Diagnostic Pharm Agents Flashcards
3 units of availability
- SDU Single dose unit
- Multiple dose preserved unit
- Multidose preservative free (MDPF)
Single dose unit
One opened, should be used and discarded right away. Contains no ingredient to stop microbial growth. AKA preservative free (PF)
Multiple dose preserved unit
Intended for repeated use
Contains preservative, a chemical with antimicrobial agent. Will kill or limit microorganism growth.
Most common preservative in eye drops: Benzalkonium Chloride (BAC or BAK)
Most common preservative in eye drops:
Benzalkonium Chloride (BAC or BAK)
Multiple dose preservative free unit
For repeated use. Has one way valve that dispenses one sterile drop only. The tip closes after each use and filter protects solution from airborne microorganisms.
6 Formulations
Ophthalmic solution Ophthalmic suspension Ophthalmic gel Ophthalmic emulsion Ophthalmic ointment Ophthalmic preparations (sterile)
Ophthalmic solution
Aqueous solution containing saline and buffering salts to maintain pH from 5-8. Comfortable upon instillation, allows solution to be stored for a long period (2 years).
Many contain polymers (cellulose commonly) or viscolizers. Viscosity depends on polymer used and amount.
Ophthalmic suspension
Heterogenous compound- contains solid particles dispersed in solute to increase contact time. Milky appearance. Must shake to disperse particles from sedimentation. Particles are small enough to not irritate surface of the eye.
Ophthalmic gel
Highly viscous solution with saline aqueous base and micoadhesive polymer such as polycarbophil. Bioadhesion attaches drug to biological tissue and increases contact time on ocular surface.
*Blurs vision- take before bed
Ophthalmic emulsion
Prepared by dissolving active ingredient into oil phase. Emulsifying agents and water (two or more liquids) are vigorously mixed to form uniform water-in-oil emulsion.
Preparation reminds intact and does not separate. Has milky appearance.
Ophthalmic ointment
Non-aqueous preparation. Base is oily such as petrolatum, paraffin oils, lanolin
Melting point near body temp.
2-4x longer contact time.
Ophthalmic preparations (sterile)
Prepared under sterile conditions by law. By Rx only
2 forms of presentation to ocular surface
Instillation of eye drop
Application of gel or ointment
How to instill eye drop into eye
Delivered to lower cul-de-sac or inner canthus.
Avoid cornea- will bounce off.
Close eyes for short time.
once eye drop is instilled, it is absorbed into
Cornea and conj. 5% of Active drug absorbed. only 1% reaches aqueous because it gets washed out by aqueous humor through trabecular meshwork and outflow.
How much of an eye drop is absorbed? Where does the rest go
5% absorbed into cornea/conj. 1% reaches aqueous.
95% passes down to nasolacrimal duct or wiped from surface. (systemic circulation)
3 things to check before eye drop instillation
Brand name
Concentration
Expiration date
How to document eye drop
Drug name and conc
# of drops instilled
Time of instillation
How long to hold puncta for punctal occlusion
1-3 mins
What tab do you document eye drops on
Posterior segment tab
Proparacaine Hydrochloride
- What kind of acid ester
- What percentage
- lasting time
- Main site of action
- MOA
- Affects on ocular surface
- M Aminobenzoic acid ester
- 0.5% ophthalmic solution
- lasts 10-20 mins. Very fast acting topical anesthetic
- Nerve cell membrane
- Blocks sodium ion permeability, inhibiting action potentials. Changes in phospholipid bilayer of cell membrane slows or completely blocks nerve signal.
- Affect on surface is dose dependent. Anesthetizes surface, decreases blink reflex, removes touch sensation.
Why do you instill proparacaine before mydriatic or cyclo drops?
Decrease stinging
Decrease lacrimation and wash out
Opens intracellular spaces and aids in drug penetration
Are mydriasis and cycloplegia clinical indications for proparacaine?
What is?
NO!
Tono, gonio, suture removal, foreign body removal, punctal plug insertion/removal, cataract.
Proparacaine contraindications
Hypersensitiives are known.
Proparacaine warningd
Prolonged use can cause permanent corneal opacification with vision loss.
May delay wound healing
Cytotoxicity upon instillation.
Safety with proparacaine
- Pregnancy category
- Lactation
- Peds
- Geriatric
Pregnancy category C: No animals tested. Unknown affect to fetus or pregnant women.
Unknown lactation
Pediatric use and geriatric use: Safe
Ocular side effects of proparacaine
None
Stinging, burning, lacrimation, conj redness.
RARE: Intense, diffuse epithelial keratitis (ground glass appearance) Epithelium sloughing
Fluress/Fluorox/Flucaine Benoxinate Hydrochloride (oxybuprocaine)
- Shelf life
- Components
- Ocular side effects
- Clinical indications
- 18 months
- 0.4% benoxinate, 0.25% fluorescein sodium
- Burning, stinging, red eye, blurred vision (rare)
- used to assess integrity of ocular surface or anesthetize eye during tono
