The document discusses local anesthetics, including their definition, requirements, mechanisms of action, classifications, and biotransformation. It notes that local anesthetics work by inhibiting sodium influx through voltage-gated sodium channels in neuronal cells, blocking nerve conduction. Local anesthetics are classified based on duration of action, chemical nature, and origin. Common examples are discussed and appropriate uses along with potential complications and contraindications are outlined.

1. ARJUN SHENOY
POSTGRADUATE STUDENT
DEPT OF MAXILLOFACIAL SURGERY
KVGDCH

2.  Definition
 Requirements
 composition
 Mechanism of action
 Classification
 Biotransformation
 Indications and contraindications

3. The word was coined by Dr Oliver Holmes 1846
•Greek word.
•An means without and aisthetos means pain.
• Anesthesia means loss of sensation including
pain, touch, temperature and pressure perception
and may be accompanied by impairment of motor
function

4.  Nonirritant.
 Should not produce any local reaction.
 Should not cause any permanent change in the
nerve structure.
 Should cause minimal systemic toxicity.
 Should be effective and enough penetrating
properties when used topically.
 Should have short time of onset.

5.  Duration should enough to allow the
completion of procedure.
 Should have enough potency.
 Should be free from allergy producing
substances.
 Should be sterilized of capable of being
sterilized by heat without deterioration.
 Should be stable and readily undergo
biotransformation in the body.

6. AGENT FUNCTION
LIGNOCAINE HYDROCHLORIDE 2% LOCAL ANAESTHETIC AGENT
ADRENALINE 1:80000 VASOCONSTRICTOR
SODIUM METABISULFATE REDUCING AGENT
METHYLPARABEN PRESERVATIVE

7. DISTILLED WATER DILUTING AGENT
RINGERS SOLUTION VEHICLE
SODIUM HYDROXIDE TO ADJUST PH
NITROGEN BUBBLES PREVENTS DESTRUCTION OF
VASOPRESSOR BY OXYGEN

8.  Acetylcholine theory.
 Calcium displacement theory.
 Surface charge theory.
 Membrane expansion theory.
 Specific theory.

9.  Local anaesthetics are membrane stabilizing
drugs.
 Acts by inhibiting sodium influx through
voltage gated sodium specific ion channels in
the nueronal cells.
 Hence action potential cannot arise due to
this inhibition and blockade of conduction is
established.

13.  PAIN
 TEMPERATURE
 TOUCH
 PROPRIOCEPTION
 SKELETAL MUSCLE TONE
INITIALLY GRADE C
FIBRES ARE BLOCKED
FOLLOWED BY GRADE A

14. ON THE BASIS OF
DURATION OF ACTION
BASED ON
ORGIN
ON BASIS OF
CHEMICAL
NATURE

15. ON BASIS OF OCCURANCE

16.  On the basis if OCCURRENCE in nature:
 NATURALLY OCCURING:
 e.g. cocaine.
SYSTEMIC COMPOUNDS
 Derivatives of acentanillide: e.g. lignocaine
(lidocaine, xylocaine)
l
 Miscellaneous drugs with local anesthetic
action like phenol, chlorpromazine

17.  ESTERS
These can be further classified as:
Esters of benzoic acid
e.g. cocaine butacaine.
Esters of para-aminobenzoic acid
e.g. procaine, propoxycaine.
 AMIDES
e.g. articaine, bupivacine, lidocaine.

18.  short acting
articaine, lidocaine, mepivacaine, prilocaine.
 Long acting:
bupivacaine, etidocaine, bucricaine

19.  Incision and drainage of incised abscess.
 Removal of cysts, residual infection areas,
hydrophilic groups and neoplastic growths,
ranula and salivary calculi.
 In the treatment of tic douloreux by
producing prolonged anesthesia with the
combination of a local anesthetic agent and
alcohol injection.

20.  Extraction of teeth and fractured roots.
 Odontectomy.
 Treatment of alveolagia.
 Alveolectomy.
 Apicoectomy.

21.  Esters are rapidly metabolised in the plasma
by cholinestrase
 Amides are slowly destroyed in the liver by
microsomal P450 enzymes

22. LIPID
SOLUBILITY
PH of the
inflamed
tissues
vasoconstrictors

23.  Premonitory signs
 Ringing in ears
 Metallic taste
 Numbness around lips
MORE SERIOUS COMPLICATIONS-
 First apparent convulsions followed by CNS
depression (death).
 CVS – arryhythmias and hypotension.

25. MODES OF APPLICATION
TOPICAL OR SURFACE APPLICATION
INFILTRATIONS
NERVE BLOCKS
FIELD BLOCKS
CENTRALLY ACTING (SPINAL)

26.  Methhaemoglobinemia
 neurotoxicity
 hypersensitivity

27. ABSOLUTE
CONTRAINDICATION.
RELATIVE
CONTRAINDICATION

28.  History of allergy to local anesthetic agent, or
history of allergy to any of the constituents of
the local anesthetic solution.

29. ◦ Fear and apprehension.
◦ Presence of acute inflammation or suppurative
infection at the site of insertion of needle.
◦ Infants or small children.
◦ Mentally retarded patients.

30. ◦ Major surgical procedures with
haemodynamic unstability
epilepsy
◦ Presence of methhaemoglobinemia. Two
drugs are to be avoided. They are
benzocaine and articaine.
 Presence of atypical plasma cholinesterase

31.  1)patient remains awake and cooperative.
 2)little disturbance of normal physiology.
 3)low incidence of morbidity.
 4)patient can leave the hospital unescorted.
 5)additional personnel not required.

32.  6)percentage of failure is small.
 7)technique not difficult master.
 8)no additional expense to the patient.
 9)Patient need not miss the previous meal.

33.  No true disadvantages to the use of regional
anesthesia, when the patient is mentally
prepared and when there are no
contraindications.

34.  Potency: depends solely on the chemical
nature.
 Duration of anesthesia: depends on
molecular weight and presence of
vasoconstrictor
 If lipophillic group predominates then the
ability to diffuse into the lipid rich nerve
diminishes.

35. NORMAL
HEART FAILURE
1.8 hr
1.9 hr
HEPATIC DISEASE
RENAL DISEASE
4.9 hr
1.3 hr