pharmacology Flashcards
(32 cards)
describe the properties of the epithelium
lipophilic
hydrophobic
describe the properties of the stroma
lipophobic
hydrophilic
what things can affect corneal penetration
surface inflammation = less hydrophobic
lipid layer of tears
what must reports must steroids have to allow penetration
hydrophobic and hydrophilic capabilities
what is added to make a steroid more hydrophobic
alcohol
acetate
what is added to make a steroid more hydrophilic
phosphate
what is benzalkonium used for
preservative
disrupts the lips layer of the tear film to increase penetration
what are the common routes of drug administration to the eye
subconjunctival
subtenons
ocular injection
what are the two types of ocular injection
intravitreal
intracameral
what is use of intraviteal injection, what risk does this pose
Delivers effective concentration of drug at target site instantly BUT many drugs are toxic to retina
what drugs are delivered by intraviteal injection
anti-VEGF
antibiotics for endophthalmitis
intra-ocular steroids
what 3 things are used to treat inflammation, what are their uses
Steroids = suppress inflammation, allergy, and immune response
Anti-histamines = hayfever/ allergic conjunctivitis
Mast cell stabilisers = hayfever/ allergic conjunctivitis
what conditions require topical steroids
post-op cataracts
uveitis
prevent corneal graft rejection
what are the local side effects of steroids
cataract
glaucoma
exacerbation of viral infection
what re the systemic effects of steroids
gastric ulcer immunosuppression osteoporosis weight gain diabetes neuropsychiatric effects
give an example of an hydrophilic steroid
prednisolone phosphate
when is prednisolone phosphate used, why?
corneal disease or in conditions where low dose steroids are required
used because it has a poor penetration in non-inflammaed corneas
give an example of an hydrophobic steroid
prednisolone acetate
when is prednisolone acetate used, why?
post-op
used because it has a good penetration in non-inflammed cornea
what is the most type of diagnostic dye
fluorescein
what is fluorescein used for (6)
corneal abrasion dendritic ulcer identify leaks tonometry nasolacrimal duct obstruction angiography
what is the mechanism of action of local anaesthetic
blocks sodium channels to impede nerve conduction
give example of mydriatic drugs
tropicamide
cyclopentolate
what is the mechanism of mydriatic drugs
causes pupil dilation by blocking parasympathetic supply to iris = paralyses ciliary muscles
