Local anaesthetics.pdf. PHARMACOLOGY D-PH-II

LOCAL ANAESTHETICS.
PHARMACOLOGY
DIPLOMA II YR

1. LOCAL ANAESTHETICS
(D-PH-II)
ER.20
MISS.Rubis. khan
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3. LOCAL ANAESTHETICS
Localanesthetics(LAs)aredrugsthatblockthesensationofpaininthe
regionwheretheyareadministered.LAsactbyreversiblyblockingthe
sodiumchannelsofnervefibers,therebyinhibitingtheconductionof
nerveimpulses.
Approximately4-6hourseffect.
Thesecompoundsproducelossofsensationspeciallypainsensationfrom
localisedarea.
Lossofmotorfunctionandsensationoftouchandpressurefollow,
dependingonthedurationofactionanddoseoftheLAused.
Theybindprimarilytosodiumchannelsbutalsotopotassiumandcalcium
channels,andG-protein-coupledreceptors.
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4. LOCAL ANESTHESIA IS USED
WHEN ?
Surgery is minor and does not require
general or regional anesthesia
The procedure can be done quickly and
the patient does not need to stay
overnight
The operation does not need the muscles
to be relaxed or for the patient to
be unconscious
Examples include dental surgery, the
removal of A verruca, A mole, or A
cataract and biopsies.
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5. IDEAL PROPERTIES OF LOCAL ANAESTHETICS
1.It should be soluble in both water and lipids.
2.It should not decompose on standing.
3.Non-irritating to tissues and not causing any permanent damage.
4.Low systemic toxicity.
5.It should be non-antigenic.
6.Effective whether injected into the tissue or applied locally to skin or
mucous membranes.
7.Rapid onset of anaesthesiaand short duration of action.
8.It should not cause any permanent damage to the nerves.
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6. CLASSIFICATION
Amide Type
Longer Acting: Bupivacaine, levo-Bupivacaine, Etidocaine, Ropivacaine,
Dibucaine
Intermediate acting: Lidocaine(Xylocaine), Mepivacaine, Prilocaine
Ester Type
Longer Acting: Tetracaine(Amethocaine)
Intermediate Acting: Cocaine
Short Acting: Procaine, Chloroprocaine, Benzocaine, Betambenm
ProparacaineMiscellaneous: Pramoxine(Pramocaine),
Dyclonine, Oxetacaine.
Miscellaneous: Pramoxine(Pramocaine), Dyclonine, Oxetacaine
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7. MECHANISM OF ACTION
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Local anaesthetics

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9. PHARMACOLOGICAL ACTION
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10. COCAIN
Dose-5 to 10% solution ( topical application)
Use-as ocular anesthetic,
AE-mydriasis, dryness, damage to cornea
PROCAIN
Dose-1-2% solution (injection)
Use-block nerve, spinal anesthetics, analgesic
AE-convulsion, tachycardia, hypertension
LIDOCAIN(XYLOCAIN)
Dose-4% solution topical, 5% ointment, 1%-2% injection,5% solution for spinal
anaesthesia.
Use-topically for piles and fissure, nerve block, skin edema
AE-drowsiness, altered taste, tinnitus.
Contraindication-inflamed skin, skin infection, sever anemia, heart disease,
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11. BUPIVACAIN HCL
Widely used amide local anesthetics. It is produce prolonged anesthesia.
Dose-2.5mg/ml(0.25%), 5mg/ml(0.5%) injection
Use-Helps in peripheral and sympathetic nerve block, post operative pain relief.
AE-convulsion, tachycardia, hypertension
Contraindication-Inflamed skin, skin infection, sever anemia, heart disease,
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