Ocular Pharmacology Flashcards
What modifications can be made to steroids to make them more hydrophobic or hydrophilic?
Alcohol or acetate- hydrophobic
Phosphate- hydrophilic
Why is inflammation sometimes useful for drug penetration to the cornea?
Reduces the hydrophobic nature of the endothelium
What is benzalkonium?
Preservative which can be added to drugs to enhance their corneal penetration
How can topical ocular drugs gain systemic absorption?
In the nasopharynx (via the nasolacrimal duct)
What is the mechanism of action of chloramphenicol?
Inhibits bacterial peptidyl transferase
What are the possible side effects of chloramphenicol?
Allergy
Aplastic anaemia (very rare)
Grey baby syndrome (accumulation of toxic metabolites)
What is the mechanism of action of aciclovir and when is it used?
Base analogue. Dendritic corneal ulcers, in conjunction with systemic treatment for opthalmic zoster
When are topical steroids used?
Post-op for cataracts To prevent corneal graft rejection Uveitis Allergy General inflammation
In what sight-threating situation might systemic steroids be used?
Temporal arteritis
In what situation should a topical steroid not be used?
Unconfirmed case of red eye- may be herpetic, and this would exacerbate the infection and may cause corneal ulceration/melt
What are possible local side effects of steroids?
Cataract, glaucoma
When would the following drugs be used:
a) topical “mast cell stabilisers”/antihistamines
b) topical NSAIDS
a) allergic conjunctivitis
b) Post-surgery/laser treatment
Which classes of drug are used in the treatment of glaucoma?
Prostaglandin analogues e.g. latanoprost (increase uveoscleral outflow)
Beta blockers e.g. timolol (reduce rate of aqueous humour production)
Carbonic anhydrase inhibitors e.g. dorzolamide (reduce humour production. Systemically- diuresis)
Miotics e.g. pilocarpine
B2 adrenoceptor agonist e.g. brimonodine
Which drugs can be delivered intra-vitreally?
Anti-VEGF
Antibiotics in endopthalmitis
Steroids
Which drops can be used as
a) mydratics
b) diagnostic dye
c) local anaesthetic
a) phenylephrine, atropine, mydrilate, tropicamide
b) fluouroscein
c) lidocaine, tetrocaine
