Pharmacology Flashcards
Corneal epithelium is:
Lipophilic/hydrophobic
What kind of drugs penetrate corneal epithelium?
Lipid soluble
Corneal stroma is:
Lipophobic/hydrophilic
What kind of drugs penetrate corneal stroma?
Water soluble
Drug that has lipophilic and hydrophilic properties
Chloramphenicol
What makes a steroid hydrophobic?
Alcohol
Acetate
= good penetration of uninflamed cornea
What makes a steroid hydrophilic?
Phosphate
= good penetration of inflamed cornea
Inflammation makes cornea:
more hydrophilic
How to enhance corneal penetration
Change drug (make hydrophobic/hydrophilic) Add preservative, disrupts lipid layer (benzalkonium)
Drug that inhibits bacterial protein synthesis
Chloramphenicol
Inhibits peptidyl transferase
Is chloramphenicol bacteriostatic or bactericidal?
Bactericidal for Strep and Haemophilus
Bacteriostatic for Staph
Side effects of chloramphenicol
Aplastic anaemis
Grey baby syndrome
Antibiotics that inhibit nucleic acid synthesis
Quinolones, e.g. Ofloxacin
Inhibits DNA gyrase = prevents supercoiling
What is ofloxacin used to treat?
Bacterial keratitis
Antibiotics that inhibit cell wall synthesis
Penicillins and Cephalosporins - B lactam ring (inhibits enzyme for cell wall)
When are steroids used?
Post-op cataracts
Uveitis
To prevent corneal graft rejection
NOT IN RED EYE - might be herpetic
Binocular ishcaemic neuropathy
Haemorrhage
Monocular ischaemic neuropathy
Anterior ischaemic optic neuropathy
Side effects of steroids
Cataract, glaucoma, exacerbation of virus
Gastric ulcers, immsupp, osteoporosis, diabetes, weight gain, psych effects
Symptoms of glaucoma
Progressive optic neuropathy (loss of optic nerve fibres) = enlarged cup
Central vision preserved
Raised IOP
Treatment of glaucoma
Prostanoids - Latanoprost
B blockers - timolol (blocks CB)
CA inhibitor - acetazolamide (blocks CB)
alpha agonist - Brimonidine (increase outflow)
Parasympathomimetic - Pilocarpine (increase outflow)
Treatment for endophthalmitis
Intravitreal antibiotics
Diagnostic drops
Fluorescein - shows abrasions
Mydriatic drops
Tropicamide (block para to iris)
LA
Blocks Na channels and impedes nerve conduction
When is LA used?
FB removal
Tonometry (pressure)
Corneal scrape
Comfort
Side effects of tropicamide
Blurring
AACG (come back if headache)
Side effect of ethambutol
Optic neuropathy (colour then peripheral vision)
Side effect of chloroquine
Maculopathy (bullseye)
Side effect of amiodarone
Optic neuropathy (whorl opacities) = blurred vision, halos
