ideal requirements and composition of local anaesthesia

8/8/2019 Ideal Requirements and Composition of Local Anaesthesia

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IDEAL REQUIREMENTS

AND COMPOSITION OF

LOCAL ANAESTHESIA

Dr.Shabana Shaikh

B.D.S.Lecturer, Dept of Oral & Maxillofacial

Surgery,

M.M.N.G.H Institute of Dental Sciences,

Belgaum.


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DEFINITIONDEFINITION

LOCAL ANAESTHESIALOCAL ANAESTHESIA

Local anaesthesia is the loss of sensation in aLocal anaesthesia is the loss of sensation in acircumscribed area of the body caused by acircumscribed area of the body caused by a

depression of excitation in nerve endings or andepression of excitation in nerve endings or an

inhibition of the conduction process in peripheralinhibition of the conduction process in peripheral

nerves.nerves.


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LOCAL ANAESTHETICSLOCAL ANAESTHETICS

Local anaesthetics are drugs that have little orLocal anaesthetics are drugs that have little or

no irritating effects when injected into the tissuesno irritating effects when injected into the tissues

and that will temporarily interrupt conductionand that will temporarily interrupt conduction

when absorbed into the nerves.when absorbed into the nerves.

eg. : Lignocaine, Procaine, Xylocaineeg. : Lignocaine, Procaine, Xylocaine


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IDEAL REQUIREMENTS OFIDEAL REQUIREMENTS OF


The action must be reversible.The action must be reversible.

NonNon--irritating to the tissues.irritating to the tissues.

No secondary local reactions.No secondary local reactions.

Low degree of systemic toxicity.Low degree of systemic toxicity.

Rapid onset & sufficient duration of action.Rapid onset & sufficient duration of action.

Potency sufficient to render complete anesthesia.Potency sufficient to render complete anesthesia.


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IDEAL REQUIREMENTS OFIDEAL REQUIREMENTS OF

LOCAL ANAESTHESIALOCAL ANAESTHESIA (cont)(cont)

Potency sufficient to render complete anesthesia.Potency sufficient to render complete anesthesia.

Sufficient penetrating properties.Sufficient penetrating properties. NonNon--allergenic.allergenic.

Stable in solution.Stable in solution.

Undergo biotransformation readily in the body.Undergo biotransformation readily in the body.

Sterile.Sterile.


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CLASSIFICATION OFCLASSIFICATION OF


( I ) BASED ON CHEMICAL COMPOSITION( I ) BASED ON CHEMICAL COMPOSITION

( A ) ESTER GROUP( A ) ESTER GROUP

( B ) NON ESTER GROUP( B ) NON ESTER GROUP


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ESTER GROUPESTER GROUP

A.Benzoic acid esters :A.Benzoic acid esters :

1.Cocaine(topical only).1.Cocaine(topical only).

2.Benzocaine(topical).2.Benzocaine(topical).B.ParaB.Para--aminobenzoic acid esters :aminobenzoic acid esters :

1. Procaine.1. Procaine.

2. Tetracaine.2. Tetracaine.3. Propoxycaine.3. Propoxycaine.


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NON ESTER GROUPNON ESTER GROUP

AMIDESAMIDES

*Atricaine*Atricaine

*Lignocaine*Lignocaine*Bupivacaine*Bupivacaine

*Prilocaine*Prilocaine

QUINOLONESQUINOLONES*Centbucridine*Centbucridine


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Based on duration of actionBased on duration of action

1) Short duration (apprx.30 minutes)1) Short duration (apprx.30 minutes)

Lignocaine HCl 2%Lignocaine HCl 2%Mepivacaine HCl 2%Mepivacaine HCl 2%

Prilocaine HCl 4%Prilocaine HCl 4%


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Intermediate duration (apprx.60 minutes)Intermediate duration (apprx.60 minutes)

*Lidocaine HCL 2% + Epinephrine 1:100000*Lidocaine HCL 2% + Epinephrine 1:100000

*Atricaine HCl 4% + Epinephrine 1:200000*Atricaine HCl 4% + Epinephrine 1:200000

*Prilocaine HCl 4% + Epinephrine 1:200000*Prilocaine HCl 4% + Epinephrine 1:200000


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Long duration (apprx. 90+minutes)Long duration (apprx. 90+minutes)

Bupivacaine HCl 0.5%+EpinephrineBupivacaine HCl 0.5%+Epinephrine

1:2000001:200000


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(III ) BASED ON BIOLOGICAL(III ) BASED ON BIOLOGICAL

SITE AND MODE OF ACTIONSITE AND MODE OF ACTIONClass AClass A

Acting at receptor site on external surface of nerveActing at receptor site on external surface of nervemembranemembrane

eg. : Biotoxinseg. : Biotoxins

Class BClass BActing at receptor site on internal surface of nerveActing at receptor site on internal surface of nerve

membranemembraneeg. : Scorpion venom,Quaternary ammonium analogues ofeg. : Scorpion venom,Quaternary ammonium analogues oflidocainelidocaine


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(III) BASED ON BIOLOGICAL SITE(III) BASED ON BIOLOGICAL SITE

AND MODE OF ACTIONAND MODE OF ACTIONClass CClass C

Acting by a receptorActing by a receptor--independent physiochemicalindependent physiochemical

mechanismmechanismeg. : Benzocaineeg. : Benzocaine

Class DClass D

Acting by combination of receptor and receptorActing by combination of receptor and receptorindependent mechanismsindependent mechanisms

eg. : Articaine, Lidocaine, Prilocaineeg. : Articaine, Lidocaine, Prilocaine


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LOCAL ANAESTHETICSLOCAL ANAESTHETICS

May be an amide or an ester.May be an amide or an ester.


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VASOCONSTRICTORVASOCONSTRICTOR

Epinephrine is used as a vasoconstrictorEpinephrine is used as a vasoconstrictor

-- Causes vasoconstriction and preventsCauses vasoconstriction and prevents

rapid absorption.rapid absorption.-- It produces desired effect at lowerIt produces desired effect at lower

dose of L.A.dose of L.A.

-- It reduces systemic toxicity.It reduces systemic toxicity.

-- It also causes hemostasis.It also causes hemostasis.


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ANTIOXIDANTANTIOXIDANT

Sodium metabisulphiteSodium metabisulphite

It delays rapid oxidation of vasoconstrictorIt delays rapid oxidation of vasoconstrictorand prolongs the shelf life of the solutionand prolongs the shelf life of the solution


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PRESERVATIVEPRESERVATIVE

Methyl parabenMethyl paraben

FUNGICIDEFUNGICIDE

ThymolThymol


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SALTSALT

Bicarbonate is added to make the solutionBicarbonate is added to make the solution

isotonicisotonic


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VEHICLEVEHICLE

Distilled water or ringer lactate solutionDistilled water or ringer lactate solution

Helps to dissolve the content of L.A toHelps to dissolve the content of L.A tomake it injectible.make it injectible.

Also reduces the concentration of the drugAlso reduces the concentration of the drug

which provides additional volume forwhich provides additional volume forinjection.injection.


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EACH ML CONTAINSEACH ML CONTAINS

Lignocaine HCl 21.33Lignocaine HCl 21.33

Adrenaline Bititrate 0.0225 mgAdrenaline Bititrate 0.0225 mg

Sodium Chloride Sodium Chloride Sodium Metabisulphite 0.5 mgSodium Metabisulphite 0.5 mg

Methyl Paraben Methyl Paraben

Water for injection q.sWater for injection q.s


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ideal requirements and composition of local anaesthesia

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