1. LOCAL ANESTHETICS
Dr Akasha Ambar Awan
PGR Plastic Surgery
(1st YEAR)

2. DEFINITION OF LOCAL
ANESTHESIA

3. STRUCTURE
• Aromatic moiety
• Intermediate chain
• Amine amoiety

4. CLASSIFICATION OF LOCAL ANESTHETICS
Esters
Am”i”des
Procaine (Novacaine)
L”i”docaine
Chloroprocaine
Bup”i”vacaine (Marcaine)
Tetracaine
Pr”i”locaine
Cocaine
Mep”i”vacaine,
Et”i”docaine

5. PHARMACOLOGY OF LOCAL
ANESTHETICS

6. PHARMACOLOGY OF LOCAL
ANESTHETICS
Properties:
esters
amides
Hydrolyzed by plasma
Pseudochilnesterase
Metabolized in liver
Unstable in solution
Stable in solution
Likely to cause allergenic
reactions
Not allergic
*Vasodilating property (except cocaine)

7. Drug
Onset
Maximum Dose
(with Epinephrine)
Duration
(with Epinephrine)
Lidocaine
10-20 min 4.5 mg/kg (7 mg/kg)
120 min (240 min)
Mepivacaine
10-20min
5 mg/kg (7 mg/kg)
180 min (300 min)
Bupivacaine
15-30min
2.5 mg/kg (3 mg/kg)
360-720 hours (8 h)
Procaine
Rapid
8 mg/kg (10 mg/kg)
45 min (90 min)
Chloroprocaine
Rapid
10 mg/kg (15 mg/kg)
30 min (90 min)
Etidocaine
10-20min
2.5 mg/kg (4 mg/kg)
360-720min (8 h)
Prilocaine
10-20min
5 mg/kg (7.5 mg/kg)
180-300min (360 min)
Tetracaine
20-30min
1.5 mg/kg (2.5 mg/kg)
300-600min (10 h)

8. ORDER OF BLOCKADE
• The order of blockade:
Pain –> temperature – > postural, touch and
pressure and vibration – > motor fibres.
Tongue: bitter –> sweet –> sour –> salt

9. AN IDEAL LOCAL ANESTHETIC
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Reversible action.
Non-irritant.
No allergic reaction.
No systemic toxicity.
Rapid onset of action.
Sufficient duration of action.
Potent.
Stable in solutions.
Not interfere with healing of tissue.
Have a vasoconstrictor action or compatible with VC.
Not expensive

10. ADDITION OF VASOCONSTRICTOR
(EPINEPHRINE)
• Why do we need to add???
▫ Clear field & hemostasis
▫ Prolonged action by limiting systemic drug
absorption
▫ Lower risk of toxicity/ and intravascular injection

11. EPINEPHRINE WITH LOCAL
ANESTHETIC
• The dilution of vasoconstrictors referred to as a ratio i.e., 1:50,000;
1:100,000; 1:200,000 etc,…
• A concentration of 1:1,000 means :
▫ 1 gram(1000 mg) of solute (drug) contained in 1000 ml (1 L) of
solution, therefore, 1:1,000 dilution contains 1000 mg in 1000 ml or 1.0
mg/ml of solution (1000 ug/ml)
• 1:1,000 is very concentrated (strong)
• much more dilute forms: for example, 1:50,000 > 1:100,000 > 1:200,000
• (1:100,000 = 0.01 mg/1 ml of solution)
• The maximum amount of 2% Lidocaine 1:100,000 epinephrine that
can be used is 300 mg which is 8.3 cartridges regardless of the
patient’s weight.

12. CONTRAINDICATIONS OF LOCAL
ANESTHETICS WITH
VASOCONSTRICTOR
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Hypertension
Coronary heart disease
Arrythmias
Already using MOA
• Epinephrne+local anesthetic solution should not used in
proximity to end arteries
▫ (fingers,toes,penis,nose tip,ear lobules)

14. SIDE EFFECTS
• Allergic effects
▫ Esters, epinephrine
• CNS toxicity
▫ At lower toxic dose, easily cross BBB
▫ initial excitatory effects on body & CVS
 ( tinnitus, light headedness, tremors,slurred speech, audiovisual
disturbance, metallic taste, numb lips and tongue)
▫ At more high doses: Grandmal seizures and later CNS
depression
• CVS toxicity
▫ Hypotension,arrythmias, myocardial depression

20. TYPES OF LOCAL ANESTHESIA
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Topical anesthesia
Local infilteration
Peripheral nerve blocks
Tumescent technique

21. TOPICAL/SURFACE ANESTHESIA
• Uses :
▫ Oral surgeries, nasal intubation, superficial surgical procedure
• Advantages :
▫ technically easy
▫ minimal equipment
• Disadvantages :
▫ potential for large doses leading to toxicity

22. COCAINE SUBSTITUTIONS
• lidocaine (Xylocaine) -oxymetazoline (Afrin)
combinations.
• tetracaine (pontocaine)-oxymetazoline (Afrin)
combinations.
• Tetracaine (pontocaine) (1%-2%).
• Lidocaine (Xylocaine) (2%-4%).
• benzocaine

23. TOPICAL ANESTHETIC SPRAY

25. COMBINATION OF LOCAL
ANESTHETICS
Definition: eutectic mixture of local anesthetics (EMLA) .
( lowest melting point)

27. LOCAL INFILTERATION/FIELD
ANESTHESIA
• Uses:
▫ Suturing, minor superficial surgery, line placement, more
extensive surgery with sedation
• Advantages:
▫ minimal equipment, technically easy, rapid onset
• Disadvantages:
▫ potential for toxicity if large field

29. PERIPHERAL NERVE BLOCK
• Minor nerve block
• Major nerve block
▫ Plexus block
▫ i.v.block e.g. beir block

30. I.V BLOCK/BIER BLOCK
• Uses
▫ any surgical procedure on an extremity
• Advantages:
▫ technically simple, minimal equipment, rapid onset
• Disadvantages:
▫ duration limited by tolerance of tourniquet pain, toxicity

31. Minor nerve block
•Injecting local anesthetic near the
course of a named nerve
•Uses:
• Surgical procedures in the
distribution of the blocked nerve
•Advantages:
•relatively small dose of local
anesthetic to cover large area;
rapid onset
•Disadvantages:
•technical complexity,
neuropathy

33. PLEXUS BLOCKAGE
• Injection of local anesthetic adjacent to a plexus,
e.g cervical, brachial or lumbar plexus
• Uses :
▫ surgical anesthesia or post-operative analgesia in the
distribution of the plexus
• Advantages:
▫ large area of anesthesia with relatively large dose of
agent
• Disadvantages:
▫ technically complex, potential for toxicity and
neuropathy.

37. TUMESCENT TECHNIQUE
• Large volumes of local anesthetic lidocaine (0.05%-1%) with
diluted EPI (1:500,000 to 1:1,000,000) for both anesthetic and
hemostatic effects.
• Safe technique,less toxicity levels, tissue plane for dissection
• For example, a mixture of 1000 mL of normal saline with 25 mL
of 2% lidocaine,I g/ml adrenaline will result in a concentration of
lidocaine upto .05%,adrenaline in 1:1000,000.
• maximum dose of lidocaine with epinephrine=7 mg/kg during
routine use. However, when used for tumescence during
liposuction, this ceiling is dramatically increased to 35 mg/kg
(others report up to 55 mg/kg)

38. Recipe for Tumescent Technique Anesthetic Solutions
for Body Liposuction
• (Lidocaine 0.05%, Epinephrine 1:1,000,000
Lidocaine:
500 mg (50 ml of 1% lidocaine solution)
Epinephrine:
1 mg (1 ml of 1:1,000 solution of epinephrine)
Sodium bicarbonate:
12.5 mEq (12.5 ml of an 8.4%
NaH2CO3 solution
Normal saline:
1000 ml of 0.9% NcC1 solution

39. Typical Range of Volumes of Dilute Anesthetic Solutions
Used with the Tumescent Technique for Infiltration into
Various Areas
Abdomen, upper and lower
(800 to 2000 ml)
Hip (flank, or love handle), each side
(400 to 1000 ml)
Lateral thigh, each side
(500 to 1200 ml)
Anterior thigh, each side
(600 to 1200 ml)
Proximal medial thigh, each side
(250 to 600 ml)
Knee
(200 to 500 ml)
Male breast, each side
(400 to 800 ml)
Submental chin
(100 to 200 ml)

41. THANK YOU