Ocular Pharm Flashcards
How much of drops are lost to evaporation
25%
Bioavability
The percent of unchanged drug that gets to the desired site.
Tear layer characterisitics
Lipid=lipid soluble. Aqeuous=water mucus=both
Corneal layer characteritis
End and epi=lipid. Stroma=water
What type of drugs with penetrate best
small, uncharged, lipid soluble molecules. Most formulated as weak bases.
What route has the best bioavaliblity
IV
Where are parasympathetic cell bodies located
Cranial sacral. PCS.
Where are sympathetic cell bodies located
Thoracic-lumbar.
NT for preganglionin in Para
Acetylcholine
NT for pre ganglion in symp
Acetylcholine
Which autonomic pathway has longer post ganlgionic
sympathetic
NT for post ganglion Para
acetylcholine
NT for post ganglion sympathetic
norepinerphein and epinerphine.
Functions of para
SLUDGE
Dilator of iris sympathetic function and receptor
alpha 1. Dilates
CB vasculature SNS function and receptor
Alpha 2. Decreaes aqeuosu
CM vascualrture SNS function and recptor
B2. relaxes
TM SNS function and recetpro
B2. Increases outflow
NPCE SNS function and receptor
B1 and B2. Increases outflow.
What structures in the eye receive Parasympathetic innervation?
Iris, CB, and lacrimal gland.
Pilocarpine
Direct acting cholinergic agonist. First every glaucoma drug. Stimulates the longitudinal fibers of the CB which pulls on the scleral spur and opens up the TM.
What pilio do you use with Aidies
0.125%
SE of pilocarpine
brow ache, HA, myopic shift, can cause angle closure or RD or cataracts.
Edrophonium (Enlon)
Used to diagnose MG. If ptosis improves know it is MG.
Neostigmine (prostigmin)
Treatment for MG or limb strength evaluation.
Echothiophate (phospholine)
Irreversible ACHE inhibitors. Can be used to diagnose or treat accommodative esotropia.
Pyridostigmine (mestinon)
Used to treat MG.
Pralidoxime
Used for overdose of indirect cholinergic agonists. Only works with irreversible (echothiphate)
Scopalamine
Cholinergic antagonist. Used for motion sickness. High incidence of crossing BBB.
Which cholinergic antagonist has the fastest onset and shortest duration?
tropic amide
Atropine
Most potent.
Who should you dilate with caution?
THINK. Thyroid. Iris fixed IOL. Narrow angle. Kids (DS)
which drug do you use for anterior uvieits?
homatropine. It dilates the iris, reduces pain, and stabilizes the blood aqueous barrier.
How long does Atropin work
7-10 days
How long does scopolamine work
3-7 days
How long does homatropine work
1-3 days
How long does cycloplegia work
24 hours
How long does tropic amide work
4-6 hours.
Botox
Anticholingeric and NMJ.
Norephinerphein vs. Epinerphine
Norepinephrine does not work on B2 receptors.
Phenylephrine
Sympathetic agonist. 2.5% routinely used for dilation. Acts on alpha 1 receptor with no affect on B. Allows dilation without any SE.
Which is the weird on in sympathetic NS
Alpha 2
When to give BB
In the morning
Who should you be cautions with BB
diabetic (hid hypo signs), lungs, Heart, hyperthyroidism, MG.
Short term escape
lowers initially and then raises
Long term drift
IOP starts to gradually rise
Do you get short term escape and long term drift with BB
YES.
Cosopt
Timolol and dorzolamide
Combigan
Timolol and briminoladine
Alpha 2 agonist action
Act to decrease production and increase outflow
SE of CAI
Aplastic anemia, thrombocytopenia, agranuloctyopenia, metallic taste, metabolic acidosis.
CI for CAI
SULFA BASED
Prostaglandin Analogs
Acts on FP receptors (PGF2alpha) on the ciliary muscle which causes reduction of neighboring collage (using MMP), decreasing resistance with the uveoscleral meshwork. Also acton on skin receptors and hair follicles.
When to dose prostaglandins
bedtime
SE of prostaglandins
Iris herterochromia, darker lashes, dark pigment around the eyes.
Reduction in IOP of glaucoma drugs
Apraclondine (30-40), prost (33), Pilo (30). BB (25), biminodine and dorzolamid (18).
How do topical ocular anesthetics work
Block nerve conduction and change membrane potential by stopping the influx of Na.
Amides
Go inside. Injectable. Liver.
Esters
topical. Metabolized locally.
Proparacaine
Ester anistehtic. Lasts 10-20 minutes.
Fluoress
Fluorescent and benoxinate (another topical anesthetic)
How do antihistamines work
block the cell receptors the histamines act upon
Emedastine
H1 antihistamine. Use with moderate allergic conj.
Mast cell stabilizers
Not good for acute but use chronically. Stops mast cells from becoming degranulated by stopping CA influx.
SE of corticosteroids
Risk of secondary infection, Cataract, ocular HTN (junk not cleared out and decreased outflow)
What do corticosteroids do?
Stop phosophilapase A2.
Soft Steroids
FML and Loteprednol.
NSAIDS
COX blockers so stop Leukotriens, thrombin,
Where is FA dye injected
Brachial vein
How long from injection to eyes
10-20 seconds
Who is glycine CI in?
Diabetics. Use isosorbide instead.
Methylcellulose
used to increase viscosity of AT and allow more contact time with cornea
