Ocular Pharmacology and Toxicology 2
-
Upload
lupita-moguel -
Category
Documents
-
view
230 -
download
0
Transcript of Ocular Pharmacology and Toxicology 2
-
8/8/2019 Ocular Pharmacology and Toxicology 2
1/55
Ocular pharmacologyOcular pharmacology
and toxicologyand toxicologyHatem Kalantan, MDHatem Kalantan, MDAssistant ProfessorAssistant Professor
Ophthalmology Dept.Ophthalmology Dept.College of MedicineCollege of MedicineKing Saud UniversityKing Saud University
-
8/8/2019 Ocular Pharmacology and Toxicology 2
2/55
General pharmacologicalGeneral pharmacologicalprinciplesprinciples
-
8/8/2019 Ocular Pharmacology and Toxicology 2
3/55
PharmacodynamicsPharmacodynamics
It is the biological and therapeutic effect ofIt is the biological and therapeutic effect ofthe drugthe drug (mechanism of action)(mechanism of action)
Most drugs act by binding to regulatoryMost drugs act by binding to regulatorymacromolecules, usually neurotransmittersmacromolecules, usually neurotransmittersor hormone receptors or enzymesor hormone receptors or enzymes
If the drug is working at the receptor level,If the drug is working at the receptor level,
it can beit can be agonist or antagonistagonist or antagonist If the drug is working at the enzyme level, itIf the drug is working at the enzyme level, it
can becan be activator or inhibitoractivator or inhibitor
-
8/8/2019 Ocular Pharmacology and Toxicology 2
4/55
PharmacokineticsPharmacokinetics
It is the absorption, distribution,It is the absorption, distribution,metabolism, and excretion of the drugmetabolism, and excretion of the drug
A drug can be delivered to ocular tissue as:A drug can be delivered to ocular tissue as: Locally:Locally:
Eye dropEye drop
OintmentOintment
Periocular injectionPeriocular injection Intraocular injectionIntraocular injection
Systemically:Systemically:
OrallyOrally
IVIV
-
8/8/2019 Ocular Pharmacology and Toxicology 2
5/55
Factors influencing localFactors influencing localdrug penetration into oculardrug penetration into oculartissuetissue Drug concentration and solubility:Drug concentration and solubility: the higher thethe higher the
concentration the better the penetration e.gconcentration the better the penetration e.gpilocarpinepilocarpine 11--44% but% but limited bylimited by reflex tearingreflex tearing
Viscosity:Viscosity: addition of methylcellulose and polyvinyladdition of methylcellulose and polyvinylalcohol increases drug penetration byalcohol increases drug penetration by increasingincreasingthe contact timethe contact time with the cornea andwith the cornea and alteringalteringcorneal epitheliumcorneal epithelium
Lipid solubility:Lipid solubility: because of the lipid richbecause of the lipid richenvironment of the epithelial cell membranes,environment of the epithelial cell membranes, thethehigher lipid solubility the more the penetrationhigher lipid solubility the more the penetration
-
8/8/2019 Ocular Pharmacology and Toxicology 2
6/55
Factors influencing localFactors influencing localdrug penetration into oculardrug penetration into oculartissuetissue
Surfactants:Surfactants: the preservatives used in ocularthe preservatives used in ocularpreparationspreparations alter cell membrane in the corneaalter cell membrane in the cornea andandincrease drug permeability e.g. benzylkonium andincrease drug permeability e.g. benzylkonium andthiomersalthiomersal
pH:pH: the normal tear pH isthe normal tear pH is 77..44 and if the drug pH isand if the drug pH ismuch different, this will cause reflex tearingmuch different, this will cause reflex tearing
Drug tonicity:Drug tonicity: when an alkaloid drug is put inwhen an alkaloid drug is put inrelatively alkaloid medium, the proportion of therelatively alkaloid medium, the proportion of theuncharged form will increase, thus moreuncharged form will increase, thus morepenetrationpenetration
-
8/8/2019 Ocular Pharmacology and Toxicology 2
7/55
Eye dropsEye drops
Eye dropsEye drops-- most commonmost common
one drop = 50 lone drop = 50 l
volume of conjunctival culvolume of conjunctival cul--dede--sac 7sac 7--10 l10 l
measures to increase drop absorption:measures to increase drop absorption:
--wait 5wait 5--10 minutes between drops10 minutes between drops
--compress lacrimal saccompress lacrimal sac--keep lids closed for 5 minutes afterkeep lids closed for 5 minutes after
instillationinstillation
-
8/8/2019 Ocular Pharmacology and Toxicology 2
8/55
OintmentsOintments
Increase the contact timeIncrease the contact time of ocularof ocularmedication to ocular surface thusmedication to ocular surface thus
better effectbetter effect
It has the disadvantage ofIt has the disadvantage of visionvisionblurringblurring
The drug has to be high lipid solubleThe drug has to be high lipid solublewith some water solubility to have thewith some water solubility to have themaximum effect as ointmentmaximum effect as ointment
-
8/8/2019 Ocular Pharmacology and Toxicology 2
9/55
PeriPeri--ocular injectionsocular injections
TheyThey reach behind irisreach behind iris--lenslensdiaphragmdiaphragm better thanbetter thantopical applicationtopical application
E.g. subconjunctival,E.g. subconjunctival,subtenon, peribulbar, orsubtenon, peribulbar, orretrobulbarretrobulbar
This route bypass theThis route bypass theconjunctival and cornealconjunctival and cornealepithelium which isepithelium which is goodgoodfor drugs with low lipidfor drugs with low lipid
solubilitysolubility (e.g. penicillins)(e.g. penicillins) Also steroid and localAlso steroid and local
anesthetics can be appliedanesthetics can be appliedthis waythis way
-
8/8/2019 Ocular Pharmacology and Toxicology 2
10/55
Intraocular injectionsIntraocular injections
Intracameral orIntracameral orintravitrealintravitreal
E.g.E.g. IntracameralIntracameral
acetylcholine (miochol)acetylcholine (miochol)during cataract surgeryduring cataract surgery
Intravitreal antibiotics inIntravitreal antibiotics incases of endophthalmitiscases of endophthalmitis
Intravitreal steroid inIntravitreal steroid inmacular edemamacular edema
Intravitreal AntiIntravitreal Anti--VEGFVEGFfor DRfor DR
-
8/8/2019 Ocular Pharmacology and Toxicology 2
11/55
SustainedSustained--release devicesrelease devices
These are devices thatThese are devices thatdeliver an adequatedeliver an adequatesupply of medication atsupply of medication at
a steadya steady--state levelstate level E.g.E.g.
Ocusert deliveringOcusert deliveringpilocarpinepilocarpine
Timoptic XE deliveringTimoptic XE deliveringtimololtimolol
Ganciclovir sustainedGanciclovir sustained--release intraocularrelease intraoculardevicedevice
Collagen shieldsCollagen shields
-
8/8/2019 Ocular Pharmacology and Toxicology 2
12/55
Systemic drugsSystemic drugs
Oral or IVOral or IV
Factor influencing systemic drugFactor influencing systemic drug
penetration into ocular tissue:penetration into ocular tissue: lipid solubility of the drug:lipid solubility of the drug: moremore
penetration with high lipid solubilitypenetration with high lipid solubility
Protein binding:Protein binding: more effect with lowmore effect with lowprotein bindingprotein binding
Eye inflammation:Eye inflammation: more penetration withmore penetration withocular inflammationocular inflammation
-
8/8/2019 Ocular Pharmacology and Toxicology 2
13/55
OcularOcularpharmacotherapeuticspharmacotherapeutics
-
8/8/2019 Ocular Pharmacology and Toxicology 2
14/55
Cholinergic agonistsCholinergic agonists
Directly acting agonists:Directly acting agonists: E.g. pilocarpine, acetylcholine (miochol), carbacholE.g. pilocarpine, acetylcholine (miochol), carbachol
(miostat)(miostat)
Uses:Uses: miosis, glaucomamiosis, glaucoma Mechanisms:Mechanisms: Miosis by contraction of the iris sphincter muscleMiosis by contraction of the iris sphincter muscle increases aqueous outflow through the trabecular meshworkincreases aqueous outflow through the trabecular meshwork
by longitudinal ciliary muscle contractionby longitudinal ciliary muscle contraction Accommodation by circular ciliary muscle contractionAccommodation by circular ciliary muscle contraction
Side effects:Side effects: Local: diminished vision (Local: diminished vision (myopiamyopia),), headacheheadache, cataract, miotic, cataract, miotic
cysts, and rarely retinal detachmentcysts, and rarely retinal detachment systemic side effects: lacrimation, salivation, perspiration,systemic side effects: lacrimation, salivation, perspiration,
bronchial spasm, urinary urgency, nausea, vomiting, andbronchial spasm, urinary urgency, nausea, vomiting, anddiarrheadiarrhea
-
8/8/2019 Ocular Pharmacology and Toxicology 2
15/55
Cholinergic agonistsCholinergic agonists
Indirectly acting (antiIndirectly acting (anti--cholinesterases) :cholinesterases) :
More potent with longer duration ofMore potent with longer duration ofactionaction
Reversible inhibitorsReversible inhibitors
e.g. physostigminee.g. physostigmine used in glaucoma and lice infestation ofused in glaucoma and lice infestation of
lasheslashes
can cause CNS side effectscan cause CNS side effects
-
8/8/2019 Ocular Pharmacology and Toxicology 2
16/55
Cholinergic agonistsCholinergic agonists
Indirectly actingIndirectly acting(anticholinesterases):(anticholinesterases): Irreversible:Irreversible:
e.g. phospholine iodidee.g. phospholine iodide Uses:Uses: inin
accommodativeaccommodativeesotropiaesotropia
side effects:side effects: iris cystiris cystand anteriorand anteriorsubcapsular cataractsubcapsular cataract
C/IC/I in angle closurein angle closureglaucoma, asthma,glaucoma, asthma,ParkinsonismParkinsonism
causes apnea if usedcauses apnea if usedwith succinylcholine orwith succinylcholine orprocaineprocaine
-
8/8/2019 Ocular Pharmacology and Toxicology 2
17/55
Cholinergic antagonistsCholinergic antagonists
E.g. tropicamide, cyclopentolate, homatropine, scopolamine,E.g. tropicamide, cyclopentolate, homatropine, scopolamine,atropineatropine
CauseCause mydriasis (by paralyzing the sphincter muscle) withmydriasis (by paralyzing the sphincter muscle) withcycloplegia (by paralyzing the ciliary muscle)cycloplegia (by paralyzing the ciliary muscle)
Uses:Uses: fundoscopy, cycloplegic refraction, anterior uveitisfundoscopy, cycloplegic refraction, anterior uveitis Side effects:Side effects:
local:local: allergic reactionallergic reaction, blurred vision, blurred vision Systemic: nausea, vomiting, pallor, vasomotor collapse,Systemic: nausea, vomiting, pallor, vasomotor collapse,
constipation, urinary retention, and confusionconstipation, urinary retention, and confusion speciallyspecially in childrenin children they might cause flushing, fever,they might cause flushing, fever,
tachycardia, or deleriumtachycardia, or delerium Treatment by DC or physostigmineTreatment by DC or physostigmine
-
8/8/2019 Ocular Pharmacology and Toxicology 2
18/55
Adrenergic agonistsAdrenergic agonists
NonNon--selective agonists (selective agonists (11,,22,, 11,, 22))
E.g. epinephrine, depevefrinE.g. epinephrine, depevefrin(pro(pro--drug of epinephrine)drug of epinephrine)
Uses:Uses: glaucomaglaucoma
Side effects:Side effects: headache,headache,arrhythmia, increased bloodarrhythmia, increased blood
pressure,pressure, conjunctivalconjunctivaladrenochromeadrenochrome, cystoid macular, cystoid macularedema in aphakic eyesedema in aphakic eyes
C/I in closed angle glaucomaC/I in closed angle glaucoma
-
8/8/2019 Ocular Pharmacology and Toxicology 2
19/55
Adrenergic agonistsAdrenergic agonists
AlphaAlpha--1 agonists1 agonists E.g. phenylepherineE.g. phenylepherine
Uses:Uses: mydriasis (mydriasis (withoutwithout cycloplegia),cycloplegia),decongestantdecongestant Adverse effect:Adverse effect:
Can cause significantCan cause significant increase in blood pressureincrease in blood pressurespecially in infant and susceptible adultsspecially in infant and susceptible adults
Rebound congestionRebound congestion precipitation of acute angleprecipitation of acute angle--closure glaucoma inclosure glaucoma in
patients with narrow anglespatients with narrow angles
-
8/8/2019 Ocular Pharmacology and Toxicology 2
20/55
Adrenergic agonistsAdrenergic agonists
AlphaAlpha--22 agonistsagonists E.g. brimonidine, apraclonidineE.g. brimonidine, apraclonidine Uses:Uses: glaucoma treatment, prophylaxis againstglaucoma treatment, prophylaxis againstIOP spiking after glaucoma laser proceduresIOP spiking after glaucoma laser procedures
Mechanism:Mechanism: decrease aqueous production, anddecrease aqueous production, andincrease uveoscleral outflowincrease uveoscleral outflow
Side effects:Side effects: local: allergic reaction, mydriasis, lid retraction,local: allergic reaction, mydriasis, lid retraction,
conjunctival blanchingconjunctival blanching systemic: oral dryness, headache, fatigue, drowsiness,systemic: oral dryness, headache, fatigue, drowsiness,
orthostatic hypotension, vasovagal attacksorthostatic hypotension, vasovagal attacks
Contraindications:Contraindications: infants, MAO inhibitors usersinfants, MAO inhibitors users
-
8/8/2019 Ocular Pharmacology and Toxicology 2
21/55
Alpha adrenergicAlpha adrenergic
antagonistsantagonists E.g. thymoxamine, dapiprazoleE.g. thymoxamine, dapiprazole
Uses:Uses: to reverse pupil dilationto reverse pupil dilationproduced by phenylepherineproduced by phenylepherine
Not widely usedNot widely used
-
8/8/2019 Ocular Pharmacology and Toxicology 2
22/55
BetaBeta--adrenergic blockersadrenergic blockers
E.g.E.g. nonnon--selective: timolol,selective: timolol,
levobunolol, metipranolol,levobunolol, metipranolol,
carteololcarteolol selective: betaxolol (beta 1selective: betaxolol (beta 1
cardioselective)cardioselective)
Uses:Uses: glaucomaglaucoma
Mechanism:Mechanism: reduce thereduce the
formation of aqueousformation of aqueoushumor by the ciliary bodyhumor by the ciliary body
Side effects:Side effects:bronchospasmbronchospasm (less with(less withbetaxolol), cardiacbetaxolol), cardiac
impairmentimpairment
-
8/8/2019 Ocular Pharmacology and Toxicology 2
23/55
Carbonic anhydraseCarbonic anhydrase
inhibitorsinhibitors E.g. acetazolamide, methazolamide,E.g. acetazolamide, methazolamide,
dichlorphenamide, dorzolamide, brinzolamide.dichlorphenamide, dorzolamide, brinzolamide.
Uses:Uses: glaucoma, cystoid macular edema,glaucoma, cystoid macular edema,pseudotumour cerebripseudotumour cerebri
Mechanism:Mechanism: aqueous suppressionaqueous suppression
Side effects:Side effects: myopia,myopia, parasthesiaparasthesia, anorexia, GI, anorexia, GIupset, headache, altered taste and smell, Na and Kupset, headache, altered taste and smell, Na and K
depletion, metabolic acidosis, renal stone, bonedepletion, metabolic acidosis, renal stone, bonemarrow suppression aplastic anemiamarrow suppression aplastic anemia
Contraindication:Contraindication: sulpha allergy, digitalis users,sulpha allergy, digitalis users,pregnancypregnancy
-
8/8/2019 Ocular Pharmacology and Toxicology 2
24/55
Osmotic agentsOsmotic agents
Dehydrate vitreous bodyDehydrate vitreous body which reducewhich reduceIOP significantlyIOP significantly
E.G.E.G.
glycerol 50% syrup (cause nausea,glycerol 50% syrup (cause nausea,hyperglycemia)hyperglycemia)
Mannitol 20% IV (cause fluid overloadMannitol 20% IV (cause fluid overloadand not used in heart failure)and not used in heart failure)
-
8/8/2019 Ocular Pharmacology and Toxicology 2
25/55
Prostaglandin analoguesProstaglandin analogues
E.g. latanoprost, bimatoprost, travoprost,E.g. latanoprost, bimatoprost, travoprost,unoprostoneunoprostone
Uses:Uses: glaucomaglaucoma Mechanism:Mechanism: increase uveoscleral aqueousincrease uveoscleral aqueous
outflowoutflow
Side effects:Side effects: darkening of the irisdarkening of the iris((heterochromia iridisheterochromia iridis), lengthening and), lengthening andthickening of eyelashes, intraocularthickening of eyelashes, intraocularinflammation, macular edemainflammation, macular edema
-
8/8/2019 Ocular Pharmacology and Toxicology 2
26/55
Anti-inflammatory
corticosteroid NSAID
-
8/8/2019 Ocular Pharmacology and Toxicology 2
27/55
-
8/8/2019 Ocular Pharmacology and Toxicology 2
28/55
CorticosteroidsCorticosteroids
TopicalTopical E.g. fluorometholone, remixolone, prednisolone,E.g. fluorometholone, remixolone, prednisolone,
dexamethasone, hydrocortisonedexamethasone, hydrocortisone
Mechanism:Mechanism: inhibition of arachidonic acid releaseinhibition of arachidonic acid releasefrom phospholipids by inhibiting phosphlipase Afrom phospholipids by inhibiting phosphlipase A22
Uses:Uses: postoperatively, anterior uveitis, severepostoperatively, anterior uveitis, severeallergic conjunctivitis, vernal keratoconjunctivitis,allergic conjunctivitis, vernal keratoconjunctivitis,prevention and suppression of corneal graftprevention and suppression of corneal graft
rejection, episcleritis, scleritisrejection, episcleritis, scleritis Side effects:Side effects: susceptibility to infectionssusceptibility to infections,,
glaucomaglaucoma,, cataractcataract, ptosis, mydriasis, scleral, ptosis, mydriasis, scleralmelting, skin atrophymelting, skin atrophy
-
8/8/2019 Ocular Pharmacology and Toxicology 2
29/55
CorticosteroidsCorticosteroids
Systemic:Systemic:
E.g. prednisolone, cortisoneE.g. prednisolone, cortisone
Uses:Uses: posterior uveitis, optic neuritis, temporalposterior uveitis, optic neuritis, temporalarteritis with anterior ischemic optic neuropathyarteritis with anterior ischemic optic neuropathy
Side effects:Side effects:
Local:Local: posterior subcapsular cataractposterior subcapsular cataract, glaucoma,, glaucoma,central serous retinopathycentral serous retinopathy
Systemic: suppression of pituitarySystemic: suppression of pituitary--adrenal axis,adrenal axis,hyperglycemia, osteoporosis, peptic ulcer, psychosishyperglycemia, osteoporosis, peptic ulcer, psychosis
-
8/8/2019 Ocular Pharmacology and Toxicology 2
30/55
NSAIDNSAID
E.g. ketorolac, diclofenac, flurbiprofenE.g. ketorolac, diclofenac, flurbiprofen
Mechanism:Mechanism: inactivation of cycloinactivation of cyclo--
oxygenaseoxygenase Uses:Uses: postoperatively, mild allergicpostoperatively, mild allergic
conjunctivitis, episcleritis, mild uveitis,conjunctivitis, episcleritis, mild uveitis,
cystoid macular edema, preoperativelycystoid macular edema, preoperativelyto prevent miosis during surgeryto prevent miosis during surgery
Side effects:Side effects: stingingstinging
-
8/8/2019 Ocular Pharmacology and Toxicology 2
31/55
AntiAnti--allergicsallergics
Avoidance of allergens, cold compress, lubricationsAvoidance of allergens, cold compress, lubrications
AntihistaminesAntihistamines (e.g.pheniramine, levocabastine)(e.g.pheniramine, levocabastine)
DecongestantsDecongestants (e.g. naphazoline, phenylepherine,(e.g. naphazoline, phenylepherine,
tetrahydrozaline)tetrahydrozaline) Mast cell stabilizersMast cell stabilizers (e.g. cromolyn, lodoxamide, pemirolast,(e.g. cromolyn, lodoxamide, pemirolast,
nedocromil, olopatadine)nedocromil, olopatadine)
NSAIDNSAID (e.g. ketorolac)(e.g. ketorolac)
SteroidsSteroids (e.g. fluorometholone, remixolone, prednisolone)(e.g. fluorometholone, remixolone, prednisolone)
Drug combinationsDrug combinations
-
8/8/2019 Ocular Pharmacology and Toxicology 2
32/55
AntibioticsAntibiotics
PenicillinsPenicillins
CephalosporinsCephalosporins
SulfonamidesSulfonamides TetracyclinesTetracyclines
ChloramphenicolChloramphenicol
AminoglycosidesAminoglycosides
FluoroquinolonesFluoroquinolones
VancomycinVancomycin
macrolidesmacrolides
-
8/8/2019 Ocular Pharmacology and Toxicology 2
33/55
AntibioticsAntibiotics
UsedUsed topicallytopically in prophylaxisin prophylaxis(pre and postoperatively) and(pre and postoperatively) andtreatment of ocular bacterialtreatment of ocular bacterialinfections.infections.
UsedUsed orallyorally for the treatmentfor the treatmentof preseptal cellulitisof preseptal cellulitise.g. amoxycillin withe.g. amoxycillin withclavulonate, cefaclorclavulonate, cefaclor
UsedUsed intravenouslyintravenously for thefor thetreatment of orbital cellulitistreatment of orbital cellulitise.g. gentamicin, cephalosporin,e.g. gentamicin, cephalosporin,
vancomycin, flagylvancomycin, flagyl Can be injectedCan be injected intravitrallyintravitrally forfor
the treatment ofthe treatment ofendophthalmitisendophthalmitis
-
8/8/2019 Ocular Pharmacology and Toxicology 2
34/55
AntibioticsAntibiotics
TrachomaTrachoma can be treated bycan be treated bytopical and systemictopical and systemictetracycline or erythromycin, ortetracycline or erythromycin, orsystemic azithromycin.systemic azithromycin.
Bacterial keratitisBacterial keratitis (bacterial(bacterialcorneal ulcers) can be treatedcorneal ulcers) can be treatedby topical fortified penicillins,by topical fortified penicillins,cephalosporins,cephalosporins,aminoglycosides, vancomycin,aminoglycosides, vancomycin,or fluoroquinolones.or fluoroquinolones.
Bacterial conjunctivitisBacterial conjunctivitis isisusually self limited but topicalusually self limited but topical
erythromycin, aminoglycosides,erythromycin, aminoglycosides,fluoroquinolones, orfluoroquinolones, orchloramphenicol can be usedchloramphenicol can be used
-
8/8/2019 Ocular Pharmacology and Toxicology 2
35/55
AntifungalsAntifungals
Uses:Uses: fungal keratitis, fungal endophthalmitisfungal keratitis, fungal endophthalmitis
PolyenesPolyenes damage cell membrane of susceptible fungidamage cell membrane of susceptible fungi
e.g. amphotericin B, natamycine.g. amphotericin B, natamycin
side effect: nephrotoxicityside effect: nephrotoxicity
ImidazolesImidazoles increase fungal cell membrane permeabilityincrease fungal cell membrane permeability
e.g. miconazole, ketoconazolee.g. miconazole, ketoconazole
FlucytocineFlucytocine act by inhibiting DNA synthesisact by inhibiting DNA synthesis
-
8/8/2019 Ocular Pharmacology and Toxicology 2
36/55
AntiviralsAntivirals
AcyclovirAcyclovir
interact with viral thymidineinteract with viral thymidinekinase (selective)kinase (selective)
used in herpetic keratitisused in herpetic keratitis TrifluridineTrifluridine
more corneal penetrationmore corneal penetration
can treat herpetic iritiscan treat herpetic iritis
GanciclovirGanciclovir
used intravenously for CMVused intravenously for CMVretinitisretinitis
-
8/8/2019 Ocular Pharmacology and Toxicology 2
37/55
Ocular diagnostic drugsOcular diagnostic drugs
Fluorescein dyeFluorescein dye
Available as drops orAvailable as drops orstripsstrips
Uses:Uses: stain cornealstain cornealabrasions, applanationabrasions, applanationtonometry, detectingtonometry, detectingwound leak, NLDwound leak, NLDobstruction, fluoresceinobstruction, fluorescein
angiographyangiography Caution:Caution:
stains soft contact lensstains soft contact lens
Fluorescein drops canFluorescein drops canbe contaminated bybe contaminated byPseudomonas sp.Pseudomonas sp.
-
8/8/2019 Ocular Pharmacology and Toxicology 2
38/55
Ocular diagnostic drugsOcular diagnostic drugs
Rose bengal stainRose bengal stain
Stains devitalized epitheliumStains devitalized epithelium
Uses:Uses: severe dry eye, herpetic keratitissevere dry eye, herpetic keratitis
-
8/8/2019 Ocular Pharmacology and Toxicology 2
39/55
Local anestheticsLocal anesthetics
topicaltopical E.g. propacaine, tetracaineE.g. propacaine, tetracaine
Uses:Uses: applanation tonometry, goniscopy,applanation tonometry, goniscopy,removal of corneal foreign bodies,removal of corneal foreign bodies,removal of sutures, examination ofremoval of sutures, examination ofpatients who cannot open eyes becausepatients who cannot open eyes because
of painof pain Adverse effects:Adverse effects: toxic to cornealtoxic to corneal
epithelium, allergic reaction rarelyepithelium, allergic reaction rarely
-
8/8/2019 Ocular Pharmacology and Toxicology 2
40/55
Local anestheticsLocal anesthetics
Orbital infiltrationOrbital infiltration
peribulbar or retrobulbarperibulbar or retrobulbar
causecause anesthesiaanesthesia andand akinesiaakinesia forforintraocular surgeryintraocular surgery
e.g. lidocaine, bupivacainee.g. lidocaine, bupivacaine
-
8/8/2019 Ocular Pharmacology and Toxicology 2
41/55
Other ocular preparationsOther ocular preparations
LubricantsLubricants
drops or ointmentsdrops or ointments
Polyvinyl alcohol,Polyvinyl alcohol,cellulose,cellulose,methylcellulosemethylcellulose
Preserved orPreserved or
preservative freepreservative free
-
8/8/2019 Ocular Pharmacology and Toxicology 2
42/55
Ocular toxicologyOcular toxicology
-
8/8/2019 Ocular Pharmacology and Toxicology 2
43/55
Complications of topicalComplications of topical
administrationadministration Mechanical injuryMechanical injury from thefrom the
bottle e.g. corneal abrasionbottle e.g. corneal abrasion
Pigmentation:Pigmentation: epinephrineepinephrine--
adrenochromeadrenochrome Ocular damage:Ocular damage: e.g. topicale.g. topical
anesthetics, benzylkoniumanesthetics, benzylkonium
Hypersensitivity:Hypersensitivity: e.g.e.g.atropine, neomycin,atropine, neomycin,gentamicingentamicin
Systemic effect:Systemic effect: topicaltopicalphenylephrine can increasephenylephrine can increaseBPBP
-
8/8/2019 Ocular Pharmacology and Toxicology 2
44/55
-
8/8/2019 Ocular Pharmacology and Toxicology 2
45/55
DigitalisDigitalis
A cardiac failure drugA cardiac failure drug
CausesCauses chromatopsiachromatopsia (objects appear(objects appearyellow) with overdoseyellow) with overdose
-
8/8/2019 Ocular Pharmacology and Toxicology 2
46/55
ChloroquinesChloroquines
E.g. chloroquine,E.g. chloroquine,hydroxychloroquinehydroxychloroquine
Used in malaria, rheumatoidUsed in malaria, rheumatoid
arthritis, SLEarthritis, SLE Cause vortex keratopathyCause vortex keratopathy
(corneal verticillata) which(corneal verticillata) whichis usually asymptomatic butis usually asymptomatic butcan present with glare andcan present with glare and
photophobiaphotophobia Also causeAlso cause retinopathyretinopathy
(bulls eye maculopathy)(bulls eye maculopathy)
-
8/8/2019 Ocular Pharmacology and Toxicology 2
47/55
ChorpromazineChorpromazine
A psychiatric drugA psychiatric drug
CausesCauses corneal punctatecorneal punctate epithelialepithelialopacitiesopacities,, lens surface opacitieslens surface opacities
Rarely symptomaticRarely symptomatic
Reversible with drug discontinuationReversible with drug discontinuation
-
8/8/2019 Ocular Pharmacology and Toxicology 2
48/55
ThioridazineThioridazine
A psychiatric drugA psychiatric drug
Causes aCauses a pigmentary retinopathypigmentary retinopathy afterafterhigh dosagehigh dosage
-
8/8/2019 Ocular Pharmacology and Toxicology 2
49/55
DiphenylhydantoinDiphenylhydantoin
An epilepsy drugAn epilepsy drug
Causes dosageCauses dosage--related cerebellarrelated cerebellar--vestibular effects:vestibular effects:
HorizontalHorizontal nystagmusnystagmus in lateral gazein lateral gaze
DiplopiaDiplopia,, ophthalmoplegiaophthalmoplegia
Vertigo, ataxiaVertigo, ataxia
Reversible with the discontinuation ofReversible with the discontinuation ofthe drugthe drug
-
8/8/2019 Ocular Pharmacology and Toxicology 2
50/55
TopiramateTopiramate
A drug for epilepsyA drug for epilepsy
CausesCauses acute angleacute angle--closure glaucomaclosure glaucoma(acute eye pain, redness, blurred(acute eye pain, redness, blurredvision, haloes).vision, haloes).
Treatment of this type of acute angleTreatment of this type of acute angle--
closure glaucoma is byclosure glaucoma is by cycloplegia andcycloplegia andtopical steroidstopical steroids (rather than(rather thaniridectomy) with the discontinuation ofiridectomy) with the discontinuation of
the drugthe drug
-
8/8/2019 Ocular Pharmacology and Toxicology 2
51/55
EthambutolEthambutol
An antiAn anti--TB drugTB drug
Causes a doseCauses a dose--relatedrelated opticopticneuropathyneuropathy
Usually reversible but occasionallyUsually reversible but occasionallypermanent visual damage might occurpermanent visual damage might occur
-
8/8/2019 Ocular Pharmacology and Toxicology 2
52/55
Agents that Can CauseAgents that Can Cause
Toxic Optic NeuropathyToxic Optic Neuropathy MethanolMethanol Ethylene glycol (antifreeze)Ethylene glycol (antifreeze) ChloramphenicolChloramphenicol IsoniazidIsoniazid EthambutolEthambutol DigitalisDigitalis ChloroquineChloroquine StreptomycinStreptomycin AmiodaroneAmiodarone QuinineQuinine
Vincristine and methotrexateVincristine and methotrexate(chemotherapy medicines)(chemotherapy medicines) SulfonamidesSulfonamides Melatonin with ZoloftMelatonin with Zoloft
(sertraline, Pfizer) in a(sertraline, Pfizer) in a
highhigh--protein dietprotein diet Carbon monoxideCarbon monoxide LeadLead MercuryMercury Thallium (alopecia, skin rash,Thallium (alopecia, skin rash,
severe vision loss)severe vision loss) Malnutrition with vitamin BMalnutrition with vitamin B--11
deficiencydeficiency Pernicious anemia (vitamin BPernicious anemia (vitamin B--
12 malabsorption12 malabsorption phenomenon)phenomenon) Radiation (unshieldedRadiation (unshielded
exposure to >3,000 rads).exposure to >3,000 rads).
-
8/8/2019 Ocular Pharmacology and Toxicology 2
53/55
HMGHMG--CoA reductaseCoA reductase
inhibitors (statins)inhibitors (statins) Cholesterol lowering agentsCholesterol lowering agents
E.g. pravastatin, lovastatin, simvastatin,E.g. pravastatin, lovastatin, simvastatin,
fluvastatin, atorvastatin, rosuvastatinfluvastatin, atorvastatin, rosuvastatin Can causeCan cause cataractcataractin high dosages speciallyin high dosages specially
if used with erythromycinif used with erythromycin
-
8/8/2019 Ocular Pharmacology and Toxicology 2
54/55
-
8/8/2019 Ocular Pharmacology and Toxicology 2
55/55
Thank youThank you
Any question?