ocular pharmacology Flashcards
The amount of time the drug stays on the eye can be extended with
gel, ointment or solid insert formulations.
Extent of absorption depends on:
- Time drugs remains in cul-de-sac of eye
- Degree of elimination by naso-lacrimal drainage
- Drug binding to proteins in tears
- Drug metabolism by enzymes in tears and ocular tissues
- Rate of diffusion across cornea and conjunctiva
- Degree of passive diffusion through cornea into aqueous humor (greatest with drugs that have both lipophilic and hydrophilic properties)
Closed-angle glaucoma:
- results in intermittent rapid fluctuations in IOP due to mechanical blockage of the trabecular system.
- The goals of treatment for closed-angle glaucoma are to reduce pressure rapidly at the time of an attack until surgery can be performed.
Drugs that increase flow of aqueous humor rapidly:
pilocarpine
Drugs that reduce aqueous humor production rapidly:
acetazolamide
Drugs that dehydrate the eye to rapidly reduce IOP:
mannitol or glycerol
Glaucoma refers to:
disorders of the eye that result in damage to the optic nerve.
This damage to optic nerve in glaucoma is often due to:
increased intraocular pressure (IOP) due to defects in the pathway for drainage of aqueous humor.
Lowering IOP has been shown to significantly reduce progression in glaucoma.
Drugs that reduce aqueous humor production:
- Beta-adrenergic agonists
2. Carbonic anhydrase inhibitors
Drugs that increase flow of aqueous humor:
- Prostaglandin analogs
- Alpha-adrenergic agonists
- Cholinergic agonists
- Echothiophate
The goals of treatment for the most common form of glaucoma, open-angle glaucoma, are:
- to reduce aqueous humor production
2. enhance aqueous humor outflow.
Normal pathway of aqueous humor in the eye:
aqueous humor is produced by the ciliary processes in the posterior eye –> flow through pupil into anterior eye –> trabecular meshwork drains the fluid via Schlemm’s canal into the bloodstream