Pharmacology Flashcards
When is the topic route of administration used in eye diseases?
Required to act on surface
Require corneal penetration
What is the cornea made up from?
Lipophilic epithelium
Lipophobic stroma
What are the chemical properties of chloramphenicol?
Lipophilic and hydrophilic
What effect can ocular surface inflammation have on the nature of the endothelium?
Reduce the hydrophobic nature
Lipid layer of tear film may impede drug penetration
What are hydrophilic drugs limited by?
Epithelium
What are hydrophobic drugs limited by?
Stroma
How are steroids made more hydrophobic?
Addition of an alcohol or acetate
How are steroids made more hydrophilic?
Phosphate
When is prednisolone acetate used?
Good penetration in uninflamed cornea
Used post-op in cataract surgery
When is prednisolone phosphate used?
Poor penetration in uninflamed cornea
Used for cornea disease or when low dose steroids are wanted
What is benzalkonium?
Used as a surfactant and bacterial agent in prescription bottles to prevent growth of pseudomonas
What is the downside/ benefit of benzalkonium?
Disrupts lipid layer of tear film which can aid penetration of drugs but also can cause a dry eye
What is bimatoprost?
Drug used to lower IOP in glaucoma
How can topical eye drops by systemically absorbed?
Tears are pumped out of lacrimal sac and can be absorbed systemically at the nasopharynx
What can be done to prevent systemic absorption of topical drugs?
Punctal occlusion
How can injections in the eyes be given?
Subconjunctival
Subtenons
Intravitreal
Intracameral
What drops are commonly given for treatment of infections?
Chloramphenicol in the drop and ointment form
Aciclovir
Ofloxacin