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Ophthalmology Week 2 2017/18 > 3: Pharmacology > Flashcards

Flashcards in 3: Pharmacology Deck (32)
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1

How are drugs administered in ophthalmology?

Topically

2

Hydrophilic drugs cannot pass through the ___.

Hydrophobic drugs cannot pass through the ___.

epithelium because they're not lipid-soluble

stroma because they're not water-soluble

3

The epithelium of the cornea is ___.

The stroma of the cornea is ___.

The endothelium of the cornea is ___.

(hydrophilic / hydrophobic)

hydrophobic

hydrophilic

hydrophobic

like a big water sandwich

4

Which drugs can pass through the epithelium?

Which drugs can pass through the stroma?

Hydrophobic i.e lipid-soluble

Hydrophilic i.e water-soluble

lipid : water : lipid

5

Which type of drug easily penetrates the hydrophobic epithelium of the cornea?

Hydrophobic

i.e lipid-soluble drugs

6

Which type of drug easily penetrates the hydrophilic stroma of the cornea?

Hydrophilic

i.e water-soluble

7

Which topical antibiotic has both hydrophobic and hydrophilic properties?

Chloramphenicol

so it can pass straight through epithelium AND stroma

8

How are steroids made more hydrophobic?

What layer does this let them pass through?

ALCOHOL or ACETATE

Epithelium

9

How are steroids made more hydrophilic?

Which layer does this let them pass through?

PHOSPHATE

Stroma

10

What is added to topical drugs to act as a preservative?

Benzalkonium

11

How are topical eye drugs absorbed into the systemic circulation?

Inferior lacrimal papillae > Punctua > etc

12

Apart from topically, how else are eye drugs administered?

Subconjunctival injection

Subtenons (a surface under the conjunctiva)

Intravitreal (into the posterior chamber through the side)

Intracameral (into the front of the eye)

13

How are eye infections treated?

Topical antibiotics

Topical antivirals

14

How is eye inflammation treated?

Topical steroids

Topical NSAIDs

Topical anti-histamines

Mast cell stabilisers

15

What are some situations for which you'd give a patient topical steroids?

After cataract surgery

Uveitis

After corneal graft to prevent rejection

16

What type of vasculitis, associated with polymyalgia rheumatica, can cause sudden onset headache and eventually visual loss due to infarction?

How is it treated?

Giant cell / temporal arteritis

Immediate oral prednisolone (dose depends on whether or not there's visual symptoms)

17

What are the specific eye side effects of steroids?

Cataracts

Glaucoma

Infection risk

18

What is glaucoma?

Which visual field goes first?

Progressive optic nerve damage (sometimes due to raised intraocular pressure)

Peripheral vision

(Visual acuity is retained i.e they can see down the chart but their peripheries are gone)

19

What is the only known risk factor for glaucoma?

Raised intraocular pressure

doesn't mean that everyone with glaucoma has raised intraocular pressure

20

What is the principle of glaucoma treatment?

Lower intraocular pressure to reduce progression of symptoms

You can't stop the progression but you can slow it down

21

What types of drug are used to treat glaucoma?

Prostanoids ("open outflow system")

Beta blockers (e.g timolol, side effects, block ciliary body to reduce aqueous production)

Carbonic anhydrase inhibitors (e.g dorzolamide, same mechanism as beta blockers, side effects)

Alpha agonists (open outflow system and block ciliary body, high rate of allergy)

 

22

slide 42

fluorescein injected, shows new blood vessels at macula

growth from corroid

WET ARMD

23

What are always given alongside intravitreal injections?

Why?

Antibiotics

Iatrogenic endophthalmitis almost always causes blindness in that eye

24

Apart from antimicrobials and anti-inflammatories, what other functions do eye drops have?

Diagnostic e.g fluorescein

Local anaesthetic

Dilation e.g tropicamide

25

What drops are put in to see the back of the eye better during examination?

Mydriatic drugs

e.g tropicamide

26

What are the side effects of tropicamide?

Visual blurring

Very rarely acute glaucoma

27

How does tropicamide work?

Blocks parasympathetic supply (sphincter pupillae) to iris - DILATION

Stops lens from focusing - CANNOT ACCOMMODATE

28

What is acute angle-closure glaucoma?

Sudden increase in IOP blocks drainage of aqueous fluid

Red eye, acute headache and vomiting

Very rare side effect of tropicamide

29

What type of drug is pilocarpine?

What disease is it used to treat?

What side effect does it cause?

Parasympathomimetic

Glaucoma

Reduces IOP by constricting pupil, which causes NIGHT BLINDNESS

30

Many topical drugs can cause ___ reactions.

allergic