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. Aqueous=water soluble, mucus=both water/lipid soluble
Corneal layer characteristics for drug penetration
Endothelium and epi=lipid soluble. Stroma=water sol
What type of drugs will penetrate best
small, uncharged, lipid soluble molecules. Most formulated as weak bases.
What route has the best bioavailablity
IV route
Where are parasympathetic cell bodies located
Craniosacral. PCS.
Where are sympathetic cell bodies located
Thoracic-lumbar.
NT for preganglionin in Para
Acetylcholine, has longer preganglionic neuron
NT for pre ganglion in symp
Acetylcholine, has shorter preganglionic neuron
Which autonomic pathway has longer post ganglionic
sympathetic
NT for post ganglion Parasympathetic
acetylcholine
NT for post ganglion sympathetic
norepinephrine and epinephrine.
Functions of parasympathetic nervous system (muscarinic)
Rest/digest
Wet!!
bronchoconstriction/ miosis (constriction)
SLUD = salivation, lacrimation, urination, defecation
Dilator of iris sympathetic function and receptor
alpha 1. Dilates
CB vasculature SNS function and receptor
Alpha 2. Decreaes aqeuosu
Ciliary Muscle vasculature SNS function and receptor
B2. relaxes
Trabec Mesh SNS function and receptor
B2. Increases outflow
NPCE SNS function and receptor
B1 and B2. Increases outflow.
What structures in the eye receive Parasympathetic innervation?
Iris, ciliary muscle, and lacrimal gland.
Pilocarpine
_% IOP reduction? how many times per day?
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 to increase outflow and reduce IOP
30% reduction
short half life so 4x/day
What pilo do you use with Adies tonic pupil
0.125%
Side fx of pilocarpine
brow ache, HA, myopic shift, can cause angle closure or RD or cataracts.
“dimmed vision” in cataracts
Edrophonium (Enlon)
Used to diagnose MG– Tensilon test. If ptosis improves 1-2 min after injection = (+) 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)
to treat MG.
Pralidoxime
- Used for overdose of indirect cholinergic agonists. Only -works on IRREVERSIBLE AchE agents (echothiphate)
- binds to irreversible AchE agent, to allow acetylcholinesterase to break down Ach
- antidote for overtreatment of MG
Scopolamine (effects, side fx, contraindication)
Cholinergic antagonist. Used for motion sickness. High incidence of crossing Blood brain barrier = likely CNS toxicity
side fx: hallucination, amnesia, unconsciousness, confusion, restlessness, incoherence, vomit, urinary incontinence
Which cholinergic antagonist has the fastest onset and shortest duration?
tropicamide
Atropine
- onset
- duration
- used for what tx?
- side fx
- caution in what population
Most potent.
- 60 to 180 minutes onset
- 7 to 12 days duration for cycloplegic fx
- amblyopia tx– put on good eye = Penalization
- safe; dangerous if incorrect dosage
- sick, handicapped, Down Syndrome, elderly, small kids under 3
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 cyclopentolate 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 Beta blocker
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 = no depolarization
Amides anesthetics
Go inside. Injectable. Liver.
longer duration of action
Esters anesthetics
All topical anesthetics. Metabolized locally. short duration of action
Proparacaine
Ester anistehtic. Lasts 10-20 minutes.
Fluoress
Fluorescent and benoxinate (another topical anesthetic)
How do antihistamines work
block type 1 hypersensitivity rxn/ the cell receptors the histamines act upon
Emedastine
H1 antihistamine. Use with moderate allergic conj.
Mast cell stabilizers
Not good for acute but use CHRONIC. 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
75% of topical drug goes where? 3 types of routes
- drainage into nasolacrimal apparatus
- absorption into systemic circulation by conj/lid vasculature
- penetration into cornea
to cross cornea, drugs need to have what properties
lipophilic and hydrophilic
topical route is to:
Pros:
Cons:
mucosa, conjunctiva, cornea, epidermis
pros: at site of desired effects
cons: site irritation, systemic side fx
Oral route pros/cons
pro: simple dosage, easily administered, time released
cons: GI distress, drug degradation, absorption problems
Subconjunctival route injects bw __ & __
pros/cons
inject b/w conjunctiva & sclera
pros: Rapid, effectively absorbed
cons: fear, pain, inflammation
intravenous route
pros/cons
into vein
pro: Highest bioavailability, Very rapid, dose accuracy, bypass digestive tract
cons: danger of cardiotoxicity (bolus), sterility
intramuscular pros and con
pro: rapid, controlled absorption
cons: pain, necrosis
function of sympathetic nervous system
fight/flight
DRY
bronchodilation/ mydriasis
decrease in secretions
cholinergic receptors in eye (location, receptor, general effects, innervated by CN __)
CAMS = ciliary muscle/acc, Miosis/sphincter
Iris sphincter = M3 = miosis = CN3
Ciliary muscle = M2, M3 = accommodation = CN3
Lacrimal gland = M2, M3, increase tear production = CN 7 (reflex, emotional)
adrenergic receptors in eye (location, receptor, general fx)
iris dilator = alpha-1 = dilation trabecular meshwork = beta-2 - relaxation, increase outflow ciliary muscle = beta -2 = relaxation, opposes accommodation NPCE = B2 > B1 = increase aqueous formation CB vasculature (MACI) = alpha2 = constricts, reduce aq formation
Cholinergic agonists for treatment of __ & ___
glaucoma, accommodative esotropia
acc ET b/c acts on ciliary muscle and decreases amt of CNS stimulation to ciliary muscle = decrease convergence
what drug best to use during angle closure?
pilocarpine
especially before LPI b/c drug will make iris tight and LPI is more effectively done
__% pilocarpine to differentiate CN 3 palsy vs sphincter tear in fixed,dilated pupil
1%; CN 3 palsy will constrict w pilocarpine
what are indirect cholinergic agonists
anticholinesterase; inhibit acetylcholinesterase that normally breaks down ach
- Edrophonium (Enlon)
- Neostigmine (Prostigmin)
- Echothiophate (Phospholine)
- Pyridostigmine (Mestinon)
What are cholinergic antagonists used for?
cycloplegic refractions
pupillary dilation
managing uveitis
blocks Ach @ muscarinic sites in CB and iris
functions of cholinergic antagonists
acts like sympathetic pathway
STop ACH (Scopolamine, Tropicamide, Atropine, Cyclopentolate, Homatrophine)
ASH CT (‘city”) MEMORIZE IN THIS ORDER!
**NOT USED FOR GLAUCOMA TX
tropicamide: onset for mydriatic and cycloplegic effect, duration?
25 min onset, lasts 6 hrs
what does atropine toxicity cause?
#1 dry mouth dry flushed skin, rapid pulse, disorientation, fever b/c CNS effects
which cholinergic antagonist has fastest onset and shortest duration of cycloplegic fx
Cyclopentolate
cyclopentolate’s max effects at what onset for mydriatic and for cycloplegic
20-45 min (mydriatic) 45 min (cycloplegic)
homatropine functions
dilates pupil (not the best)
keeps iris mobile so good for posterior synechiae pts
reduce pain b/c paralyze sphincter and ciliary muscles
stabilize blood aqueous barrier by constricting iris and CB vasulature
what is anticholinergic toxicity
hot as a hare, red as a beet, dry as a bone, mad as a hatter, blind as a bat
what is MOA of Botulina Toxin (Botox)
blocks release of Ach at NEUROMUSCULAR JUNCTION to inhibit muscle contraction
prevent wrinkle
Adrenergic agonists used for what
dilation conjunctival constriction manage minor allergic conditions temporary ctrl of IOP spikes tx of POAG
Norepinephrine vs epinephrine
Norepi does NOT act on Beta-2 receptors
Phenylephrine 2.5% uses
- alpha-1 agonist
- dilates w/o cyclo
- palpebral widening - muller’s muscle retracts upper lid
- tells scleritis vs episcleritis (blanched conj vessels/white vessels = episcleritis b/c vessels superficial)
- Horner’s syndrome (horner pupil dilates, normal pupil doesn’t)
Phenylephrine 10% uses
break posterior synechiae
Phenylephrine 10% contraindications
- Think: HEART = cardiovascular side fx (HTN, cardiac arrhythmias)
- Graves disease (has too much sympathetic already–phenyl will make it worse)
- TCA (tricyclic antidepressants)
- atropine intake
- MAOI intake
what does Naphazoline (Naphcon A) & Tetrahydrozoline (Visine) do
- topical ocular decongestant (constrict conj BV)
- acts on Alpha-1 so overuse can lead to dilated pupils
Alpha-2 agonists
Brimonidine (Alphagan 0.20%), Apraclonidine
- decrease aqueous humor production
- increase uveoscleral outflow
- lower IOP and long-term tx of glaucoma
neuroprotective properties (2 meds)
protects optic nerve
Betaxolol
Brimonidine
Brimonidine: uses, side fx, contraindication
side fx: follicular conjunctivitis (inferiorly), DRY MOUTH
cause miosis, reduce glare, halo
contraindications: MAOI takers
Alphagan 0.2% vs Alphagan P: the P has preservatives and conc 0.1%
Apraclonidine
- Iopidine
- alpha 2 agonist
- 30-40% IOP reduction
- controls IOP spikes b4 & after LPI, trabeculoplasty, posterior capsulotomy, acute angle closure)
- Acute use b/c tachyphylaxis (loss of effect of drug over time)
- Diagnose Horner’s syndrome
Horner’s syndrome
small ptosis b/c defect Muller muscle Lack of Sympathetic Dilation lag (delayed dilation) + ptosis
Med to test Horner’s syndrome
Apraclonidine or Cocaine
Apraclonidine: no fx on normal pupil, dilates the miotic/horner pupil
Cocaine: dilates healthy eye, no effect on miotic/horner eye
Hydroxyamphetamine or phenylephrine
if healthy or preganglionic is damaged, , hydroxamphetamine acts on POSTGANGLIONIC NEURON -> releases norepinephrine + mydriasis. if don’t dilate, postganglionic neuron is DAMAGED
phenylephrine 1% dilates postganglionic horner’s syndrome
Name 5 beta-blockers
Timolol Betaxolol Levobunolol Carteolol Metipranolol
Beta-blockers side fx
CNS: disorientation, depression, fatigue
Cardiovascular: bradycardia, arrhythmias, syncope
Pulmonary: dyspnea, wheezing, bronchospasm
Digestive (GI): nausea, vomit, diarrhea, abdominal pain
Reproductive: erectile dysfunction
Betaxolol differs from other beta-blockers b/c
targets only B1
best to take timolol
daytime
which beta-blocker has crossover effect
Timolol: unilateral use will also reduce IOP in opposite eye
beta-blockers do what to hyperthyroidism
mask signs and symptoms
beta-blocker does what to myasthenia gravis pts
exacerbates
Carteolol
“Cart Heart”
reduce cholesterol in hypercholesterolemia
less side fx than other beta-blockers
which beta-blocker has intrinsic sympathomimetic activity?
carteolol
reduces nocturnal badycardia
Betaxolol (Betoptic-S)
Beta1 specific *remember beta1 involves heart
can worsen heart failure
Levobunolol
Similar to timolol
Metipranolol
not used anymore
Name cholinergic agonist (direct-acting)
Pilocarpine
MOA of cholinergic agonist, alpha-adrenergic agonist, beta blocker, CAI, Prostaglandin in terms of glaucoma
cholinergic agonist: Pilocarpine; increase corneoscleral outflow
alpha-adrenergic agonist (alpha 2 agonist); reduce production/ increase uveoscleral outflow
beta-blocker: reduce production
CAI: reduce production
Prostaglandin: increase outflow via uveoscleral route
CAI MOA, topical names, oral names
reduce aqueous production by inhibiting carbonic anyhydrase = blocking bicarb flux into posterior chamber
Topical: Brinzolamide 1% (Azopt), Dorzolamide 2% (Trusopt)
Orals; Acetazolamide (Diamox), Methazolamide (Neptazane)
Oral CAI side fx/ contraindications
Common: Metallic taste, tingling hands/feet, metabolic ACIDOSIS
most serious: Thrombocytopenia, agranulocytosis, aplastic anemia
fatal: bone marrow suppression and plastic anemia
other side fx: malaise, fatigue, weight loss, anorexia, impotence, depression, diarrhea, myopic shift
Contraindication: COPD, pregnancy, sulfa allergy
contraindicated in pregnant
FA2TSI: Fluoroquinolone AmiNOglycosides (cause N Ototoxicity) Acutane Tetracyclines Sulfa Ibuprofen
first line of tx for POAG
Prostaglandins
Name prostaglandin analogs
Latanoprost (Xalatan 0.005%)
Bimatoprost (Lumigan 0.03%)
Travoprost (Travatan 0.004%)
function of prostaglandin
27-35% IOP reducation
prostaglandin contraindications
CME
active inflammation (uveitis)
hx herpes simplex keratitis
amide anesthetic
- name
- metabolized by what organ
Lidocaine
metabolized by liver
Name ester anesthetic, onset, duration
Proparacaine/ Benoxinate, 10-20 sec onset, 10-20 min duration
Fluoress is combination of what two drugs
Benoxinate + fluorescein
Steps to Type 1 hypersensitivity rxn
1) 1st exposure to antigen -> IgE antibodies produced but No symptoms occur
2) IgE binds to mast cells and basophils
3) antigen reexposure -> binds IgE/mast cell complex -> opens Ca channels
4) Ca influx -> depolarizes cell -> degranulation of mast cell -> releases histamine/other inflammatory mediators into blood
5) allergic symptoms -> binds histamin to histamine receptors
name of antibody in type 1 hypersensitivity
IgE
“IgE allergee”
Mast cell stabilizers effective in what ocular conditions?
Chronic allergic conjunctivitis
Vernal conjunctivitis
Atopic keratoconjunctivitis
Name Mast cell & antihistamine combinations
Bepotastine (Bepreve) Epinastine (Elestat) Ketotifen (Zaditor) Olopatadine 0.10% (Patanol) Azelastine (Optivar) Olopatadine 0.20% (Pataday)
effective in long-term oc itching/allergic conj, acute symptoms
Anti-inflammatory agents name 2 types
Corticosteroids
NSAIDs
corticosteroids
anti-inflammatory/ immunosuppressive
inhibits phospholipase A2
corticosteroids side fx
increased risk of secondary infxn
PSC catarcts
glaucoma
Potent steroids names
Prednisolone 1% Acetate
Rimexolone (Vexol)
Difluprednate (Durezol)
Dexamethasone 0.1%(Maxidex)
Soft steroids
Loteprednol 0.5% (Lotemax)
Fluorometholone 0.1% (FML)
less likely cause spike in IOP
NSAIDs names
Diclofenac sodium 0.1% (Voltaren) Ketorolac Tromethamine 0.4% (Acular LS) Nepafenac 0.1% (Nevanec) Bromfenac 0.09% (Xibrom, Bromday) Flurbiprofen 0.03% (Ocufen)
Voltaren & Acular how many times per day
QID
Nevanec dosed how many times
TID
Xibrom dose per day
BID
Ocufen dose per day
prior to ocular surgery
Ketorolac (Acular) only NSAID for what tx
seasonal allergic conjunctivitis
Voltaren side fx
corneal toxicity -> corneal melting -> most often in Voltaren so withdrawn from market
Ketorolac side fx
stinging upon instillation
Fluorescein evaluates what
tear film quality
epithelial defects
Rose Bengal used for
dead and devitalized cells cells w/ loss of mucous surface NOT EPITHELIAL DEFECTS evaluates herpetic corneal ulcer -> stains dendrite lesion more discomfort
Lissamine Green
dead/devitalized cells
*Dry eye evaluation
Methylene blue
stains corneal nerves, stains similar to Rose Bengal
for glaucoma filtering blebs
for lacrimal sac before dacryocystorhinostomy