For D Pharmacy students

1. P R E S E N T E D B Y - R A H U L J A D H A V
A N U S A Y A I N S T I T U T E O F P H A R M A C Y , S W A M I - C H I N C H O L I ,
D A U N D , P U N E .
General Anaesthetics

2. Introduction:
 General Anaesthetics are CNS depressant drugs,
produce partial or complete loss of sense of pain,
followed by loss of consciousness.
 Anaesthesia is controlled, reversible depression of
functional activity of CNS.
 Also depress vital function of all types of cells,

3. Stages of Anaesthesia
1. Analgesia due to depression of cortical centres.
2. Excitement due to depression of motar centres.
3. Surgical anaesthesia -
 Loss of spinal reflux
 Skeletal muscle relaxation
 Somatic muscle relaxation and disappearance of
muscle tone.

4. 4. Medullary paralysis - due to overdose.
It causes respiratory failure and vasomotar collapse.
 Active only in very high dose.
 Greater rate of metabolisam
 Biological activity is not related to chemical structure

5. Classification:
I) Inhalational anaesthetics:
1. Volatile liquids.
a) Haloginated Hydrocarbons:
eg. Chloroform, Halothane, Trichloroethylene,
Ethylchloirde.
b) Ethers: eg. Diethyl ether, vinyl ether.
2. Gases: Cyclopropane, Nitrous oxide.

6. II) Intravenous anaesthetics:
1. Barbiturates: eg. Methohexitone sodium &
Thiopentone sodium.
2. Non barbiturates:
a) Eugenol derivative: eg. Propanidid
b) Phencyclidin derivative: eg. ketamine
c) Steroids: eg. Althesin
d) Miscellaneous: eg. Etomidate, Propofol

7. 1. Methohexitone / Methohexital sodium:
• Physical properties: White powder, odourless and
hygroscopic in nature. Soluble in water.
• Chemical properties:
 Aq. Solution slowly decomposes to give cloudy solution
of methohexitone.
 With acidic solution, it gives ppt of methohexitone.

8. • Stability and storage: It is hygroscopic, hence
stored in tightly closed containers.
• Uses:
 Used Intravenously to ptoduce anaesthesia for short
procedures.
 Intravenous infusion in dilute solution to maintain
anaesthesia.

9.  Rectully used to produce anaesthesia in childrens.
• Pharmaceutical formulations:
 Methohexitone injection
• Brand names: Brevital, Brietal sodium.

10. 2. Thiopentone / Thiopental sodium:
• Physical properties: Yellowish white powder,
alliaceous odour, bitter in taste. Soluble in water,
insoluble in ether. It is hygroscopic in nature.
• Stability and storage: It is Hygroscopic and
decomposed by atm. Co2, hence stored in tightly closed
containers.

11. • Uses:
 Used as anticoagulant.
 For induction of general Anaesthesia.
 For prevention and treatment of cerebral ischaemia.
• Pharmaceutical formulations:
 Thiopentone injection
• Brand names: Pentothal sodium, Intraval sodium

12. 3. Cyclopropane:
• Physical properties:
 Colourless, inflammable gas, Characteristic odour and
BP is - 34.5°C.
 Inflammable and form explosive mixture with air.
 At N.T.P. 1 volume of gas is soluble in 2.85 volumes of
water.
 Soluble in water, liquefies as 4-6 atm. pressure.

13. • Storage: Stored in metal cylinder designed to hold
compressed gases. Kept in cool room free from
inflammable materials.
 Cylinder is painted orange.
 Shoulder should be stencilled with name / symbol
C3H6
 Name / symbol should be clearly stamped on cylinder
valve.
 Uses: It is gaseous potent anaesthetic.

14. 4. Ether:
• Diethyl ether.
• Physical properties:
 Clear, Colourless, very mobile liquid, characteristic
odour and sweet in taste.
 Very volatile and inflammable.
 1 part soluble in 10 part of water, miscible in
chloroform and alcohol.

15.  Form explosive mixture with air.
 Very slowly attacked by oxidising agent.
 It forms azeotropic mixture with Halothane.
• Chemical properties:

16. • Stability and storage:
 Oxidised by atm. Oxygen and affected by light, hence
stored in tightly closed light-resistant containers in
cool place. If cork is used as closer, it should be
protected with metal foil.
 Antioxidant like hydroquinone and propyl gallate
should be added.

17. • Label should bear,
 Very inflammable.
 Do not use near open flame or heat source.
 Name and proportion of stabilizer.
• Uses:
 Used as general Anaesthetic, given in combination with
halothane.
 Solvent ether is used as solvent.

18. 5. Halothane:
• Chemical name:
2-bromo, 2-chloro, 1,1,1-trifluoro ethane.
• Physical properties:
 Colourless, mobile, volatile heavy liquid, chloroform
like odour.
 Does not form explosive mixture with air.

19.  Slightly soluble in water, miscible in
alcohol,chloroform, ether.
 BP is 50°C.
 Form azeotropic mixture with diethyl ether.
• Stability and storage:
 Slowly decomposed on exposure to light, give
halogen acid and free halogen.

20.  Affected by air, in presence of. Moisture it attacks
lead, brass, aluminium but not copper.
 Rubber and plastics are deteriorated by it.
 Hence stored in tightly closed light-resistant containers
at temp not exceeding 25°C.
 Contains 0.01 % of w/w thymol as stabiliser.

21. • Uses: used to induce and maintain general Anaesthesia.
• Advantages:
 More potent than chloroform and ether.
 Not inflammable and not explosive when mixed with
oxygen.
 Not irritant to skin nd and mucous membrane, does not
produce necrosis of tissue.
• Brand names: Fluothane

22. 6. Trichloroethylene:
• Physical properties:
 Colourless / pale blue colour, transparent, mobile
liquid with chloroform like odour.
 Slightly soluble in water, miscible in alcohol,
chloroform and ether.
• Stability and storage:
 Stable in moisture, affected by bright light in air.

23.  Stored in tightly closed light-resistant containers in
cool place.
 It contains 0.01% w/w thymol as preservative.
 Also contains 0.001% w/w blue dye for identification
purpose.
• Uses:
 It is general Anaesthetic.
 Used by inhalation for anaesthesia in obstetrics.

24.  Used for degreasing metals.
 Used for extraction of oils and fats.
 Used in dry clean industry.
• Brand names: Trilene.