Upload
drmohmed-mostafa
View
226
Download
0
Embed Size (px)
Citation preview
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
1/55
CLASSIFICATION OF LOCAL
ANESTHETICS
ByPETER Y. BONILLA, B.S.Med.Tech. (RMT).,D.M.D.,M.A.,M.S.
Ass. Professor
Endodontics-Periodontics Section
College of Dentistry
Centro Escolar University
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
2/55
LOCAL ANESTHETICS
are drugs that have little or no
irritating effects when injected into the
tissues and that will temporarilyinterrupt conduction when absorbed
into the nerve
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
3/55
Local anesthetics
A blockade of all afferent nervetransmission produces anesthesia or a lackof all sensation
Blockade of those fibers transmitting painsensation only results in regional analgesia
Interruption of efferent fibers results inmotor paralysis and an inhibition ofautonomically innervated structures
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
4/55
PROPERTIES OF AN IDEAL
LOCAL ANESTHETIC
1. Its action should be reversible
2. It must be nonirritating to the tissues and
produce no secondary local reaction3. It should have a low degree of systemic
toxicity
4. It should have a rapid onset and be of
sufficient duration to be advantageous
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
5/55
5. It should have a potency sufficient to givecomplete anesthesia without the use ofharmful concentrated solutions
6. It should have sufficient penetratingproperties to be effective as a topicalanesthetic
7. It should be relatively free from producingallergic reactions
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
6/55
8. It should be stable in solution and undergo
biotransformation readily within the body
9. It should be either sterile or capable ofbeing sterilized by heat without deterioration.
*No local anesthetic in use today fulfills toperfection all these requirements
*Systemic toxicity is often considered to be indirect proportion with anesthetic potency
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
7/55
Chemical Groups of LOCAL
ANESTHETICS commonly used indentistry:
I. Ester groupA. Benzoic acid esters
1. Cocaine (topical only) naturally
occurring2. Benzocaine (topical only)
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
8/55
Chemical Groups of LOCAL ANESTHETICScommonly used in dentistry:
B. Para-aminobenzoic acid esters
1. Procaine (Novocaine)
2. Tetracaine (Pontocaine)extremelystrong local anesthetic for surfaceanesthesia; no real injection use
3. Propoxycaine (Ravocaine)4. 2-Chloroprocaine (Nesacaine) (notmarketed in an dental cartridge)
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
9/55
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
10/55
Excretion and Absorption of LocalAnesthetics
1. Esters: Hydrolyzed by plasmaesterase and by products
excreted in urine. Note that oneby product is PABA (para-aminobenzoic acid)
2. Amides: Metabolized in liver bymicrosomal enzymes and only 1020% is excreted unchanged
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
11/55
Cocaine
From the leaves of a plant calledErthroxylon coca; 1855 French chemistF. Gaedcke
Albert Niemann isolated the alkaloid inits pure formnamed it cocaine1884, Carl Koller, encouraged bySigmund Freud, discovered that it iseffective surface anesthesia of thecornea
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
12/55
Cocaine
William Steward Halsted in Americaused the solution to produce anesthesiain the inferior dental nerve; victim ofthe drugs addictiveproperties
First record of use in Britain, JADA1886, William Alfred Hunt describeduse in infiltration
1901, E. Mayer suggested addition ofadrenalinepromote vasoconstriction,prolong duration, and intensify depth ofanesthesia
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
13/55
Cocaine
Rarely used these days due to problemsof misuse
Methyl 3-hydroxy-1H-tropan-2-carboxylate ester benzoate (chemicalname)
Unique among local anesthetic agents inthat it produces vasoconstriction
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
14/55
CocainePreparation:
Topical preparation as a 4 - 10% solutionRecommended uses in Dentistry:
Should not be considered as a normal part
of dental local anesthetic armamentariumdue to its obvious disadvantagepotentialfor abuse
Occasionally used topically intranasallyduring apical surgery on maxillary incisorteeth when the nasal floor is in close
proximity
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
15/55
Benzocaine
Most commonly used ester localanesthetic
Ethyl-p-aminobenzoate (chemical name)
Dosage
Due to its extremely poor solubility in
water and poor absorption, toxicreactions to benzocaine are almostunknown
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
16/55
Benzocaine
Preparation: Extremely poor water solubility not
suitable for injection; available only intopical preparations
Available in number of concentrationsup to 20% and in combination with otheragents
Different flavors have been added tobenzocaine gel to make themparticularly popular with children
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
17/55
Benzocaine
Recommended uses in Dentistry:
Topical application prior to aninfiltration means of reducing pain
Incorporated into proprietarymedications for application to painfulintraoral lesions ulcers
Sole source of anesthesia forsuperficial soft tissue manipulation
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
18/55
Procaine
Produced synthetically procainehydrochloride by two Swedish chemists,
Alfred Einhorn & E. UhlfelderTested clinically by Henrich Braun andmarketed as Novocaine (proprietary
name)Archetypal dental local anesthetic priorto the introduction of lignocaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
19/55
Procaine
Use has declined for a number ofreasons: susceptible persons maybecome sensitized to this substance;can cause dermatitis, urticaria and eveneodema of the glottis
Not as potent as cocaine, but it is verymuch less toxic
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
20/55
Procaine
Preparation:Rarely used as sole anesthetic inDentistry todayNo longer available in cartridges in someparts of the world and must be drawn upin ampuleNormal presentation is 2% solution,
however 1:80,000 adrenaline may beaddedNot available as a topical agent
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
21/55
Procaine
Recommended uses in DentistryOnly indication for use as a localanesthetic is in patients with proven
allergy to the amide groupUseful in intravenous sedation relevantto dental practiceRecognized regimen to treatarteriospasm when it is administeredintra-arterially excellent vasodilatoryproperties
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
22/55
Procaine
Onset and duration of action
Onset of action: 10 minutes (pulpal)Duration of action: plain solution,extremely short-lived pulpal anesthesia
of approximately 5 minutessolution with adrenaline, pulpalanesthesia of 30 minutes
Dosage
Maximum dose is 6 mg/kg with ceiling of
400 mg
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
23/55
TetracainePara-butylaminobenzoyl-2-dimethylaminoethanol hydrochloride(chemical name)Proprietary name: Pontocaine
10x as potent and 10x as toxic asprocaineChemically it is closely related to
procaine but pharmacologically it iscloser to cocainePotent topical agent, does not possessvasoconstricting properties
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
24/55
Tetracaine
Popular for the production of spinalanesthesia
No longer available in cartridges for usein dentistryLimited almost exclusively to topicalapplication
Rapidly absorbed into systemiccirculationtoxic effects, not sprayedon mucous membrane
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
25/55
Tetracaine
Preparation
0.15%, 1% and 2% topical solutions
Plain tetracaine hydrochloride Tetracaine hydrochloride with
1:100,000 vasodilator
Dosage Maximum of 20 mg (1 ml of 2% solution)
be applied at one time
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
26/55
Tetracaine
Duration of action
When injected, plain 0.15% solution willproduce 30 45 minutes of analgesia
Same concentration with 1:100,000
epinephrine will produce 75 120minutes of analgesia
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
27/55
Tetracaine
Recommended use in Dentistry
Although efective when given byinjection, it is not used in this mannerdue to its toxicity.
It is available in topical preparationsboth on its own and in combination withother anesthetic agents such aslignocaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
28/55
Propoxycaine (Ravocaine)
2-diethylaminoethyl 4-amino-2-propoxybenzoate is its chemical nameEqual in potency and toxicity totetracaine
Preparation
Not used alone in dentistry, combinedwith procaine, in a procaine 2%,propoxycaine 0.4% solution with either1:20,000 levondefrin or 1: 30,000levarterenol as vasoconstrictor
P i
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
29/55
Propoxycaine
Duration of action
Combination of procaine and propoxycainegives rapid and profound anesthesia witha pulpal analgesia of about 1 1.5 hours
and soft tissue duration of 2 3 hoursDosage
Suggested maximum dose is 6.6 mgkg (3
mg/lb) Maximum total anesthetic (procaine plus
propoxycaine) dosage should not exceed
400 mg
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
30/55
2-Chloroprocaine
Proprietary name: NesacaineBeta-diethylaminoethyl-2-chloro-4-aminobenzoate (chemical name)
Differs from other local anesthetic ofthe ester group in having a chlorideatom substituted in the benzene ring
2x as potent but less toxic thanprocaine hydrolyzed 4x-5x faster thanprocaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
31/55
2-Chloroprocaine
Preparation
Not available in dental cartridge,multiple dose vial via disposable 3 to 5cc syringe with a 25-gauge Leur-Lokneedle
Available in 1.2% or 3% concentrations,must be used with a vasoconstrictor dueto its shortness of duration
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
32/55
2-Chloroprocaine
Onset and duration of action
Extremely rapid onset with a
satisfactory short-acting anesthetic(low toxicity) thus advantageous in usefor children who may inadvertentlytraumatize the lip, tongue or cheek withlonger-acting agents
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
33/55
Lignocaine
Most commonly used dental anestheticSynthetized in 1943, has been in clinicaluse since 1948Proprietary names: Xylocaine, Lignospan,
Lignostab, & Lidocaine (North America)Chemical name: 2-diethylamino-2,6-acetoxylidide.
2x potency than procaineMore profound anesthesia and longduration (spreads more widely throughtissues)
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
34/55
Lignocaine
Preparations:
Dental cartridges plain 2%solution and a 2% solution with1:80,000 or 1:100,000 adrenaline
Topical 4% and 10% spray, 2%gels, and 5% ointment
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
35/55
Lignocaine
Recommended uses in Dentistry:2% with 1:80,000 adrenaline--ideal forinfiltration, intraosseous,
intraligamentary, and regional blockanesthesia for majority of patientsContraindicated in those allergic to
amides and in individuals whereincreased adrenaline levels may behazardous
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
36/55
Lignocaine
Recommended uses in Dentistry:Plain solution is not very effective inobtaining pulpal anesthesia
Use for soft tissue procedures is verylimitedpoor hemorrhage controlNevertheless, effective topicalanesthetic for non-keratinized tissue:
reflected mucosa & as a symptomatictreatment for painful mucosal lesionssuch as ulcers
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
37/55
LignocaineOnset and duration of action
Short onset of action, pulpal anesthesiaobtained in 2-3 minutes ff. infiltration
Plain solution is classified as short-actingagent, will provide pulpal anesthesia for 10minutes; 1-1 hours soft tissue anesthesia
Adrenaline containing solution is
intermediate in duration providing 45-60minutes (1-1 hours) of pulpal anesthesia;3-4 hours soft tissues anesthesia
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
38/55
PrilocaineToluidine derivative; related both
chemically and pharmacologically to bothlignocaine and mepivacaine
Proprietary name: Citanest
2-propylamino-o-propionotoluidine(chemical name)
As potent as lignocaine but is less toxic
Metabolized more rapidly thanlignocaine
Does not produce topical anesthesia
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
39/55
PrilocainePreparations
Plain solution is 4%Vasoconstrictor-containing version is3% with 0.03 IU/ml felypressin (UK)
In other parts of the world prilocaine isavailable with adrenalineTopical anesthetic agent available
combination prilocaine & lignocaineEMLA (Eutectic Mixture of LocalAnesthetics)
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
40/55
Prilocaine
Recommended use in Dentistry3% with 0.03 IU felypressin is the alternative tolignocaine with adrenaline when a vasoconstrictor-containing solution is requiredEffective when administered as an infiltration or
regional block anestheticNot as effective as lignocaine duringintraligamentary techniques4% plain prilocaine more effective than 2%
lignocaine when a vasoconstrictor-free solutionmust be employedEMLA useful prior to venepuncture in childrenand during dental sedation; oral application notrecommended by manufacturers
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
41/55
Prilocaine
ContraindicationsShould not be administered to infants,patients with methaemoglobineamia, kidney
disease, hypoxia, anemia, liver disease orheart failure, or any other condition in whichproblems with oxygenation could be critical,such as pregnancy
Should not be used in patients who have ahistory of either sensitivity to an amide-typelocal anesthetic agent or paraben allergy
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
42/55
Prilocaine
Onset and duration of actionSlower onset of action than lignocaine:pulpal anesthesia 4 minutes
4% prilocaine short-acting agent withpulpal anesthesia lasting around 10minutes
3% with 0.03 IU felypressin providesduration of anesthesia similar to thatafforded by lignocaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
43/55
Mepivacaine
The least vasodilatory of the amidelocal anesthetic
Proprietary name: Scandonest (UK),Carbocaine PharmaceuticalManufacturing Co.1-methyl-2,6-pipecoloxylidide (chemicalname)
Mepivacaine without adrenaline has a 5-year shelf-life, irrespective of theconditions of storage
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
44/55
Mepivacaine
Preparations
3% plain solution
2% solution with 1:80,000adrenaline
Not available in a topical
preparation
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
45/55
Mepivacaine
Recommended use in Dentistry:Prime indication is for the use is whenvasoconstrictor-free solution must beemployed as 3% mepivacaine is moreeffective than plain lignocaine orprilocaine solutionsSolution with adrenaline has identical
indications for use as lignocaine withadrenaline although it has a shorterduration of action
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
46/55
Mepivacaine
Onset and duration of actionRapid onset of action: (pulpal) 2 minutes
Duration of action:(pulpal) plain solution30 minuteswith adrenaline provides anesthesia
of similar depth as lignocaine but ofslightly shorter duration
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
47/55
Dosages
Anestheticsolution
Max.dose
(mg/kg)[absolute
ceiling(mg)]
Max. doseof 1.8 ml
cartridgesin an adultof 70 kg
Max. doseof 1.8 ml
cartridges ina 5-year-oldchild of 20kg
Max. doseof 2.2 ml
cartridgesin an adultof 70 kg
Max. doseof 2.2 ml
cartridges ina 5-year-oldchild of 20kg
2% lignocaine 4.4 [300] 8.3 2.4 6.8 2
2% mepivacaine 4.4 [300] 8.3 2.4 6.8 2
3% mepivacaine 4.4 [300] 5.6 1.6 4.5 1.3
3% prilocaine 6.0 [400] 7.4 2.2 6 1.8
4% prilocaine 6.0 [600] 5.5 1.7 4.5 1.4
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
48/55
Bupivacaine
Developed from mepivacaine and is thuschemically related to lignocaineDiffers from mepivacaine in that amethyl group in the piperidine ring has
been replaced by a butyl groupProprietary name: Marcaine,Sensorcaine
1-butyl-2,6-pipecoloxylidide (chemicalname)4x as potent as lignocaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
49/55
Bupivacaine
Preparations:Has recently been available to thedental profession in conventional 1.8 mlcartridgesSupplied in 10,30, & 50 ml vialscontaining 0.25%, 0.375%, 0.5%, 0.75%
solutions available with or without1:200,000 adrenaline
B i i
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
50/55
BupivacaineRecommended uses in Dentistry
Few indications in routine restorativedentistryMain uses are in oral surgeryregional
block, long lasting anesthesiaUseful for post-operative pain controlfollowing procedures such as the
surgical removal of impacted thirdmolarsShort-term temporary relief of acutelypainful conditionstrigeminal neuralgia
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
51/55
Bupivacaine
Onset and duration of action:Onset of action: longer than lignocaine,may take more than 5 minutes pulpal
anesthesiaDuration of action: longer 1.5 2 hourspulpal anesthesia
When used as a regional block, softtissue anesthesia of 6 8 hours ispossible
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
52/55
Bupivacaine
Dosage Total doses in the healthy adult should
not exceed 2.0 mg/kg (0.9 mg/lb), not
to exceed 225 mg with epinephrine1:200,000 and 175 mg withoutvasoconstrictor.
These total doses may be repeated upto once every 3 hours not to exceed400 mg in 24 hours
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
53/55
Etidocaine
Amide derivative that is structurallysimilar to lidocaine
4x as potent as lidocaine, with a twofoldincrease in the duration of action, twiceas toxic
Proprietary name: Duranest
2-ethylpropylethylbutyroxylidide(chemical name)
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
54/55
Etidocaine
Preparations:Dental local anesthetic cartridges as1.5% solution with 1:200,000 adrenaline
Onset and duration of action
Onset of action: 2 3 minutes pulpalDuration of action: long-actinganesthetic similar to bupivacaine
7/29/2019 Lecture05c.(Note;) Classification of Oral Anesthesia
55/55
Etidocaine
Recommended use in Dentistry:Main indications for use are similar tothose mentioned for bupivacaine as a
regional block anestheticWhen used in infiltration techniques forsurgical procedures 1.5% etidocaine
with 1:200,000 adrenaline is not aseffective as 2% lignocaine with 1:80,000adrenaline