Lecture05c.(Note;) Classification of Oral Anesthesia

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


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


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


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


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


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


7/55

Chemical Groups of LOCAL

ANESTHETICS commonly used indentistry:

I. Ester groupA. Benzoic acid esters

1. Cocaine (topical only) naturally

occurring2. Benzocaine (topical only)


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)


9/55


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


32/55

2-Chloroprocaine


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


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)


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


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


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


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


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


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)


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


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


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


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


44/55

Mepivacaine

Preparations

3% plain solution

2% solution with 1:80,000adrenaline

Not available in a topical

preparation


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


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


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


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


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


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


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


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


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)


54/55

Etidocaine

Preparations:Dental local anesthetic cartridges as1.5% solution with 1:200,000 adrenaline


Onset of action: 2 3 minutes pulpalDuration of action: long-actinganesthetic similar to bupivacaine


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

Date post:	04-Apr-2018
Category:	Documents
Upload:	drmohmed-mostafa
View:	226 times
Download:	0 times

Lecture05c.(Note;) Classification of Oral Anesthesia

Documents