This is my 24th ppt! Its on LOCAL ANESTHETICS.............It comprises varying drugs, their potencies, and other details.... Useful for 2nd year students.....and for reference! Do check...n send ur reviews! Thank you! @rxvichualwz4uh! :) :)

1. LOCAL
ANAESTHETICS – A
BRIEF OUTLOOK
PRESENTED BY :
VISHNU.R.NAIR,
FOURTH YEAR PHARM.D,
NATIONAL COLLEGE OF PHARMACY (NCP),
KERALA UNIVERSITY OF HEALTH
SCIENCES (KUHS).

2.  DEFINITION  :
“ LOCALANAESTHETICS (LAs) are agents, which when applied
LOCALLY to NERVETISSUE, in APPROPRIATE CONCENTRATIONS,
cause BLOCKADE of ACTION POTENTIALS responsible for NERVE
CONDUCTION”……….

3.  CLASSIFICATION  :
LAs are classified into:
A. INJECTABLE ANAESTHETICS :
I. LOW POTENCY, SHORT DURATION LAs:
- PROCAINE
- CHLOROPROCAINE
II. INTERMEDIATE POTENCY & DURATION LAs:
- LIDOCAINE (LIGNOCAINE)
- PRILOCAINE

4. III. HIGH POTENCY, LONG DURATION LAs:
- TETRACAINE(AMETHOCAINE)
- BUPIVACAINE
- ROPIVACAINE
- DIBUCAINE(CINCHOCAINE)
B. SURFACE/ TOPICAL ANAESTHETICS:
I. SOLUBLE LAs:
- COCAINE
- LIDOCAINE
- TETRACAINE
- BENOXINATE

5. II. INSOLUBLE LAs:
- BENZOCAINE
- BUTYLAMINOBENZOATE(BUTAMBEN)
- OXETHAZAINE……………………………….

6.  MECHANISM OF ACTION  :
LOCAL ANAESTHETICS  bind toVOLTAGE-GATED
SODIUM CHANNELS  BLOCK them  REDUCES
PERMEABILITY of EXCITABLE MEMBRANES to
SODIUM  PROGRESSION of ANAESTHETIC action in
the nerve  INCREASESTHRESHOLD for ELECTRICAL
EXCITABILITY  REDUCES ACTION POTENTIAL 
REDUCES IMPULSE CONDUCTION Thus, NERVE
CONDUCTION is REDUCED………………………..

7. TYPE OF NERVE
FIBRE
LOCATION FUNCTION SENSITIVITY TO
BLOCK
I. ‘A’ FIBERS:
- A(ALPHA) MUSCLES & JOINTS MOTOR &
PROPRIOCEPTION
MOTOR(+) ;
PROPRIOCEPTION(++)
- A(BETA) MUSCLES& JOINTS MOTOR &
PROPRIOCEPTION
MOTOR(+);
PROPRIOCEPTION(++)
- A(GAMMA) EFFERENT TO MUSCLE
SPINDLES
MUSCLETONE ++
- A(DELTA) SENSORY ROOTS;
AFFERENT PERIPHERAL
NERVES
PAIN,TEMPERATURE,
TOUCH
+++
II. ‘B’ FIBERS: PREGANGLIONIC;
SYMPATHETIC
VASOMOTOR,
PILOMOTOR,
SUDOMOTOR
++++
III. ‘C’ FIBERS

8. NOTE:
‘C’ FIBERS comprise 2 subdivisions:
A. SYMPATHETIC NERVE FIBER
B. DORSAL ROOT NERVE FIBER
- SYMPATHETIC NERVE FIBER has same location, function & block sensitivity as ‘B’ fiber
- DORSAL ROOT NERVE FIBER has same location, function & block sensitivity as ‘A DELTA’
fiber………………

9.  ADVERSE DRUG EFFECTS :
I. CNS EFFECTS:
- Restlessness
- Tremor
- Clonic convulsions
- CNS depression
- Coma
- Death (due to RESPIRATORY FAILURE)
II. CVS EFFECTS:
- Bradycardia -Vascular collapse
- Hypotension - Arrhythmias

10. III. SMOOTH MUSCLE EFFECTS:
- Reduced intestinal & bowel contractions
IV. LOCAL SITE EFFECTS:
- Delayed wound healing
- Tissue necrosis (especially when a potent vasoconstrictor is added)
V. HYPERSENSITIVITY EFFECTS:
- Rashes - Dermatitis
- Angioedema - Anaphylaxis………………

11.  DRUGS, AT A GLANCE  :
1. COCAINE:
- DRUG  acts as LA, along with LOCALVASOCONSTRICTION  blocks nerve impulses
- ADRs:
a. DRUG  REDUCES REUPTAKE of CATECHOLAMINES in CNS(especially DOPAMINE) 
produces EUPHORIA
b. MYDRIASIS
- USE:TOPICAL ANAETHESIA of UPPER RESPIRATORYTRACT (1%; 4% solutions)………..

12. 2. LIDOCAINE (XYLOCAINE):
- FASTER & LONGER ACTING
- AMIDE LA
- Used for people SENSITIVE to ESTER-TYPE LAs
- ADRs:
a. Dysgeusia
b. Twitching
c. Respiratory depression
- USES:
a. LA
b. Anti-arrhythmic……………………………………

13. 3. BUPIVACAINE (SENSORCAINE):
- WIDELY USED AMIDE LA
- Causes PROLONGED ANAESTHESIA
- ADRs:
a. Ventricular arrhythmia (malignant)
b. Myocardial depression
- USES:
a. Prolonged analgesia during labor
b. Postoperative analgesia…………………..

14. IV. ARTICAINE(SEPTOCAINE):
- Rapid onset of action (1-6 mins)
- Duration of action: 1 hour
- Amide LA
- Used for DENTAL & PERIODONTAL PROCEDURES…………………

15. V. CHLOROPROCAINE(NESACAINE):
- ESTER LA
- Rapid onset
- Short duration of action
- ADRs:
a. Prolonged sensory & motor block
b. Muscular back pain…………………………………….

16. VI. ETIDOCAINE(DURANEST):
- Long acting AMIDE LA
- Used in SURGERY, involving INTENSIVE SKELETAL MUSCLE RELAXATION
- ADR : Cardiotoxicity……………

17. VII. MEPIVACAINE(POLOCAINE):
- AMIDE LA
- Intermediate acting
- More toxic to NEONATES, than ADULTS, so it should be avoided in OBSTETRICAL
ANAESTHESIA………………………

18. VIII. PRILOCAINE(CITANEST):
- AMIDE LA
- Intermediate acting
- Lesser incidence of CNSTOXICITY
- ADR : METHEMOGLOBINEMIA(in such conditions, treat with METHYLENE BLUE, at a
dose of 1-2 mg/kg)………………………

19. IX. PROCAINE(NOVOCAIN):
- FIRST SYNTHETIC LA
- AMINO ESTER
- Has less potency and duration of action
- Drug  metabolizes into PABA(Para-amino benzoic acid)  thus avoid usage in patients
having SULFONAMIDES
- USES:
a. Infiltration anesthesia
b. Diagnostic nerve blocks…………………………

20. X. ROPIVACAINE (NAROPIN):
- Long lasting AMIDE LA
- Low incidence of CARDIOTOXICITY
- Used in EPIDURAL & REGIONAL ANESTHESIA……………

21. XI. TETRACAINE(PONTOCAINE):
- Long acting AMINO ESTER
- Increased POTENCY, & DURATION OF ACTION
- Used mainly in SPINAL ANESTHESIA
- Has high risk of SYSTEMICTOXICITY………………………………..

22. XII. DIBUCAINE(NUPERCAINAL):
- Used as SPINAL ANESTHETIC
- Also used as CREAM & OINTMENT forTOPICAL USE
- Not used as injection(due to increasedTOXICITY)………………………

23. XIII. DYCLONINE HYDROCHLORIDE(DYCLONE):
- Has rapid onset of action
- Increased duration of action
- USES:
a. Topical anesthesia during ENDOSCOPY(0.5-1% solution)
b. For oral mucositis pain, due to radiation/ chemotherapy
c. Anogenital procedures
d. Sore throat(as lozenges)
e. Contact dermatitis(0.75% solution)………………….

24. XIV. PRAMOXINE HYDROCHLORIDE (ANUSOL):
- Too toxic for eye/ nose application
- Mainly used as 1%TOPICAL APPLICATION …………………..

25. XV. BENZOCAINE(AMERICAINE):
- Poorly soluble
- Used onWOUNDS & ULCERATED SURFACES for sustained LOCALIZED ACTION
- ADR : Methemoglobinemia………………………………..

26. XVI. PROPARACAINE(ALCAINE):
- Reduced irritation
- Used in patients SENSITIVETO ESTER LAs
- Mainly restricted to OPTHALMOLOGICAL USE…………………………

27. XVII. TETRODOTOXIN & SAXITOXIN:
- Block SODIUM CHANNEL PORE
- Derived from JAPANESE PUFFER FISH
- ADRs:
a. Respiratory muscle paralysis
b. Hypotension……………………………………

28.  GENERAL USES OF LAs  :
Comprise:
1. SURFACE ANESTHESIA
2. INFILTRATION ANESTHESIA
3. CONDUCTION BLOCK
4. SPINAL ANESTHESIA
5. EPIDURAL ANESTHESIA
6. I.V REGIONAL ANESTHESIA

29. 1. SURFACE ANESTHESIA:
- Drugs used include:
a. LIDOCAINE
b. PRILOCAINE, etc………….

30. 2. INFILTRATION ANESTHESIA:
- Dilute solution of LA  infiltrated under SKIN in area of OPERATION  BLOCKS
SENSORY NERVE ENDINGS
- Drugs used include:
a. LIDOCAINE
b. BUPIVACAINE etc………………..

31. 3. CONDUCTION BLOCK:
- LA  injected around nerve trunks  area, FAR from site of injection is ANESTHETIZED &
PARALYZED
- Mainly FIELD BLOCK & NERVE BLOCK is achieved
- Drugs used include:
a. LIDOCAINE
b. BUPIVACAINE, etc…………………………

32. 4. SPINAL ANESTHESIA:
- LA  injected in SUBARACHNOID SPACE, in between L(2-3) / L(3-4) , below lower part of
SPINAL CORD  LOWER ABDOMEN & HIND LIMBS are ANESTHETIZED & PARALYZED
- Drugs used include:
a. LIDOCAINE
b. BUPIVACAINE
c. TETRACAINE, etc
- Complications include:
a. RESPIRATORY PARALYSIS
b. HYPOTENSION
c. HEADACHE
d. SEPTIC MENINGITIS

33. e. NAUSEA &VOMITING
f. CAUDA EQUINA SYNDROME (Prolonged loss of control over bladder & bowel
sphincters)………………

34. 5. EPIDURAL ANESTHESIA:
- LA  injected into SEMILIQUID FAT of SPINAL DURAL SPACE  causes MULTIPLE
PARAVERTEBRAL BLOCKS
- Sites of injection include:
a. Thoracic
b. Lumbar
c. Caudal
- Drugs used include:
a. Lidocaine
b. Bupivacaine………………………

35. 6. I.V REGIONAL ANESTHESIA:
- Also known as INTRAVASCULAR INFILTRATION ANESTHESIA
- LIDOCAINE is used here………………………………..

36.  REFERENCE/ BIBLIOGRAPHY  :
• Catterall.A.W; Mackie.K; “Chapter 14: Local Anesthetics”; Goodman & Gilman’s
Pharmacological Basis ofTherapeutics; 11th edition; McGraw-Hill Publications; Page: 369-
386
• Tripathi.D.K; “Chapter 26: Local Anesthetics”; Essentials of Medical Pharmacology; 7th
edition; Jaypee Publishers; Page: 360-371

37. THANK YOU!!!   