Ocular pharmacology

Question 1

Greater drug absorption into the eye

Answer 1

Prolonged time in cul-de-sac and precorneal tear film, slow nasolacrimal drainage, binding to tear proteins, tissue esterase transformation, easy diffusion across cornea and conjunctiva

Question 2

Path of aqueous humor production and drainage

Answer 2

secreted by ciliary body epithelium –> travels around outer margin of iris –> drains into the canal of Schlemm

Question 3

What is normal IOP?

Answer 3

10-15mm Hg above atmospheric

Question 4

What IOP is associated with glaucoma?

Answer 4

> 22 mm Hg

Question 5

Latanoprost

Answer 5

Prostaglandin analog. First line to increase aqueous humor outflow via accessory uveoscleral outflow pathway
Side effects: ocular irritation; few if any systemic

Question 6

Brimonidine

Answer 6

Alpha-adrenergic agonist. add-on second/third-line therapy for glaucoma.

MOA: increased uveoscleral outflow of AH; inhibits AH formation

Side effects: red eye and ocular irritation. CNS depression. Apnea in infants

Question 7

Timolol

Answer 7

Beta-adrenergic antagonist. Second-line for glaucoma.

MOA: blocks B-receptor pathway –> reduced AH production

Side effects: systemic beta-blocker effects

Question 8

Pilocarpine

Answer 8

Cholinergic agonist. Less commonly used.

MOA: muscarinic receptor –> contracted ciliary muscle –> AH outflow

Side effects: ciliary spasm –> headaches, myopia, dim vision

Question 9

Dorzolamide

Answer 9

carbonic anhyrase inhibitor. add-on second/third-line for glaucoma

MOA: inhibits CA on ciliary body epithelium –> reduced HCO3- –> reduced fluid transport and IOP

Side effects: Minimal with topical admin. Bitter taste

Question 10

Closed-angle glaucoma

Answer 10

extreme fluctuations in IOP

Question 11

Bacterial conjunctivitis/keratitis

Answer 11

Empiric: erythromycin ointment or Polytrim drops

Sulfa allergies? use azithromycin

More severe –> fluoroquinolones

Question 12

HSV keratitis

Answer 12

Oral acyclovir, topical trifluridine

Question 13

Viral conjunctivitis treatment

Answer 13

Self-limiting. Treat symptoms with OTC antihistamines, artificial tears

Question 14

Vasoconstrictors/antihistamines

Answer 14

used in allergic conjunctivits

Question 15

Glucocorticoids

Answer 15

ocular inflammatory diseases.

Dexamethason and prednisolone

Side effects: posterior subcapsular cataracts, secondary infections, secondary open angle glaucoma

Question 16

Topical NSAIDs

Answer 16

Miosis during cataract surgery –> Flurbiprofen
Seasonal allergy conjunctivitis –> ketorolac
Postop inflammation –> diclofenac