drugs

Question 1

ANTI-MUSCARINIC
(tropicamide, cyclopentolate, atropine)

Answer 1

acts on parasympathetic innervation of ciliary body + sphincter pupillary

blocks muscarinic receptor by preventing binding of acetylcholine

produces cycloplegia + mydriasis

Question 2

SYMPATHOMIMETICS (phenylephrine)

Answer 2

acts on sympathetic innervation of dilator pupillae

stimulates sympathetic NS, acts on alpha-1 receptors + invokes response

Question 3

parasympathetic NS neurotransmitter + receptor

Answer 3

major neurotransmitter - acetylcholine

acts on muscarinic receptor

Question 4

sympathetic NS neurotransmitter + receptor

Answer 4

major neurotransmitter - noradrenaline

acts on alpha + beta receptors

Question 5

MYDRIATICS RISKS

Answer 5

inducing ACG attack (1/5000)

blurred vision post instillation - TRO 4-6 hours until vision back to normal

glare - advise sunglasses

Question 6

tropicamide indications

Answer 6

miosis (physiological, age, drug induced - pain meds)

H&S - flashes/floaters, sudden reduction in VA

specific px groups - >60, diabetic, cataract (esp. if referring), monitoring conditions e.g., naevus, drusen

Question 7

tropicamide contraindications

Answer 7

hypersensitivity to tropicamide or any component of preparation

confirmed or suspected angle closure

multi-dose preparations contain benzalkonium chloride - should not be used when soft CLs worn (wait at least 15 mins before reinsertion)

Question 8

tropicamide side effects

Answer 8

ocular - transient stinging + blurring, photophobia, raised IOPs

general - CNS disturbances, dry mouth

Question 9

cyclopentolate refractive indications

Answer 9

under 16s
presenting strabismus in children
family hx squints
unequal/reduced VA in children
variable refraction
suspect latent hyperopes

Question 10

cyclopentolate therapeutic indications

Answer 10

to break synechiae (when dilating anterior uveitis px)

reduce ciliary spasm (reduces pain if had trauma to eye e.g., corneal abrasion)

Question 11

cyclopentolate side effects

Answer 11

ocular side effects - transient stinging + blurring, photophobia, raised IOP, conjunctival hyperaemia/ oedema

general side effects - CNS disturbances, dry mouth, flushing, tachycardia, urinary or GI symptoms

Question 12

cyclo contraindications

Answer 12

hypersensitivity

confirmed or suspected angle closure

Question 13

phenylephrine indications

Answer 13

when monotherapy is insufficient for mydriasis

differentiation between scleritis + episcleritis

Question 14

phenylephrine contraindications

Answer 14

hypersensitivity to phenylephrine

px with cardiac disease, hypertension, aneurysms, asthma, long-standing insulin dependent diabetes, tachycardia

px taking tricyclic antidepressants + antihypertensive agents (beta blockers)

angle closure or narrow angles

Question 15

phenylephrine side effects

Answer 15

ocular - transient stinging + blurring, photophobia, conjunctival allergic reaction, raised IOPs, punctate keratitis

general - tachycardia, palpitations, cardiac arrhythmias, hypertension, HAs

Question 16

10% phenylephrine contraindicated age

Answer 16

contraindicated in children under 12 years and adults over 65 - increased risk of systemic toxicity

Question 17

anaesthetic action

Answer 17

suppress action potentials in excitable tissues by blocking voltage-gated sodium channels which are involved in pain impulse transmission

Question 18

local anaesthetic esters vs amide

Answer 18

esters - proxymetacaine 0.5%, oxybuprocaine 0.4%, tetracaine 0.5/1%

amide - lidocaine 4% with 0.25% fluorescein

Question 19

LIDOCAINE indication, contraindication, side effects

Answer 19

used for measuring IOPs by Goldmann

contraindication - hypersensitivity

ocular side effects - transient stinging + blurring, punctate keratitis (no general)

Question 20

ESTER LOCAL ANAESTHETIC indications, contraindications, side effects

Answer 20

used for short-term procedures (Goldmann, gonioscopy, minor surgery, FB removal, aid ocular exam if px in severe pain)

C/Is - hypersensitivity to ester type anaesthetics, pre-term neonates

side effects - transient stinging + blurring, punctate keratitis, hyperaemia

Question 21

ocular anaesthesia indications

Answer 21

Goldmann/ perkins
gonioscopy
minor surgery
FB removal
blepharospasm - aid ocular exam if px in severe pain
RGP fitting
Schirmer test

Question 22

ADVICE AFTER LOCAL ANAESTHETIC INSTILLATION

Answer 22

re-examine eye after use (check for reaction)
provide note with drug + ADR advice
do not rub eyes (30 mins after)
do not use CLs for 30 mins after

Question 23

LOCAL ANAESTHETIC ADVERSE REACTIONS

Answer 23

delayed healing + tear flow
lower IOP
light headedness
tinnitus