Pharmacology Flashcards
Epithelium is ….. therefore …. soluble drugs penetrate the epithelium
epithelium is lipophilic/hydrophobic therefore lipid soluble drugs penetrate the epithelia
Stroma is …. therefore …. soluble drugs penetrate the stroma
stroma is lipophobic/hydrophilic therefore water soluble drugs penetrate stroma
Chloramphenicol is both …. & …..
lipophilic and hydrophilic
ocular surface inflammation can …. the hydrophobic nature of the epithelium and ….. penetration
ocular surface inflammation can reduce the hydrophobic nature of the epithelium and increase penetration
Dry eyes … penetration?
Aid
Hydrophilic drugs are limited by the …
epithelium
Hydrophobic drugs are limited by the ….
stroma
Adding ……. or …… to a steroid makes it more ….. and allows penetration of the ……
Adding alcohol or acetate to a steroid makes it more hydrophobic and allows penetration of the epithelium
Adding ……. to a steroid makes it more ….. and allows penetration of the ……
Adding phosphate to a steroid makes it more hydrophyllic and allows penetration of the stroma
Describe prednisolone acetate
Hydrophobic
Good penetration of cornea
Used post-op
Describe prednisolone phosphate
Hydrophilic
Poor penetration of un-inflamed cornea
Used for cornea disease or for low dose steroid
What is belzalkonium chloride?
Used as surfactant
Antibacterial agent
Aids penetration of hydrophilic drugs
What does benzalkonium cause?
Dry eye, disruption of tear film
What is bimatoprost?
IOP lowering drug containing benzalkonium
How can systemic absorption of topical drugs be reduced?
-punctual occlusion
pinch tear duct for 5 minutes and then close eye; useful when using drugs like B blockers
Describe subtenons drug administration
fibrous layer which starts at limbus and regresses with age
drugs enter back of orbit
What can’t be used in intravitreal injections?
Toxic drugs
When is intravitreal injection used?
Endophthalmitis
What is the benefit of intracameral injection?
Can use high dose steroids without systemic effect
What drugs are used to treat infection?
Chloramphenicol Aciclovir (zovirax) Flucloxacillin (Exocin) Dexathametasone (maxidex) Prednisolone
When are steroids used topically?
- post-op cataracts
- uveitis
- to prevent corneal graft rejection
- temporal arteritis
When are topical NSAIDs used?
pain relief eg post refractive laser
given in patients with macular oedema
corneal abrasion
What are anti-histamines used for?
Hay fever
What are mast cell stabilisers used for?
Uncontrolled allergic eye disease
How does pilocarpine work?
parasympathomimetic, open up drain
glaucoma
How does acetazolamide work?
carbonic anhydrase inhibitors, reduce aqueous production
glaucoma
How does xalatan (lantanoprost) work?
Open drain
glaucoma
How does timolol work?
b blocker; turn off tap by blocking b receptors in ciliary body
What are the local side effects of steroids?
cataract
glaucoma
exacerbation of viral infection
What are fluorescein drops used for?
- shows corneal abrasion
- shows dendritic ulcer
- identified leaks
- tonometry
- diagnosing nasolacrimal duct obstruction
- angiography
Name some dilating drops?
- atropine
- phenylephrine
- hydrochloride
- tropicamide
- mydrilate
Which dilating drops block parasympathetic?
tropicamide, cyclopentolate
How do sympathomimetic drugs work?
causes pupil to dilate (dilator pupillae)
How do local aesthetics work?
Block sodium channel and impede nerve conduction
When are local anaesthetic drops used?
- FB removal
- tonometry (IOP measurement)
- corneal scraping
- comfort
- cataract surgery
What shouldn’t be given in herpetic keratitis
steroids
What does vigabatrin cause?
Anticonvilsant which causes irreversible contraction of visual field
What can ethambutol cause?
Optic neuropathy
What does hydroxychloroquine at high doses cause?
Maculopathy
What does amiodarone cause?
Vortex keratopathy (brown pigmentation of epithelium of cornea)
