Pharmacology Flashcards
What are the two main routes of admin of drugs to the eye?
Topical
Injection
Why can’t most systemic drugs make it to the eye?
Blood eye barrier
What two forms do topical drug preparations come in?
Drops
Ointment
Give some advantages of drops
Easier to administer
Less messy
Give some advantages of ointment
Lasts for longer
Soothes eye
What is the major side effect associated with topical drugs?
Systemic absorbance through pharynx after loss in tears
What is corneal penetrance?
The ability of a drug to pass into/through the cornea.
What regulates corneal penetrance?
Molecular weight
Hydrophobic/philic state
Do most LMW drugs have good corneal penetrance?
Yes
Where do hydrophobic drugs (lipophilic) penetrate best?
Epithelium
Where do hydrophilic drugs penetrate (lipophobic) best?
Stroma
What is the stroma?
Connective tissue
What can increase lipid soluble drug absorption?
Inflammation
What can increase corneal penetrance?
Benzalkonium- disrupts tear layers
How do you make a steroid more hydrophobic?
Add alcohol or acetate group
How do you make a steroid more hydrophilic?
Add a phosphate group
Where can injections into the eye be given?
Subconjunctival
Subtenous- Back of orbit
Intravitreal- Vitreous fluid
Intracameral- Anterior chamber
Where does a subtenous injection deliver the drug?
Back of orbit
Where does an intravitreal injection deliver drug?
Vitreous fluid
Where does an intracameral injection deliver drug?
Anterior chamber
What is a disadvantage of intravitreal injections?
Drugs often toxic to retina
What drugs are given subconjunctival?
Steroids
What drugs are given intravitreal?
Anti-VEGF
Steroids
Antibiotics
Where do you place the needle when injecting into the eyeball?
Gap between iris and retina
What are steroids used for in the eye?
Suppress inflammation- Uvitis and post op
Allergy
Suppress immune response- Corneal graft
What 4 strengths of steroid are available?
Mild- Fluorometholone
Moderate- Prednisolone phosphate
Potent- Betamathasone
Very potent- Dexamathasone or Prednisolone acetate
Give an example of a mild steroid
Fluorometholone
Give an example of a moderate steroid
Prednisolone phosphate
Give an example of a potent steroid
Betamathasone
Give an example of a very potent steroid
Dexamathasone or Prednisolone acetate
What kind of steroid is Dexamathasone or Prednisolone acetate?
Very potent
What kind of steroid is Betamathasone?
Potent
What kind of steroid is Prednisolone phosphate?
Moderate
What kind of steroid is Fluorometholone?
Mild
What are some of the local side effects of steroids?
Cataracts
Glaucoma
Viral infection
What are some of the systemic side effects of steroids?
Weight gain Osteoporosis Neuropsychotic Gastric ulcers Immunosuppresion Diabetes
What is the most commonly used antibiotic in ophthalmology?
Chloramphenicol
What drugs are used to control inflammation in the eye?
Steroids
NSAIDs
Anti-histamines
Mast cell stabilizers
What five classes of drugs are used for glaucoma?
Prostanoids- Open drain. Latanoprost
BB- Turn off tap
CAI- Turn off tap. End in -zolamide
A2 adrenergic agonists. Both. Brimonidine.
Parasympathomimetic- Shrinks pupil. Pilocarpine
What two mechanisms do glaucoma drugs have of working?
Open drain
Turn off tap
Give an example of a prostanoid and how it works
Open drain. Latanoprost
How do BB work in glaucoma?
Turn off tap
GIve an example of a CAI and how it works
Turn off tap. End in -zolamide
Give an example of an A2 adrenergic agonist and how it works
Both. Brimonidine.
Give an example of a Parasympathomimetic and how it works
Shrinks pupil to increase angle. Pilocarpine
What drug is used for diagnosis in ophthalmology?
Fluorescein
Describe how to use fluorescein
Add dye to eye
Shine blue light on
Normally blue, damage shows as green
How do LA work?
Inhibit Na channels
What do Mydriatics and sympathomimetics do?
Dilate pupil
How do you dilate the pupil?
Mydriatics and sympathomimetics
