Pharmacology Flashcards
What kind of drugs do the corneal epithelium like?
Lipophilic
What kind of drugs do the corneal stroma like?
Hydrophilic
Which drug has both a lipophilic and hydrophilic component
Chloramphenicol
How can a drug be made more lipophilic?
Addition of an alcohol
How can drugs be made more hydrophillic?
Addition of a phosphate group
Which steroid is given for an uninflamed cornea?
Prednisolone acetate
Acetate group - hydrophobic so good in the epithelium.
Which steroid is given for corneal disease?
Prednisolone phosphate.
Phosphate- hydrophillic so good in the stroma
How can hydrophilic drugs be better absorbed into the stroma?
Benzalkonium.
It disrupts the lipid layer of the tear film
What is the name of the benzalkonium?
Bimatoprost
How are topical steroids incorporated systemically?
Tears spread the topical drug into the punctum which leads to the nasopharynx so is swallowed
How can steroids be prevented from spreading systemically?
Pressing on punctum (nasal side) stops the drops getting to the nasopharynx.
What side effect may be present with topical steroids?
Bad taste in mouth
When are steroids given intravitreally?
Wet macular degeneration
When are topical steroids used? (3)
Post op cataracts to prevent inflammation
Uveitis
Preventing corneal graft rejection
What are the signs of uveitis?
Injecting vessels
Photophobia
Misshapen pupil
WBC on slit lamp
What signs are bad in a corneal graft?
New blood vessels.
Graft rejection line - darker infiltrate inferiorly
What are the local side effects of steroids?
Cataracts
Glaucoma
Exacerbation of viral infection
In what infective ocular process should steroids not be used?
Viral conjunctivitis
What systemic side effects can steroids cause?
Osteoporosis
Weight gain
Diabetes
Gastric ulceration
What dosage of steroids should be given for temporal arteritis?
80mg
high!
What is glaucoma?
Progressive optic neuropathy resulting in loss of peripheral vision
What are the risk factors for getting glaucoma?
Family history
Over 40
Steroids
Diabetes
What is thought to cause glaucoma?
A raised intracranial pressure
What investigation needs to be done in glaucoma?
Visual field test.
If double sided then driving is not allowed.
Which glaucoma treatment can be given by drops?
Pilocarpine - miotic
Latanoprost
Timolol - B blocker
What is acetazolamide?
reduces ICP by reducing production of aqueous humour. Given IV/IM.
What is important to note with latanoprost?
Can change the colour of the iris
Which drug is given first in glaucoma?
Prostanoids e.g. latanoprost
What is anti-VEGF given for?
To prevent new blood vessels from forming
When are drugs given intra-vitreally?
Endophthalmitis
Why can local anaesthetic not be used regularly?
Stops epithelium from regenerating so prevents healing
How and why is fluorescein used?
With a blue light.
Shows corneal abrasion
What is tonometry?
Measures pressure
How can fluorescein be used to diagnose nasolacrimal duct obstruction?
Will run out of lateral sides of eye instead of into the puncture.
How do mydriatics work?
Cause pupil dilation by blocking parasympathetic (CN III) supply to ciliary muscles
What damage can ethambutol cause to the eye?
Optic neuropathy
What drug can cause maculopathy?
Chloroquine.
Hydroxychloroquine now used.
What drug can cause tears to turn red?
Rifampacin
What does amiodarone cause in the eye?
Corneal verticullata
Looks like a whirl of spindle like cream lines in the pupil
