pharmaclogy of local anesthetics

1. Dr. Haji Bahadar
Khyber Medical University-IPMS

2. Anaesthesia means temporary loss of
sensation or awareness. It includes
analgesia (relief from pain), muscle
relaxation, amnesia (loss of memory), or
unconsciousness.

3.  Relief from pain
 Amnesia
Anesthesia enables the painless performance
of medical procedures that would cause severe or
intolerable pain to an unanesthetized patient.

4. 1. General anesthesia suppresses central nervous system
resulting in unconsciousness and total lack
of sensation.
2. Local anesthesia: anesthesia that affects a restricted
area of the body. blocking transmission of nerve
impulses between a targeted part of the body and the
central nervous system, causing loss of sensation in
the targeted body part.
Local anesthesia numbs a specific part of the body to prevent
any feeling of pain.

5. Those drugs which cause local loss of sensations

6.  Those drugs which cause local loss of sensations

10. Na+ channels are present in all nerves. Local
anesthetics block these channels and prevent action
potential generation and conduction.

13. Causes
 drug overdose
 IV injection
 rapid absorption from hight vascular area
 accumulation of multiple injections or infusion

14.  numbness of tongue
 restlessness
 tinnitis
 vertigo
 shivering
 muscular twitching & tremors (initially involving
muscles of face & distal parts of extremities)
 generalised convulsions

15. Initial
 hypertension & tachycardia
 Then
peripheral vasodialatation, profound hypotension -
> decreased Q sinus bradycardia, intracardiac
conduction defects (prolonged PR & QRS
complex), ventricular arrhythmias, cardiac arrest.

16.  IV infusion of a 20% lipid emulsion (eg, Intralipid
20%) has become an accepted part of treatment for
systemic toxicity from local anesthetics, and
particularly for cardiac arrest.
 Manage convulsions
Others according to protocol
 positive inotropes
 amiodarone