glaucoma

1. Drugs for Glaucoma
Dr Harikrishnan A R

2. Introduction
Progressive optic nerve damage
Generally associated with raised IOT
Reducing the secretion of aqueous
humour or promoting its drainage
Major amount of aqueous drains through
trabecular route

3. Types
• Open angle
• Angle closure

5. Open angle glaucoma
• Genetically predisposed degenerative disease affecting the patency of
trabecular meshwork
• IOT rises insidiously and progressively

6. β Adrenergic blockers
• Lower IOT by reducing aqueous humour formation
• Downregulation of adenylyl cyclase in ciliary epithelium – β2 action
• Do not produce miosis
• Less ocular side effects
• Systemic ADRs – bronchospasm, bradycardia, CHF

7. Timolol
• Nonselective
• No local anaesthetic or intrinsic sympathomimetic action
• Ocular hypotensive action begins at 1 hour lasts up to 12 hours

8. Betaxolol
• β1 selective
• Less systemic side effects compared to other β blockers
• Additional protective effect on retinal neurons by blocking Ca channels
• Less IOT lowering
• ADRs – stinging and burning
• Levobunolol  longer duration than timolol

9. α Adrenergic agonists
α1 – constrict ciliary vessels and
reduce aqueous production
α2 – reduce aqueous secretion

10. Dipivefrine
• Prodrug of adrenaline
• Augments uveoscleral outflow, reduce aqueous formation
• Ocular burning and other local side effects

11. Apraclonidine
• Polar clonidine congener
• Primarily α2 action
• Itching, lid dermatitis, follicular conjunctivitis

12. Brimonidine
• α2 selective clonidine congener
• More lipophilic than apraclonidine
• Similar side effects but less frequent

13. Prostaglandin analogues
• PGF2α – low concentration lowers IOT without inducing ocular
inflammation
• Increases uveoscleral outflow
• First choice drugs for open angle glaucoma

14. Latanoprost
• Ocular effects similar to timolol without systemic side effects
• Reduces IOT in normal pressure glaucoma also
• Blurring of vision, increased iris pigmentation

15. Travoprost
• Increases uveoscleral outflow and trabecular outflow
• IOT lowering and side effects similar to latanoprost

16. Bimatoprost
• More effective than latanoprost
• Similar side effects

17. Carbonic anhydrase inhibitors
• Acetazolamide – reduces aqueous formation by limiting generation of
bicarbonate ion in ciliary epithelium, given orally
• Dorzolamide – topically used as add on drug

18. Miotics
• Increases ciliary muscle tone – improving the patency of trabeculae
• Pilocarpine combined with anti ChEs was used till 1970

20. Approach to OAG
• Monotherapy with PG analogues or β blocker
• Target IOT not attained change to alternate drug or combine them
• brimonidine/dorzolamide used when there are CIs
• Topical miotics and oral acetazolamide are only added as last resort

21. Angle closure Glaucoma
• Narrow iridocorneal angle and shallow anterior chamber
• Mydriasis closes the iridocorneal angle  rapid rise in IOT
• Congestion of eyes with severe headache
• Failure to lower IOT  loss of sight

22. Treatment
1. Hypertonic mannitol(20%) – decongest eye by osmotic action
2. Acetazolamide - 0.5g IV followed by oral twice daily
3. Miotic - pilocarpine 1-4% instilled every 10 min
4. Topical β blocker – timolol 0.5% instilled 12 hourly
5. Apraclonidine/latanoprost
6. Definitive Rx  surgical/laser iridotomy

23. Thankyou