Glaucoma Drugs

Question 1

What produces aqueous humor?

Answer 1

the ciliary body

Question 2

Main outflow pathway for aqueous humor

Answer 2

trabecular matrix via schlemm canal

Question 3

Secondary pathway for aqueous humor

Answer 3

uveoscleral outflow

Question 4

Glaucoma definition

Answer 4

hypertension of the eye (IOP) resulting in damage to the optic nerve = vision loss

Question 5

Ocular Hypertension

Answer 5

increased intraocular pressure without damage to the optic nerve = NO vision loss

Question 6

Increased intraocular pressure results from: (2)

Answer 6

a. decreased outflow pathways (blockage)
b. increased aqueous humor production

Question 7

Primary Open-Angle Glaucoma (POAG)

Answer 7

angle between iris and cornea is open
—> results from increased resistance to outflow through the trabecular meshwork (cannot exit through canal of Schlemm

Symptoms: none until too late

Question 8

Acute Angle-Closure Glaucoma

Answer 8

angle between iris and cornea is closed
–> results from a physical obstruction of outflow pathway by the iris

Symptoms: unilateral, red eye, hazy cornea, dilated pupil, dull pain
–> dilated pupil is what causes the blockage

Question 9

Drug therapy for glaucoma

Answer 9

goal is to reduce elevated IOP to minimize nerve damage and prevent vision loss

Question 10

How does drug therapy for glaucoma decrease OP? (2)

Answer 10

a. improving aqueous humor outflow
b. reducing aqueous humor production

Question 11

1st line monotherapy drugs

Answer 11

Prostaglandin F2 Alpha Analogs (“immitators”)

Question 12

2nd line or adjunctive therapy

Answer 12

a. beta adrenergic antagonists (beta blockers)
b. alpha 2 adrenergic antagonists
c. carbonic anhydrase inhibitors
d. parasympathetic agents (cholinergic agonists)

Question 13

Prostaglandin F2 Alpha Analogs

Answer 13

Lantanoprost, Travoprost, Bimatoprost
–> lowers IOP in glaucoma or ocular hypertension by facilitating aqueous humor outflow (mostly uveoscleral outflow)

effects: can cause darkening of pigmentation of the iris and eyelid, thickening/ lengthening of eyelashes

Question 14

Beta Adrenergic Antagonists (blockers)

Answer 14

Timolol, Levobunolol, Betaxolol
–> lowers IOP by decreasing production of aqueous humor in the ciliary boddy mostly through beta-2 receptor antagonism

Question 15

Alpha 2 Adrenergic Agonists

Answer 15

Brimonidine, Apraclonidine
–> lowers IOP by reducing ocular vasoconstriction, reducing aqueous humor production in the ciliary body (may improve aqueous humor outflow)

Adverse effects; SLUDGE+

Question 16

Carbonic Anhydrase Inhibitors

Answer 16

Brinzolamide, Dorzolamide
–> inhibit the enzyme carbonic anhydrase that facilitates the reaction involved in aqueous humor production
reduce IOP by decreasing production of aqueous humor in the ciliary body

Adverse Effects: ocular stinging, bitter taste, allergic reaction in 10-15% of patients

Question 17

Cholinergic Agonists

Answer 17

–> cause contraction of the
ciliary muscle which improves
trabecular outflow but focuses
the lens for near vision
(accommodation) –> good for
closed angle
–> also cause constriction of
pupil (miosis) that pulls the iris
away from the pores of the
trabecular meshwork

Use: emergency treatment of acute angle-closure glaucoma

Adverse effects: SLUDGE+, possible cataracts with long term use