Drugs For Glaucoma

Question 1

Open Angle Glaucoma
Topical drugs

Answer 1

Beta adrenergic blockers
Alpha adrenergic agonists
Prostaglandin analogues
Carbonic anhydrase inhibitors
Miotics

Question 2

Beta adrenergic blockers

Answer 2

Timolol
Betaxolol
Levobunolol
Carteolol

•No effect on pupil size,tone of ciliary muscle or outflow
•Reduces aqueous formation-by down regulation of adenylcyclase(beta 2 receptor blockade)
Secondary effect- reduction in ocular blood flow
•systemic S.E. due to absorption through nasolacrimal duct

Question 3

Receptors

Answer 3

•Alpha 1-ciliary blood vessels
Vasoconstriction +reduce aqueous production
•Aplha 2-ciliary epithelium
Reduce aqueous secretion
•Beta 2-ciliary epithelium
Enhance aqueous secretion via Inc cAMP
•Carbonic Anhydrase-ciliary epithelium
Generated HCO3- secreted in aqueous humor

Question 4

TIMOLOL

Answer 4

Non selective (beta 1 & 2)
Lasts for ~12 hrs(fall in iot within 1 hr)
High level of clinical safety compared to pilocarpine

Question 5

BETAXOLOL

Answer 5

Beta1 selective
Protective effect on retinal neurons + iot lowering effect
Ocular beta receptors (mainly beta2)
Less efficient

Question 6

LEVOBUNOLOL

Answer 6

Once daily alternative to timolol

Question 7

DIPIVEFRINE

Answer 7

Prodrug of Adr
Penetrates cornea—>hydrolysed by esterase—> form Adr
Adr—>augment uveoscleral outflow
Dec aqueous formation
Only add on therapy

Question 8

APRACLONIDINE

Answer 8

Dec aqueous production (primarily aplha1)

Question 9

BRIMONIDINE

Answer 9

Alpha 2 selective
Dec aqueous production,Inc uveoscleral flow
Prophylaxis of iot spikes post laser/surgery

Question 10

LATANOPROST

Answer 10

Reduces iot in normal glaucoma
Efficient, once daily, no systemic side effects—> first choice drugs but high cost

Question 11

TRAVOPROST

Answer 11

Selective FP prostanid receptor agonist
Inc uveoscleral outflow+ minor effect on trabecular outflow

Question 12

BIMATOPROST

Answer 12

Synthetic
More than or same effective as latanoprost

Question 13

ACETAZOLAMIDE

Answer 13

Oral(0.25 g 6-12 hrly)
Dec aqueous production

Question 14

DORZOLAMIDE

Answer 14

2% eye drops BD-TDS
Less efficient than timolol
Only used as add on drug to beta blocker/PG

Question 15

MIOTICS

Answer 15

Last option drugs
Inc ciliary muscle Toney improving potency of trabeculae

Question 16

Treatment plan

Answer 16

•Start with monotherapy with LATANOPROST/other PG and/or topical beta blockers
•if target iot not attained—>change to alternative drugs or use both concurrently
•if contradiction to PG/beta blocker—>Give BRIMONIDINE/DORZOLAMIDE(occationly Dipivefrine)
•Last option drugs—>TOPICAL MIOTICS & ORAL ACETAZOLAMIDE

Question 17

Angle closure glaucoma

Answer 17

Narrow iridocorneal angle+ narrow anterior chamber
Sudden rise in iot ,if not lowered will lead to vision loss

Question 18

Therapy

Answer 18

1.HYPERTONIC MANNITOL(20%) or GLYCEROL(10%)—> i.v
2.ACETAZOLAMIDE(0.5g)—>i.v followed by orally BD
3.MIOTIC- when iot starts falling then give pilocarpine 1-4% every 10 mins initially
4.TOPICAL BETA BLOCKER- Timolol 0.5%
5.APRACLONIDINE(1%)/LATANOPROST 0.005%
Drugs terminate the attack

Definitive treatment-surgical or laser iridotomy