Opthalmology pharmacology Flashcards
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
When might topical NSAIDs be used?
For pain e.g post laser surgery
What is glaucoma?
A group of diseases which bring about progressive and irreversible optic neuropathy (often with raised IOP) resulting in visual field defects
What is the only modifiable risk factor for glaucoma?
Raised IOP
How does glaucoma typically present?
Asymptomatic
Who screens for glaucoma?
Optometrists
What is the relationship between glaucoma and age?
Glaucoma increases with age
What are the categories of glaucoma medication?
Prostanoids Beta blockers Carbonic anhydrase inhibitors Alpha2 adrenergic agonist Parasympathomimetric Combination
Name a prostanoid medication
Latanoprost
Name beta blockers used in glaucoma
Timolol, betaxolol, levobunolol, carteolol
Name a topic and systemic carbonic anhydrase inhibitor
Topical - dorzolamide
Systemic - acetazolamide
Name an alpha2 adrenergic agonist
brimonidine
Name a parasympathomimetric
pilocarpine
Name a combination medication for glaucoma
dorzolamide and timolol (cosopt)
What are the side effects of alpha2 agonists?
Red eye
What is the main side effect of parasympathomimetric?
Night blindness
Name three scenarios in which intra-vitreal injections are used
Antibiotic delivery in endopthalmitis
Intra-ocular steroids
Anti-VEGF in wet macular degeneration
How does local anaesthetic work in the eye?
Blockage of sodium channels responsible for nerve conduction
List scenarios when local anaesthetic would be used
Foreign body removal
Tonometry
Corneal scraping
Comfort
What is a side effect of local anaesthetic?
Limited healing
List scenarios where diagnostic dye would be used
Detecting corneal abrasions
Tonometry
Detecting nasolacrimal duct obstruction
Angiography
What do mydriatic drugs do?
Dilate the pupil
How do mydriatic drugs work?
Block parasympathetic supply to the iris
What are the side effects of mydriatic drugs?
Vision blurring
AACG (acute angle closure glaucoma)
What do sympanometrics do?
Dilate the pupil
How do sympanometric drugs work?
Act on the sympathetic nerves suppling the iris causing them to dilate
Do sympanometric drugs affect the accomodation reflex?
No
Name some sympanometric drugs
Phenylephrine, atropine
Name some mydriatic drugs
Tropicamide, cyclopentolate
What is a side effect of the epilepsy medicine vigabatrin?
Constricted visual fields
What is a side effect of the TB drub ethambutol?
Optic nerve neuropathy
What is a side effect of the antimalarial/DMARD drug hydroxychloroquine?
Bullseye maculopathy when used long term
What is a side effect of amiodarone?
Corneal verticillata
