Opthalmology pharmacology Flashcards
(56 cards)
What are the two requirements for topical ocular drugs?
Ability to act on the surface of the eye
Ability to penetrate the cornea
The epithelium of the cornea is hydrophilic and the stroma of the cornea is hydrophobic. T/F
False:
Epithelium = hydrophobic/lipid loving
Stroma = lipophobic/water loving
Which type of drugs penetrate the corneal epithelium and stroma respectively?
Epithelium - lipid soluble
Stroma - water soluble
Which ocular antibiotic possesses both lipophilic and hydrophilic qualities?
Chloramphenicol
What can alter the properties of the epithelium and in what way?
Inflammation can cause the epithelium to become more hydrophilic
What can alter the properties of the stroma and in what way?
The tear film can cause the epithelium to become more hydrophobic
How can topical steroids be altered to make them more 1) hydrophobic and 2) hydrophilic?
1 - alcohol/acetate
2- phosphate
When does prednisolone acetate penetrate the cornea best?
When it is uninflamed
When is prednisolone acetate used?
Post-operatively
When does prednisolone phosphate penetrate the cornea best?
When it is inflamed
When is prednisolone phosphate used?
In corneal disease or when low dose steroids are required
What chemical can alter the properties of the tear film? What else is it useful for?
Benzalkonium (makes it less hydrophobic). Also a preservative
Where can excess topical ocular drugs get systemically absorbed? How can this be halted?
Nasopharynx (via nasolacrimal duct). Punctal occlusion for five minutes
Other than topical, what are some routes of administration?
Subconjunctival, subtenons, intravetral, intracameral
Name some frequently used ocular antibiotics
Chloramphenicol, gentamicin, ofloxacin
Name an ocular antiviral
Zovirax
What are the types of anti-inflammatory agents used in the eyes?
Steroids, topical NSAIDs, anti-histamines and mast cell stabilisers
When are steroids used?
Post-op cataract surgery
Uveitis
Prevention of corneal graft rejection
What steroid is typically used in uveitis?
Prednisolone acetate
What are the local effects of steroids?
Cataract, glaucoma and exacerbation of viral infection
What are the systemic effects of steroids?
Osteoporosis, weight gain, gastric ulcers, immunosuppression
How is temporal arteritis treated?
Oral steroids
List the strengths of topical steroids from weakest to strongest
Fluorometholone (FML) >
Predsol (prednisolone phosphate) >
betamathasone >
dexamethasone/prednisolone acetate
When are anti histamines or mast cell stabilisers used?
Hayfever, allergic conjunctivitis
