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Medicines Used for Glaucoma Management _Optom Lecture
The document outlines various treatments for glaucoma, emphasizing the need to reduce aqueous humor production or promote its drainage to manage intraocular pressure (IOP) effectively. It categorizes anti-glaucoma medications based on their mechanisms, detailing specific drugs within each category, their dosages, side effects, and contraindications. Additionally, it highlights the rationale for combination therapy, suggesting the use of complementary medications to optimize treatment outcomes.
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Medicines Used for Glaucoma Management _Optom Lecture
- 1. Medicines used for Glaucomamanagement Dr Gauri Sr Shrestha, IOM, TU
- 2. Principle summary ofglaucoma treatment 1. Reduce secretion of aqueous humour • Cells responsible for Aqueous secretion: non- pigmented epithelium of the ciliary body
- 3. Principle summary ofglaucoma treatment 2. Promote aqueous humour drainage • Trabecular meshwork (90%) • Uveoscleral flow (10%)
- 4. Goals and plansof glaucoma treatment • Goals • Lower IOP at a level that will stop or slow the progression of optic nerve damage and related loss of visual functions • The purpose of the therapy is not glaucoma cure but rather is its control • Plans • Choose a drug with the lowest concentration • Use drugs with potentially fewer side effects • If IOP does not fall significantly with monotherapy, select a combination therapy.
- 5. Categories of anti-glaucomamedicines Increase aqueous outflow (primary) 1. Cholinergic drugs (e.g., pilocarpine, carbachol) 2. Cholinesterase inhibitor (e.g., physostigmine, echothiophate) 3. Prostaglandin analogue (e.g latanoprost,Bimatop rost unoprostone, travoprost) Decrease production of aqueous humour (primary) 1. Non-selective β-adrenergic blocker (e.g., timolol, levobunolol, metipranolol, carteolol) 2. Selective β-blocker (e.g., Betaxolol) 3. Non-selective α-adrenergic agonist (e.g., epinephrine, dipivefrin) 4. Selective α2-adrenergic agonist (e.g., clonidine, apraclonidine, brimonidine) 5. Carbonic anhydrase inhibitor (e.g., dorzolamide, brinzolaminde, acetazolaminde, methazolamide) 6. Hyperosmotic agents (e.g., oral glyceride, IV mannitol, Urea)
- 6. Increase aqueous outflow(primary action) 1. Cholinergic drugs (e.g., pilocarpine, carbachol) 2. Cholinesterase inhibitor (e.g., physostigmine, echothiophate) 3. Prostaglandin analogue (e.g latanoprost, unoprostone, travoprost)
- 7. 1. Cholinergic medicine(Pilocarpine 1%, 4%) • Enhance aqueous outflow by contraction of the ciliary muscle in OAG (not commonly used due to inherent side effects of cholinergic drugs) • Release pupillary block (therapeutic management of ACG) • Dose: TID – QID (increase dose in darkly pigmented eyes) • Side effects • Systemic: perspiration, stimulation of glands, contraction of smooth muscles, pulmonary oedema. • Ocular: ciliary muscle spasm, retinal detachment, vitreous haemorrhage, corneal endothelial toxicity, cataract, band keratopathy, cicatricle pemphigoid, hypersensitivity, and toxic reaction. • Contraindication: age below 40 years (accommodative spasm), uveitis, and neovascular glaucoma ACG = angle closure glaucoma, OAG = open-angle glaucoma
- 8. 2. Cholinergic medicine(Carbachol 0.75 – 3%) • A synthetic analogue of acetylcholine • Poorly absorb across the cornea • Alternative: pilocarpine (fails to control IOP) • Dose: TID • Side effects: ocular pain, impaired vision, pseudomyopia
- 9. 3. Prostaglandin (PG)analogue • Mediators of inflammation (a product of cell membrane PLs by the action of COX-related enzyme) • PG receptors: • ciliary muscles, iris sphincter, trabecular meshwork • Reduce IOP by 1. Increase uveal-scleral outflow by relaxing ciliary muscles 2. Increase aqueous outflow through the trabecular meshwork • Reduce IOP by 25%
- 10. 3. Prostaglandin (PG)analogue • Side effects: • burning, blurred vision, itching, FB sensation, conjunctival hyperemia, increase coronary blood flow, bronchoconstriction, CME in aphakia and pseudophakia, increase iris pigmentation, hypertrichosis of eyelashes, anterior uveitis • Latanoprost 0.005% (Xalatan): • acts on PG receptor 1 (predominant) • Bimatoprost 0.01%, 0.03% (Lumigan): • mimics PG-α2 receptor without acting on any PG receptor (both 1 and 2) • Travoprost 0.004% (travatan) • similar to latanoprost, stable at room temperature
- 11. Decrease production ofaqueous humour (primary action) 1. Non-selective β-adrenergic blocker (e.g., timolol, levobunolol, metipranolol, carteolol) 2. Selective β-blocker (e.g., Betaxolol) 3. Non-selective α-adrenergic agonist (e.g., epinephrine, dipivefrin) 4. Selective α2-adrenergic agonist (e.g., clonidine, apraclonidine, brimonidine) 5. Carbonic anhydrase inhibitor (e.g., dorzolamide, brinzolaminde, acetazolaminde, methazolamide) 6. Hyperosmotic agents (e.g., oral glyceride, IV mannitol, Urea)
- 12. 1. Adrenergic receptors: β-blockers • Reduce aqueous secretion by blocking beta- receptors (reduce Cl- ions) • Receptors: • β1: heart and kidney • β2: bronchi (asthmatic patients)
- 13. 1. Side effectand Contraindication of β- blocker • Side effects of β-blockers • Bradycardia, systemic hypotension, bronchospasm, amnesia, nausea • Alopecia, hypoglycemia, dry eye, loss of corneal sensation, uveitis, cataract • Contraindications • Asthama, COPD, Bradycardia, heart block, children, pregnancy
- 14. 1. Non-selective β-blockers Timolol0.25, 0.50 • A well-tolerated ophthalmic solution • Dose: BD • Efficacy decline with long-term use • Side effect: cardiovascular and respiratory complications Levobunolol (betagon 0.5) • Similar to timolol Metipranolol 0.1, 0.3 • Similar to levobunolol • Gives more stinging sensation than levobunolol Carteolol 1.0, 2.0 • Less potent than other drugs in this group Commonly used or available medicines
- 15. 2. Selective β-blocker Betaxolol0.25, 0.50 • Less bronchoconstriction than timolol because of its cardioselectivity (effective more on β1 receptor than β2 receptor. • Modest reduction in IOP. • More effective in slowing the rate of VF deterioration. Commonly used or available medicines
- 16. 3. Adrenergic receptors •Decrease IOP in POAG, increase IOP in ACG • Causes pupil dilation • Acts on two types • α1-receptors • arterioles, dilator pupillae, and muller muscle • Its stimulation causes hypotension, mydriasis, and lid retraction • α2-receptors • are located in the ciliary epithelium and presynaptic adrenergic nerve terminals. • Its stimulation inhibits the aqueous secretion
- 17. 3. Non-selective α-adrenergicagonist (e.g., epinephrine, dipivefrin) Dipivefrin 0.1% • Prodrug • Less effective than timolol • Side effects: reactive hyperemia, endothelial damage and follicular conjunctivitis
- 18. 4. Selective α2-adrenergicagonist Brimonidine 0.2% (alphagan) • Highly selective for α2-adrenergic receptors • 1000 times more effective than α1- adrenergic receptors • No mydriasis and vasoconstriction and little effect on the cardiovascular system • Decreases aqueous secretion and enhances uveoscleral outflow. • Safe in long-term treatment • Has neuroprotective properties Apraclonidine 0.5%, 1.0% (Iopidine) • Reduce blood pressure and heart rate by reducing sympathetic tone • Significantly decrease IOP in post- operative cataract cases • No conjunctival hyperemia and blanching • Perceived contraindication: a narrow filtration angle, cardiovascular problems, peripheral vasospastic conditions, Horner’s syndrome Commonly used or available medicines
- 19. 5. Carbonic anhydraseinhibitor • Enzyme carbonic anhydrase produces HCO3 - ions from CO2 and H2O. • The HCO3 - ions move to the posterior chamber along with Na+ through trans-epithelial movement of bicarbonate ions in the ciliary epithelium. • CAI competes with bicarbonate ions and block HCO3 - ion formation from CO2. • Dorzolamide 2.0%, Brinxolamide 1.0% • Dose: BD – TID • Effect similar to Betaxolol (a selective β blocker) • Adjunct therapy: B-blockers (dose BD) • Acetazolamide • Has poor ocular penetration, and is not effective topically • Oral dose: 250 – 500 mg BD Commonly used or available medicines
- 20. 5. Side effectsand contraindications of Carbonic anhydrase inhibitor Contraindications Hypersensitivity, impaired renal function, COPD, a patient using potassium-depleting drugs, neovascular glaucoma Side effects
- 21. 6. Hyperosmotic agents(e.g., Oral glyceride, IV Mannitol) • Vitreous shrinkage leads to an osmotic gradient b/w blood and ocular tissue which drain fluids from the eyes. • Side effects • Major: nausea, vomiting, diuresis • Others: headache, backache, giddiness, diarrhea, confusion, disorientation, cardiovascular overload, intra-cranial haemorrhage, pulmonary oedema, acidemia, and renal insufficiency • Glycerol • Dose: 1 – 1.5 mg/kg body weight (50% solution) • IV mannitol (20%) • Dose: 1 – 2 gm/kg body weight in 30 mins
- 22. Rationale for combinationtherapy • Do not use drugs of the same group • Select two drugs combination • The first-line treatment has no effect or more adverse effect, change this drug than using combination therapy. • No results with combination therapy, change drug than increasing doses.
- 23. Sample combination therapy (feelfree to update this table) Primary Additional Medicine examples (if available in combination) Alpha-1 agonist • β - blocker Beta blocker • α - agonist Combigan, Brimolol (Brimonidine Tartarate 0.2% W/V + Timolol Malate 0.5%W/V), • Cholinergic • Prostaglandin Xalacom (timolol 0.5% and Latanoprost 0005%), DuoTrav (Timolol 0.5% and Travoprost 0.004%), Ganfort (Timolol 0.5% and Bimatoprost 0.03%) • Topical CAIs Cosopt (dorzolamide 2%-timolol 0.5%) Cholinergic • Beta-blocker • Topical CAIs Prostaglandins • Beta-blocker • Topical CAIs Topical CAIs • Alpha 2 agonist Simbrinza (brinzolamide 1%-brimonidine 0.2%) • Beta-blocker • Prostaglandins
- 24. Choice of drug •Betaxolol (Selective β-blocker): NTG, COPD • Common combination therapy: • timolol (Non-selective β – blocker) + latanoprost (Prostaglandin analogue) • timilol (Non-selective β – blocker) + dorxolamide (Carbonic anhydrase inhibitor) • Pregnancy: Brimonidine (Selective α2-adrenergic agonist) NTG = norma tension glaucoma COPD = chronic obstructive pulmonary disease
- 25.
- 26. Efficacy of anti-glaucomamedicine • Efficacy of monotherapy versus combination-therapy • Efficacy, recommendation and dose of prostaglandin analogue (e.g latanoprost and/or travoprost) • Comparison of selective (e.g., betaxolol) and non-selective beta- blockers (e.g., timolol and/or levobunolol) • β-blockers (e.g., timolol and/or levobunolol/ betaxolol) versus prostaglandin analogues (e.g latanoprost and/or travoprost) • β-blockers (e.g., timolol and/or levobunolol/ betaxolol) versus α- adrenergic agonist (e.g., apraclonidine, brimonidine)
Editor's Notes
- #10 Reduces collagen levels in the ciliary muscles by the production of MMPs.
- #11 Reduces collagen levels in the ciliary muscles by the production of MMPs.
- #13 No effect on outflow resistance. Β-blockers with a reduced effect on β2-receptors will have less effect on bronchi A usual BD therapy
- #17 Dose: BD Side effects: red eye, deposits on the cornea,
- #21 (numbness, tingling of extremities and peri-oral areas) dermatitis
- #22 Urea