Pharmacology Flashcards
Why does the topical route of admission pose difficulties?
The drug has to both be lipophilic and hydrophilic in order to pass through the aqueous components and the lipid bound epithelium.
Give an example of both a lipophilic and hydrophobic drug?
Chloramphenicol
Why does an inflamed eye improve the uptake of drugs?
Inflammation creates gaps between the epithelial cells allowing less lipophilic drugs a site of entry.
Why do ointments have a higher uptake of the drug through the eye than drops?
Ointments are not washed or blinked away as easily so stay for longer on the surface of the eye.
In regards to steroids what can be added to make them more hydrophilic?
Phosphate groups
In regards to steroids what can be added to make them more lipophilic?
Acetate groups
Give an example of a hydrophobic steroid.
Prednisolone Acetate
When is prednisolone acetate used and why?
Used post operatively
Good penetration of the eye
Give an example of a hydrophilic steroid and explain how this impacts its usage.
Prednisolone Phosphate
Doesn’t penetrate the eye so used for surface level inflammation
What drug increases the uptake of other drugs through the eye?
Benzalkonium
How does benzalkonium work?
It disrupts the lipid bilayer allowing the drug entry.
How can topical applications be systemically absorbed?
The lacrimal duct empties into the nasopharynx.
How can systemic absorption be limited in topical applications?
Pinch the bridge of the nose to obstruct the lacrimal duct for a period of time after application.
When treating infections of the posterior eye why can drugs not be administered systemically?
The Blood retinal barrier prevents the drugs from entering the optic environment.
How are drugs administered to the posterior chamber?
Intravitreal injection
How are drugs administered into the front of the eye?
Intracameral injection
What anti inflammatories are commonly used for the eye?
Steroids
NSAIDs
Antihistamines
Mast Cell stabilisers
When are steroids used?
Post Operative Cataracts
Uvietis
Prevention of corneal graft rejection
When are IV steroids used in a clinical setting?
Suspicion of temporal arteritis
What are some local effects of steroid use?
Cataracts
Glaucoma
Exacerbation of viral infection - corneal melt
What are some systemic effects of steroid use?
Gastric ulcers
Osteoporosis
Weight gain
List some of the commonly used steroid in order from least to most potent.
FML
Prednisilone - Phosphate
Beclamethasone
Dexamethasone - Acetatae
Glaucoma can be completely stopped. T/F
False
We are only able to slow the progression of the disease.
List the types of drugs available for the treatment of a glaucoma.
Prostanoids Beta Blockers Carbonic Anhydrase inhibitors Alpha Adrenergic Agonist Parasympathimimetics
Give an example of a Prostanoid.
Latanoprost
How do Prostanoids work?
Latanoprost
Increases the drainage
1x daily
How do Beta Blockers work?
Tinnolol Betaxolol
Reduces production of aqueous fluid.
Give an example of beta blockers.
Tinnolol
Betaxolol
Give some examples of Carbonic anhydrase inhibitors
Dorzolamide - Topical
Acetazolamide - Systemic
How do Carbonic Anhydrase inhibitors work?
Reduce the production
When is Acetazolamide used?
In an acute glaucoma
Give an example of an Alpha Adrenergic Agonist.
Brimonidine
How do Alpha Adrenergic Agonists work?
Reduce production
Widens the trabeculae
What drug used in the treatment of Glaucoma is contraindicated in children?
Alpha Adrenergic Agonists.
What are some of the side effects of Alpha Adrenergic Agonists?
Red eye
Many people become allergic
In adults causes extreme fatigue
Give an example of an Parasympathomimetic
Pilocarpine
How do parasympathomimetic work?
Massively constrict the pupil
What is a commonly used combination therapy?
Dorzolamide
Timolol
What is the treatment for someone with Wet Macular Degeneration?
Intravitreal Anti-VEGF
What is the most commonly used diagnostic dye?
Flourescin
When is fluorescin used?
Corneal Abrasions
Dendritic Ulcers
Identify leaks
Diagnosing Naso-Lacrimal duct obstruction
How do local anaesthetics work?
They block Na+ channels so prevent the conduction of action potentials across the axon.
When are local anaesthetics used?
Foreign Body Removal Tonometry Corneal Scraping Comfort Cataract surgery
What is the name of the pupil dilating drugs?
Mydriatics
List two commonly used mydriatics.
Cyclopentolate
Tropicamide
How do mydriatics work?
They over stimulate the sympathetic system resulting in dilation of the pupil.
What drug used to treat bradycardia can be used topically to dilate the eye, but why is it not widely used?
Atropine ACh competitor
Effects last too long a time
What drug used in the treatment of TB has side effects affecting the eye?
Ethambutol - optic nerve neuropathy
What drug used in the treatment of heart failure has side effects affecting the eye?
Digoxin - causes yellow tinting
Which drug used in rheumatology has some evidence of side effects after long term usage?
Hydrochloroquine
Pinpoint Maculopathy
