pharmacotherapy in glaucoma
Post on 11-Jan-2017
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Pharmacotherapy of glaucoma
Dr. Samten Dorji
Outline
• Introduction• Pharmacotherapy• Classification and mechanism of action• Summary
Introduction
• Glaucoma is a group of ocular disorders with multifacorial aetiology united by a clinically characterstic intraocular pressure-associated optic neuropathy.
Pharmacotherapy
• Prevention or modification of risk factor
Intraocular pressure
Classification
Topical drugs• Cholinergic agents• Adrenergic agonists• Beta blockers• Prostaglandin analogs• Carbonic anhydrase
inhibitors
Systemic drugs• Carbonic anhydrase
inhibitors• Osmotic agents
Mechanism of action
• Decrease aqueous production in the ciliary body
• Increase aqueous humor outflow through the trabecular meshwork and uveoscleral pathway
Cholinergic drugs
Direct acting miotic
Cholinesterase inhibitors
Pilocarpine (direct acting)
• Relieves the pupillary block in angle closure glaucoma
• Increases the trabecular outflow • 0.5-0.4%• Last for 4-8 hours• superficial punctate keratitis, ciliary muscle spasm
which can lead to browache, induced myopia, miosis, possible retinal detachments, progression of cataract and corneal endothelial toxicity
Cholinesterase inhibitors
• Short acting-Physostigmine, neostigmine and demecarium
• Long acting- ecothiophate and isofluorophate• angle closure and open angle glaucoma• profound muscle weakness and cystoid
macular edema
Adrenergic agonist
• Decreases aqueous humor production and increases trabecular outflow
• May last upto 72 hours• Conjunctival decongestion and transient
mydriasis. Systemic hypertension, stinging, browache, conjunctival hyperemia, adenochrome deposits and allergic lid reactions
Adrenaline
Brimonidine
• First line agent• Highly selective alpha 2 receptor agonist• 0.2%• suppressing the rate of aqueous humor flow
and enhancing uveoscleral flow
Beta adrenergic antagonist(timolol)
• Inhibits both beta 1 and beta 2 adrenergic activity• First line agent• 0.25% or 0.5%• Duration of action exceeds 7 hours• localized irritation of the corneal epithelium can
result in blurred vision, conjunctival hyperemia, superficial punctate keratopathy and dry eye symptoms
• Short term escape and long term drift
Prostaglandin analogues
• Mediated by prostanoid receptors• Enhancing uveoscleral outflow• 0.005% and instilled at night• Duration of action 24 hours• Mild conjunctival hyperemia, punctate
corneal erosions and lengthening and thickening of eyelashes
Latanaprost
Carbonic anhydrase inhibitors
• It reversibly blocks the enzyme carbonic anhydrase in the ciliary body and thus suppresses aqueous humor production
• 125-250mg four times daily• Gastrointestinal upset, myopia, pulmonary
failure, renal stones, aplastic anaemia, metabolic acidosis, hypersensitivity reactions and peripheral neuropathy
Acetazolamide
Dorzolamide
• Topical ophthalmic use• It penetrates cornea, inhibits carbonic
anhydrase-II in the ciliary body, slows the production of local bicarbonates and thus decreases sodium and fluid transport which in turn reduces the secretion of aqueous humor
• 2% twice daily• irreversible corneal edema in patients having a
compromised endothelium
Osmotic agents
• Enhance the osmotic pressure of plasma• Mannitol, glycerol and urea• Acute angle closure glaucoma and pre
operative raised IOP• nausea, vomiting, diuresis, headache,
diarrhea, chills and fever
Summary
Thank you
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