aga umar tariq chandrigam

1. LOCAL ANAESTHETICS
LECTURER: UMAR TARIQ
MSC ANAESTHESIA/OTT

2. • First local anaesthetic used was
cocaine by Carl Koller for
anaesthetizing cornea.

3. CLASSIFICATION
Local anaesthetics are classified on the basis of
chemical structure and on the duration of
action.
BASED ON CHEMICAL STRUCTURE
chemically local anaesthetics consists of a
benzene ring separated from tertiary amide
either by ester or amide linkage. Based on this
intermediate chain these are classified as
aminoesters and aminoamides.

4. BASED ON DURATION OF ACTION
AND POTENCY
SHORT DURATION LOW POTENCY
Chloroprocaine(shortest duration)
Procaine
INTERMEDIATE DURATION, INTERMEDIATE
POTENCY
Lignocaine
Mepivacaine
Prilocaine
cocaine

5. LONG DURATION, HIGH POTENCY
• Bupivacaine.
• Levo bupivacaine.
• Tetracaine
• Etidocaine
• Dibucaine(longest duration).
• Ropivacaine
OTHERS
Methoxyflurane-has local anaesthetic properties.

6. CLASSIFICATION OF LOCAL
ANAESTHETICS
AMINOESTERS AMINOAMIDES
Procaine lignocaine
Chloroprocaine Mepivicaine
Tetracaine Prilocaine
Benzocaine Bupivacaine
Cocaine Etidocaine
Ropivicaine
•Esters are metabolised by
pseudocholinesterase(except cocaine
which is metabolised in liver)
•Amides are primarily metabolised in liver.
•Low incidence of allergy reaction
•High incidence of allergy which is •Solutions are stable (not destroyed even

7. MECHANISM OF ACTION
• Local anaesthetics reversibly bind the
intracellular(axoplasmic , cytoplasmic) portion
of voltage –gated sodium channels and stop
nerve conduction.
• At high concentration potassium channels can
also be blocked.

8. AMIDES
1. LIGNOCAINE(XYLOCAINE, LIDNOCAINE)
it is the most commonly used local anaesthetic
• First synthesized by Lofgren and first used by
Gordh.
• Solution is very stable, not even decomposed
by boiling.
• Contains preservative methyl paraben.
• pKa =7.8

9. CONCENTRATION USED
• Surface (topical) analgesia : 4% and 10%
• Nerve blocks : 1% and 2%
• Urethral procedures(as jelly) : 2%
• Spinal :0. 5%(heavy)
• Epidural : 1-2%
• Intravenous regional analgesia : 0.5%
(bier`s block)
• Inflitration block : 1-2%

10. METABOLISM
• Metabolised in liver , excreted by
kidneys
• Half life is 1.6 hours.

11. DURATION OF EFFECT
• Without adrenaline : 45 to 60 minutes
• With adrenaline : 2-3 hours
DOSE :
Without adrenaline :4.5 mg/kg(max 300 mg)
With adrenaline :7mg/kg(max 500 mg)

12. • Systemic toxicity is much less than bupivicaine.
CNS involvement occurs at much lesser dose than
CVS involvement.
• Lignocaine releases calcium from sacro-plasmic
reticulum so should not be used in patients with
history of malignant hyperthermia.
• Can cause cauda equina syndrome after continuous
spinal.

13. OTHER USES
• Used for treating ventricular tachycardia.
Preservative free lignocaine (xylocard 2%) is
used intravenously in dose of 2 mg /kg.
• Intravenous xylocard is used to blunting
cardiovascular response to laryngoscopy and
intubation.

14. MEPIVACAINE
• Mepivacaine is synthetized by Dhuner, and
was first used clinically by Ekenstam in
1956.
• It is a good local analgesic drug.
• Pharmacology is similar to lignocaine
except duration of action slight longer than
lignocaine.
• It causes vasoconstriction very readily.
• Mepivacaine has antiarrhythmic properties

15. Duration of effect
•The onset of action is
usually rapid
•Its duration of action ranges
from 2-3 hours

16. Concentration used
• Mepivacaine is used in all type of blocks.
• Concentration of solution depends upon the
type of block.
• Infiltration analgesia : 0.5-1 %
• Nerve block : 2-3 %
• Spinal : 4% (heavy)
• Caudal & epidural : 1.5-2 %
• It is not effective in topical anaesthesia.

17. SIDE EFFECTS
• Side effects are usually mild.
• Mild tachycardia and hypotension.
• Passed through the placenta barrier
to fetal circulation and may cause
harmful effect on the baby.

18. PRILOCAINE
• Prilocaine is a local analgesic agent
chemically related to lignocaine.
• Prepared by Lofgren and Jegner
• It was first used clinically by Gordh in
1959.
• More potent and less toxic than
lignocaine

19. Metabolism
•Prilocaine is well
absorbed in bloodstream
and metabolised in both
liver and kidneys rapidly

20. Duration of action
• Duration of action ranges from 2.5 to 3
hours in nerve blocks, caudal, spinal
and epidural analgesia
DOSE
• The maximum dose with adrenaline is
600 mg
• Without adrenaline : 400 mg

21. Concentration used
• Infiltration : 0.5 %
• For extremity blocks : 2-3 %
• Caudal % epidural : 3-4 %
• Topical : 4 %
• Bier`s block : 0.5 %

22. Side effects
In excessive overdose toxic symptoms may
occur:
• Cardiovascular collapse
• Coma
• Death
Procaine should not be used in during
labour as fetal haemoglobin is more
sensitive to prilocaine than the adult

23. METHEMOGLOBINEMIA:
• Occurs at high dose(> 6mg/kg)
and this is because of the
accumulation of its metabolite
orthotoludine which can convert
haemoglobin to methaemoglobin.

24. BUPIVACAINE/sensoricaine,
marcain e
• Commonly used drug .
• 4 times more potent than lignocaine and
mepivicaine.
• Available in 0.25% and 5 % solution & solution is
very stable.
• It is highly toxic on the heart in overdose so it
should not be used in beir`s block
• Metabolised in liver
• Elimination half life is 3.5 hrs

25. • The very unique property of bupivacaine which
make it local anaesthetic of choice for post op pain
relief and painless labour is it wide sensory and
motor blockade.
• The drug crosses placenta barrier only a limited
extent and its effect on the baby is usually minimal.
• It is not used in topical anaesthesia.
• Injectable solution is 0.25% ,5 % , 0.75 %.
• Bupivicaine has no severe interactions with other
drugs
• Long acting local anaesthetic

26. DURATION OF EFFECT
• Without adrenaline : 2-3 hours
• With adrenaline : 3-5 hours
Addition of adrenaline has no effect on motor
blockade, it prolongs only duration of sensory
block.
DOSE
Without adrenaline :2.5mg/kg(max 175mg)
With adrenaline :3mg/kg (max 225mg)

27. CONCENTRATION USED
• For nerve block : 0.5%
• Epidural :0.125 -0.5 %(depending
whether used for sensory block or motor
block)
• Spinal : 0.5 % (heavy)

28. Side effects
• It may cause dangerous and
prolonged ventricular
dysrhythmias like tachycardia,
extrasystole
• Anxiety
• Back pain

29. CONTRAINDICATIONS
• Sensitivity to parabens.
• Beir`s block.

30. LEVOBUPIVICAINE
• Recently introduced drug.
• Not used in topical anaesthesia.
• Less cardiotoxic than bupivicaine but higher than
lignocaine.
• Neurotoxicity of levobupivicaine is also lesser
than bupivicaine.
• It is also contraindated in bier`s block and in
severe hypotension patients.
• Elimination half life is 2-2.6 hours

31. • Metabolised in liver excreated 70% by renal
and 24 % in faecal
• Dose is 2.5 mg/kg(without adrenaline).
• Duration of action is similar to bupivicaine.
• Rest of pharmocology is similar to bupivicaine

32. ROPIVACAINE
• Long acting
• It is a safer alternative to bupivicaine
• Lipid solubility is less.
• Duration of action is less as compared to
bupivicaine.
• It is less cardiotoxic than bupivicaine.
• Maximum safe dose is 3.5mg/kg BW.
• Metabolised in liver and excreted via kidneys.

33. • Available as 0.2% , 0.5% , 0.7% concentration.
• Onset of action is slow.
• Elimination half life is 108 minutes.
• Readily crosses placenta.
• Presence of epinephrine has no major effect
on onset or duration of action.

34. INDICATIONS
• Surgical anaesthesia
• Lumbar epidural (labour pain, C/S, other
surgeries
• Postop pain relief
• Intra thecal
• Peripheral nerve block
• Caudal block( in children)

35. USAGE
• Infiltration -0.2-0.5% -200mg
• PNB -0.5-1% -250mg
• Epidural -0.5-1% -200mg
• Labour pain
-0.2% 20-40mg
top ups -0.2% -20-30mg
. Caudal block -0.2% -2mg/kg

36. Warning-
. unintended intravenous inj is possible, may
result
into cardiac arrhythmias & arrest
. should be adm in incremental doses
. Not reommended for emergency situations
where fast onset of surgical anaesthesia is
required

37. Adverse effects
• Allergic
CVS-
• CNS effects occur earlier than CV, produce
convulsions at similar dose as bupivacaine.
• Inhibits platelet aggregation in plasma concentration
of 3.75mg/ml
Nausea , vomiting ,hypotension.

38. ETIDOCAINE
• Long acting drug (2-4 hours).
• Derivative of lignocaine.
• Toxicity slightly more than lignocaine, less
than bupivicaine.
• The most characteristic feature of the drug is
its ability to produce more profound effect on
motor than sensory nerves.
• Placenta transfer is little,so it can be used in
LSCS.

39. • It is used as 1-1.5% solution.
• Metabolised in liver excreted via kidneys.
• Elimination half life is 2.5 hours.
• Chemically similar to lignocaine but duration
of action is similar to bupivicane.
• Indicated for infiltration anaesthesia,
peripheral nerve block e,g brachial plexus and
central neural blocks.

40. DIBUCAINE(CINCHOCAINE)
• Longest acting local anaesthetic.
• More potent and more toxic
• Restricted in spinal anaesthesia.