General anaesthetics are often defined as compound that induce a loss of conciousness in human or loss of righting reflex in animals.

1. GENERAL
ANAESTHSIA
Prepared by Abul hasan mollick
(Bachelor degree of pharmacy)

2. INTRODUCTION
• General anaesthesis areCNS Depressant that produce anaesthesia, which extends to
the entire body , and are characterize by a state of unconsciousness,analgesia, and
amnesia with skeletal muscle relaxation and loss of reflex
• Gneral anaesthesia are employed for surgical operations , four stages of anaesthsis
may recognise as
• STAGE1: the patient are conscious and experience sensations of warmth,
remoteness, drifting , falling, giddiness. This stages are often used in minor surgery

3. CONT……..
• STAGE2: This stages begins with the loss of conciouness. Depressions of
higher centre produces a veriety of effect including excitement involuntary
activity increase skeletal muscle tone and respirations
• STAGE3: Also knowen as surgical anaesthesia .this is the stage
unconsciousness and paralysis of reflex . Respirations is regular and blood
pressure is maintained . All surgical procedure are carried out in this stages
• STAGE4: Alao known as medullary paralysis . Respiratory and circular
failure occure in this stage

4. MECHANISMN ACTION OF GA
• Three mechanism are are
• 1. HYDRATE HYPOTHESIS: Anaesthetic molecule can form hydrate with
saturated water , which can stop brain functions in corresponding area .
However the correlations between the ability to form hydrate
• 2.ION CHANNEL HYPOTHESIS: Anaesthetic block ion channel by
interacting with cellular membrane and reducing the flow of Na+ ion and
increasing the K+ ion in to the cell, which lead to the development of
anaesthesia

5. CONT……
• 3. FLUIDE MEMBRNE HYPOTHESIS: Anaesthetic stabilise or rather
immobilise , the cell membrane, hampering the membrane fluidity, which
produce change in the ion channel action.

6. CLASSIFICATIONS OF GA
• 1. INHALATIONL ANAESTHETICS:
• LIQUID: enflurane , isoflurane
• GAS: cyclopropane , nitrous oxide
• 2. INTRAVENOUS ANAESTHETICS:
• Ultrashort acting barbiturate: thiopantane, thiamylal
• Arylcyclohexylamine: ketamine

7. CONT……
• Benzodiazipine: midazolam
• Nercotic analgesic: alfentanil, fentanyl
• Miscellaneous: propofol

8. SYNTHESIS OF THIOPANTAL SODIUM

9. SYNTHESIS OF THIAMYLAL SODIUM

10. SYNTHESIS OF KETAMINE