Pharmacology Flashcards
List the main routes of administration of ocular drugs
Topical (drops, ointments)
Subconjunctival
Subtenons
Ocular injection (intravitreal, intracameral)
Which type of drug - hydrophilic or lipophilic - can penetrate the ocular epithelium?
Lipophilic (lipid soluble drugs), since epithelium is hydrophobic and lipophilic
Which type of drug - hydrophilic or lipophilic - can penetrate the ocular stroma?
Hydrophilic (water soluble drugs), since stroma is hydrophilic and lipophobic
Chloramphenicol is both hydrophilic and lipophilic. True/False?
True
Penetrates cornea easily
What effect does ocular surface inflammation have on the hydrophobic nature of the ocular epithelium?
Reduces hydrophobic nature
Tear film may impede drug penetration. Why?
Lipid layer will impede hydrophilic agents
Hydrophilic drugs are limited by epithelium/stroma and lipophilic drugs are limited by epithelium/stroma
Hydrophilic drugs are limited by epithelium and lipophilic drugs are limited by stroma
How can topical steroid be made more hydrophobic (what can be added)?
Alcohol (acetate)
How can topical steroid be made more hydrophilic (what can be added)?
Phosphate
Prednisolone acetate is hydrophilic. True/False?
False
Hydrophobic (contains acetate)
Prednisolone phosphate has good penetration. True/False?
False
It is hydrophilic and thus doesn’t penetrate ocular epithelium well (epithelium is hydrophobic)
What can be added to a topical drug to increase corneal penetration?
Benzalkonium
Give an example of a drug that can be administered through the subconjunctival route
Steroid
Give an example of a drug that can be administered through the subtenons route
Local anaesthetic (via cannula)
List some anti-inflammatory agents for ocular disease
Steroid
NSAIDs
Anti-histamines
Mast cell stabilisers
When are topical steroids usually used for ocular disease?
Post-op cataracts
Uveitis
Prevent corneal graft rejection
List some local ocular side effects of steroids
Acute glaucoma
Cataract
Exacerbation of viral infection
How do glaucoma drops basically work?
Decrease production of fluid and/or increase fluid outflow/drainage from the eye through the trabecular meshwork
Which class of drug is 1st line for glaucoma and how does it work?
Prostanoids - Latanoprost (Xalatan)
Opens up uveal-scleral outflow (makes vessels leakier to allow fluid drainage)
How to beta-blockers and carbonic anhydrase inhibitors help in glaucoma?
Block ciliary body and thus decrease fluid production
‘Turn off vitreous tap’
Give an example of a carbonic anhydrase inhibitor
Topical Dorzolamide
Systemic Acetazolamide
How do alpha agonists help in glaucoma? Give an example of one
Brimonidine
Make all vessels leakier and thus increase fluid drainage
How do parasympathomimetics help in glaucoma? Give an example of one
Pilocarpine
Pull iris tight together to open up trabecular meshwork and enable fluid drainage
‘Turn off vitreous tap and unblock drain’
Name a pro + con of intravitreal drug administration
Deliver effective concn of drug
Can be toxic to retina
When is intravitreal drug administration mainly used?
Administering antibiotic in exophthalmitis
Intra-ocular steroids
What effect does local anaesthetic have on the eye?
Blocks sodium channels + impedes nerve conduction so can keep eye open
Which dye is useful for viewing corneal abrasions?
Fluorescein dye
What do mydriatics do? Give an example and side effect
Block parasympathetic supply to iris, causing pupil dilation
Tropicamide
Side effect: blurring, acute glaucoma
List weak and strong steroids used in the eye
WEAK: FML, predsol
STRONG: betamethasone, dexamethasone, prednisolone
What do sympathomimetics do? Give an example
Cause pupil to dilate by increasing sympathetic supply
Phenylephrine, atropine
