glaucoma pharmacology Flashcards
what is aqueous humor
Supplies nutrients to and removes waste from the lens and cornea (avascular) - rate of production normally equals outflow
what are the two pathways for aqueous humor to leave the eye
conventional - canal of schlemm to episcleral vessels
uveoscleral - ciliary muscles, choroid and sclera
what facilitates the conventional pathway of aqueous humor removal
facilitated by pupil contraction via M3 ACh (parasympathetic)
inhibited by pupil dilation NA alpha1 (sympathetic)
how is aqueous humor produced
ciliary epithelium
Na/K ATPase (sodium out of blood, potassium in), carbonic anhydrase produces HCO3
- controlled by B2 receptors (NA - sympathetic )
- stimulation of A2 receptors decreases AH production
inhibition of carbonic anhydrase reduces AH output
what are the 5 options for treatment of high IOP
beta blockers
alpha 2 agonists
carbonic anhydrase inhibitors
muscarinic antagonists
prostaglandin analogues
how do beta-blockers treat increased IOP
reduce AH secretion - timolol non selective
what are the s/e of beta blockers used for IOP
stinging
dry eye
itchy
erythema
bradycardia
breathlessness
C/I - bradycardia and heart block
how do alpha 2 agonists treat increased IOP
reduce AH secretion - brimonidine
how do carbonic anhydrase inhibitors treat increased IOP
reduce AH secretion - dorzolamide/brinzolamide
how do muscarinic antagonists treat increased IOP
increase AH drainage - M3 stimulation, ciliary contraction and pupil constriction - more drainage
what are the side effects of muscarinic antagonists to treat IOP
blurred vision
antimuscarinic systemic effects
how do prostaglandin analogues treat increased IOP
increased AH drainage
- latanoprost, travoprost and bimatoprost
- analogues of PGF2a and act at PGF receptors
what are the side effects of using prostaglandin analogues for IOP
bloodshot eyes
feeling of foreign body
ocular irritation
eyelash growing
iris hyperpigmentation
