Intro To Opthalmic pt 1 Flashcards
Where is the primary absorption site for eye medications?
Cornea
Give 2 reasons why the cornea is unique
- Avascular
2. Dual nature = lipophilic + hydrophilic
The cornea has 5 layers but only the _________ and ________ contribute to absorption
Epithelium
Stroma
The _______ of the cornea is lipophilic and the _______ is hydrophilic
Epithelium
Stroma
The __________ accounts for less than 1/5 of drug absorption; because it is highly vascularized the drug can reach systemic circulation
Conjunctiva
T/F: redness of the eye increases drug absorption into the eye due to increased vascular presence
False
- it decreases absorption in the eye but increases systemic absorption
Miosis
Contraction Iris Sphincter PNS Cholinergic
Mydraisis
Contraction Radial muscle Iris SNS Adrenergic
What is the role of the ciliary body?
- Aqueous humor production
- Ocular source of drug metabolizing enzymes
- No tight junctions = passage for systemic drugs
If the ciliary body is inflamed, how will the patient present?
- Ciliary body spasm = fluctuating vision, pain and photophobia
- May induce cycloplegia to reduce pain (paralyze the ciliary body)
- Prostaglandins may result in pupillary constriction
_________ ___________ accounts for why darker eyes take longer to respond to lipophilic drugs
Pigment absorption
__________ humor circulates with thermal differential
Aqueous
What is a concern with administration of digitalis, quinine, methyl alcohol?
Renal toxicity
What is the concern with administration of ethambutol, sulfonamide, vit A & digitalis?
Optic nerve toxicity
_________ preservatives are ionically charged and disrupt cell membranes
Bacteriocidal
________ preservatives are those that disrupt metabolic processes
Bacteriostatic
Artificial tears that contain preservatives should be limited to use only ______ times per day
4 to 5
pH ranging from _____ to _____ is tolerated in the eye for comfort
6.5 - 8.5
Ophthalmic solutions are typically _____ in terms of tonicity
Hypotonic
Polymers are added to eye drug formulations to _________
Increase viscosity to create a “shielding” effect to allow for more contact time on eye
What type of solutions are used to draw water from the ocular surface?
Hypertonic solutions, like for corneal edema
Why are antioxidants included in eye drop formulations?
Prevent deterioration upon exposure to oxygen to preserve efficacy
DMSO is an example of which type of ingredient in eye drops? What is its role?
Absorption enhancer
- readily increases penetration and bioavailability by epithelial modification
- makes it “leaky”
Which preservative is highly toxic to the cornea?
Benzalkonium chloride (BK)
A ______ is defined as any agent other than active drug/preservative that is added to a formulation to achieve proper tonicity, buffering and viscosity
Vehicle
_______/_________ are used to increase lipophilic nature of a compound and tend to penetrate the cornea better
Phosphates
Hydrochlorides
_________/___________ increase hydrophilicity of a compound and tend to remain more surface-based
Alcohols
Acetates
What is a concern with contact wearers and eye drop administration?
- may act as a reservoir for the drug and may result in a slow release or corneal irritation
- sodium fluoresceine will stain soft contact lenses
Which dosage form is difficult to avoid contaminating the tube tip and may be administered alternatively with a cotton swab?
Ointments
T/F: Keeping your eye open helps reduces systemic absorption following administration fo the drug
False
Close you eyes gently or use punctal occulsion
T/F: Do not squeeze eye lids or rub the eye after administration
True
Just gently clsoe the eye
How many minutes should you wait between drop administration?
5 to 10 mins
______ should always be administered before ointments or suspensions
Drops
Bradycardia, hypotension and impotency are all signs of systemic absorption of which eye drop medication?
Beta blockers
Which eye drop may cause delirium, tachycardia and urinary retentions?
Atropine
Which eye drop class causes ototoxicity?
Aminoglycosides
T/F: most eye drop products are temperature dependent
False
Refrigeration of eye drops primarily lets the patient know what?
When the drop hits the surface
What are exceptions to refrigerating eye drops to feel it?
Prostaglandins
Antiviral
Non-preserved eye drops are ______ dose and should be discarded after opening
Single
Yellow or blue cap
Beta blocker
Red cap
Mydriatic
Cycloplegic
Green cap
Miotic
Grey cap
NSAID
Brown or tan cap
Anti-infective
White cap
Carbonic anhydrase inhibitor
Pink cap
Steroids
Order mydriatics/cycloplegics from shortest DOA to longest
Tropicamide
Homatropine
Scoplamine
Atropine
