eyes

Answer 36

Blocks sodium channels and impedes nerve conduction Used extensively in ophthalmology for 1) FB removal 2) Tonometry (IOP measurement) 3) corneal scraping 4) comfort

Question 37

Diagnostic dyes e.g. fluroscein

Answer 37

Uses 1) shows corneal abrasion 2) tonometry 3) diagnosing nasolacrimal duct obstruction 4) angiography

Question 38

Mydriatics

Answer 38

E.g. tropicamide, cyclopentolate (short acting 2-3 hours) Cause pupil dilation by blocking parasympathetic supply to iris Side effects – blurring, AACG

Question 39

Side effects of mydriatics?

Answer 39

Blurring, AACG

Question 40

Anterior ischemic neuropathy

Answer 40

Rapid, painless loss of vision in affected eye but may affect upper or lower field only (altitudinal defect) Vision usually significantly impaired (counting fingers or less) Disc swelling with haemorrhages around the posterior pole No visual recovery

Question 41

Glaucoma

Answer 41

The glaucomas are generally related to reduced outflow of aqueous humor through the trabecular meshwork of the anterior chamber or iridocorneal angle

Question 42

Complication of intra-vitreal injection? (e.g. anti-VEGF)

Answer 42

Endopthalmitis (extreme inflammation)

Question 43

Which channels are blocked in a local anaesthetic injection in the eye?

Answer 43

Sodium channels blocked

Question 44

What might you use to diagnose a nasolacrimal duct obstruction?

Answer 44

A diagnostic dye

Question 45

Tropicamide, cyclopentolate?

Answer 45

Mydriatic drugs | Act on the parasympathetic system to dilate the eye

Question 46

Phenylephrine, atropine

Answer 46

Sympathomimetics

Question 47

Vigabatrin side effect?

Answer 47

Constricts visual fields | Not reversible

Question 48

Side effect of ethambutol?

Answer 48

Optic neuropathy

Question 49

Side effect of chloroquine?

Answer 49

Maculopathy

Question 50

Side effect of chloramphenicol?

Answer 50

Allergy Irreversible aplastic anaemia Grey baby syndrome

Question 51

Anti-inflammatory agents used in eye problems

Answer 51

Steroids Topical NSAIDs Anti-histamines Mast cell stabilisers

Question 52

Latanoprost

Answer 52

Prostaglandin inhibitor

Question 53

Tinolol, betaxolol, levobunolol, carteolol

Answer 53

Beta blockers

Question 54

Dorzolamide (topical) | Acetazolamide (systemic)

Answer 54

Carbonic anhydrase inhibitors