Drugs - Ophthalmology

Question 1

What does ‘g’ denote?

Answer 1

Drops

Question 2

What does ‘oc’ denote?

Answer 2

Eye ointment

Question 3

Give some ophthalmologic indications for chloramphenicol

Answer 3

1. Severe cases of bacterial conjunctivitis
2. Prophylaxis against 2ary infection in corneal abrasions, post foreign body removal, post-operative, chemical eye injury

Question 4

Give an otologic indication for chlormaphenicol

Answer 4

Otitis externa

Question 5

Why is systemic chloramphenicol rarely used?

Answer 5

Due to its severe toxicity

Question 6

What is a potential serious side effect of systemic chloramphenicol?

Answer 6

Bone marrow suppression

Question 7

Why is chloramphenicol contraindicated in the 3^rd trimester of pregnancy, breastfeeding & children <2 years?

Answer 7

Due to risk of grey baby syndrome

Question 8

Give an ophthalmologic indication for oc aciclovir

Answer 8

HSV corneal ulcers

Question 9

Give an ophthalmologic indication for oral aciclovir

Answer 9

Ophthalmic shingles

Question 10

What class of drug is pilocarpine?

Answer 10

Miotic

Question 11

What is the function of miotics?

Answer 11

Produce contraction of the iris sphincter muscle and ciliary muscle → constrict pupils

Question 12

What is the mechanism of miotics?

Answer 12

Produces contraction of the iris sphincter muscle and ciliary muscle by mainly stimulating muscarinic receptors.

Question 13

Main indication of pilocarpine?

Answer 13

Acute angle closure glaucoma → to reduce intraocular pressure

Question 14

What are mydriatic drugs/cytoplegic drugs?

Answer 14

Mydriatic → dilate pupils

Cytoplegic → paralyse ciliary muscles

Question 15

Give some examples of mydriatic drugs

Answer 15

• Atropine
• Cyclopentolate
• Tropicamide
• Phenylephrine

Question 16

What class of drugs are Atropine, Cyclopentolate, Tropicamide, Phenylephrine?

Answer 16

Antimuscarinics

Question 17

Which 2 drugs are most commonly used as dilating agents in fundoscopy?

Answer 17

• Phenylephrine
• Tropicamide

Question 18

Give some indications for mydriatics/cytoplegics

Answer 18

• Dilating agent in fundoscopy
• Symptomatic pain relief e.g anterior uveitis, chemical eye injuries etc

Question 19

How does atropine or cyclopentolate provide symptomatic pain relief?

Answer 19

by paralysing the iris and helping to reduce ocular pain

Question 20

Mechanism of mydriatrics/cycloplegics?

Answer 20

• Block the action of ACh on the iris sphincter muscles and ciliary body.
• This dilates the pupil and reduces pain associated with ciliary spasm by stopping the action of the ciliary body

Question 21

What can the use of mydriatris be a risk factors for?

Answer 21

Acute angle closure glaucoma due to dilation of the pupil

Question 22

What is the most commonly used steroid in ophthalmology?

Answer 22

Prednisolone 1%

Question 23

Indications for prednisolone in ophthalmology?

Answer 23

Inflammatory conditions of the eye e.g. uveitis, severe cornea ulceration, post-op

Question 24

Give 2 examples of topical beta blocker eye drops

Answer 24

1. Timolol 0.5%
2. Betaxolol

Question 25

Indication for timolol?

Answer 25

Used to **reduce intraocular pressures** by reducing aqueous production e.g. chronic/primary open angle glaucoma

Question 26

How do topical beta blocker eye drops reduce intraocular pressure?

Answer 26

Reduce aqueous production

Question 27

Give 2 examples of prostaglandin analogues

Answer 27

1. Latanoprost 2. Bimatoprost

Question 28

What is the 1st line agent to **reduce intraocular pressures** in chronic/1ary open angle glaucoma?

Answer 28

Latanoprost

Question 29

Why are prostaglandin analogues generally preferred over topical beta blockers in ocular hypertension?

Answer 29

as they cause fewer systemic side effects

Question 30

Mechanism of prostaglandin analogues?

Answer 30

Analogues of prostaglandin reduce intraocular pressure by **increasing outflow of aqueous humour** via the **uveoscleral pathway**

Question 31

Side effects of prostaglandin analogues?

Answer 31

* Locally in the eye – blurred vision, conjunctival reddening (hyperaemia), ocular irritation and pain * May cause a **permanent change in eye colour** by increasing the amount of **melanin** in stromal melanocytes of the iris (not harmful) * This affects about 1/3 patients and is most noticeable when treatment is restricted to one eye

Question 32

What is aphakia?

Answer 32

Absent lens

Question 33

What is pseudophakia?

Answer 33

Artificial lens

Question 34

What class of drug is **Brimonidine** eye drops?

Answer 34

Sympathomimetics

Question 35

Purpose of sympathomimetic drugs?

Answer 35

Topical sympathomimetics **reduce** **intraocular** **pressure**

Question 36

How do sympathomimetics reduce intraocular pressure?

Answer 36

By **decreasing** **aqueous humour production** by an effect on ciliary epithelium and **increasing uveoscleral outflow** of aqueous humour.

Question 37

Mechanism of sympathomimetics?

Answer 37

Stimulant compounds which mimic the effects of endogenous agonists of the sympathetic nervous system.

Question 38

What class of drug is acetazolamide?

Answer 38

Carbonic anhydrase inhibitor

Question 39

Main indication of acetazolamide?

Answer 39

Used to **reduce intra-ocular pressures** in _open_ angle glaucoma/2ary glaucoma or peri-operative in angle-closure glaucoma

Question 40

How does acetazolamide reduce intraocular pressure?

Answer 40

By reducing the production of **aqueous humour**

Question 41

Give some examples of ocular lubricants

Answer 41

* oc. **lacrilube** * g. **celluvisc** * g. **Hypromellose**

Question 42

Indications for ocular lubricants?

Answer 42

Used to **increase ocular lubrication** in conditions that may cause dry eyes or ocular surface irritation e.g. **dry** **eyes**, **blocked** **nasolacrimal** **duct**, **blepharitis**, **thyroid eye disease**, **allergic** **conjunctivitis**