Transcript ANTIGLAUCOMA MEDICATION

ANTIGLAUCOMA MEDICATION
DR.SHEERA ARUN
CARBONIC ANHYDRASE INHIBITORS
• Only drug systemically administered.
• Belong to sulfonamide class
• Acetazolamide is the prototype
MOA
• CO2 + H2O = H2CO3 = HCO3- + H+
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CA
• CA Isoforms-CA1 –CA14
• In the eye-CA1-CA IV
• Cytosolic CA II isoform (type c) in the ciliary
process is the main therapeutic target.
MECHANISMS
• 1.Alteration of ion transport associated with
aqueous humor secretion.
• Net chloride flux across the ciliary epithelium
is inhibited by creation of local acidic
environment.
• 2.Metabolic acidosis- also reduce the IOP.
• 3.Acetazolamide increases the blood flow
within the middle cerebral artery
• IV Acetazolamide increase choroidal blood
flow.
• Metabolic acidosis improves visual function by
increasing optic nerve blood flow.
• 4.Adrenergic effect of CAIs has been studied
• 5.Diuretic effect is not a factor in the
reduction of IOP.
• 6.CAIs in the retina result fluid movement
from retina to choroid = increase SRF
absorption in RD. Also useful in treatment of
macular edema RPE disease, c/c iridocyclitis,
CA Inhibition
• Oral : 21%-30%
• Topical : 17%-18%
• Acetazolamide slows nocturnal flow rate by
24%
• CAI+ Timolol: 44%
• Acetazolamide increases aq. Protein
concentration
ADMINISTRATION
• Acetazolamide: 95%protein bound: minimal
metabolism: 100% renal excretion:dose
125,250mg 6 hrly.
• Methazolamide: 55%protein bound: 75%
metabolism: 25% renal excretion: 25,50mg
twice daily
• In children: 5-10mg/kg every 4-6 hrly
• In Tab- hypotensive effect peaks in 2hrs-last
up to 6hrs
• In Cap- peak in 8hrs- persist beyond 12hs
• IV- peak effect 15mts- duration of 4hrs
METHAZOLAMIDE
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Smaller dose needed
Fewer s/e
Long plasma ½ life
Low rate of protein binding
More active on a weight basis
Fewer renal s/e(renal stone has been
reported)
SIDE EFFECTS
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OCULAR:idiosyncratic transient myopia
Ciliary body edeme
Choroidal detachment
SYSTEMIC:paresthesia
Urinary frequency
Serum electrolyte imbalance
Metabolic acidosis
• Malaise, fatigue, wt loss, anorexia,
depression, decreased libido
• Potassium depletion
• GI symptoms
• Blood dyscrasias
• Other sulfonamide related s/e; maculopapular
rash, urticaria,SJS,increased blood uric acid,
hirsuitism, transient increase of CSF pressure
• Teratogenic effect in animals,so caution in
pregnancy
TOPICAL
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DORZOLAMIDE;
CA II isoenzyme blocked
0.5%, 1%, 2% used
3 times daily dosage
BRINZOLAMIDE
1% sln 2 times daily
SIDE EFFECTS
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Irritation
Bitter taste
Transient blurred vision
Periorbital dematitis
Corneal edema
Systemic: abnormal taste;thrombocytopenia
CHOLINERGICS
• Parasympathomimetics
• Cholinergic agonists
• Miotics
PILOCARPINE
• MOA• Other effects-
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ADMINISTRATIONPenetration
Concentration
Frequency
Delivery systems
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Delivery systems
Drops
Gel
Membrane controlled delivery system
Other vehicles
Subconjunctival injection
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DRUG INTERACTIONSMiotics
Adrenergic agonists
Adrenergic antagonists
Prostaglandin agonists
CAIs
Antibiotics and corticosteroid ointments
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SIDE EFFECTS
Systemic
Diaphoresis
Contraction of smooth muscle
Stimulation of glands
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OCULAR
Ciliary muscle spasm
Indused myopia
Miosis
Retinal detachment
Catractogenic effect
Corneal endothelial toxicity
• Blood aqueous barrier permeability to
protiens
• Cicatritial pemphigoid
• Hypersencitivity and toxic reaction
• Atypical band keratopathy
CARBACHOL
• DUAL ACTION
• DOSE
• ADVERSE EFFECTS
ECHOTHIOPHATE IODIDE
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MOA
DOSE
ADVANTAGE
SIDE EFFECTS
HYPEROSMOTICS
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SYSTEMICALLY
MOA
GLYCEROL
MANNITOL
SIDE EFFECTS
INDICATION