general anaesthetic

1. Chapter 5
DRUGS ACTING ON
CENTRAL NERVOUS SYSTEM
Wani Nilima .M

2. •The blood circulation to C.N.S. is very large.
• The drugs which reach C.N.S. and produce depressant effects are
called C.N.S depressants.
The C.N.S. depressant drugs are categorised as:
(1)General anaesthetics :- e.g. Diethyl ether.
(2)Hypnotics and sedatives :- e.g. Phenobarbitone.
(3) Anticonvulsants :- e.g. Phenytoin.
(4) Tranquillizers :- e.g. Chlorpromazine.
(5) C.N.S. depressants with skeletal muscle relaxant property. :-
e.g. Meprobamate.
The narcotic analgesics or True analgesics like morphine and
phethidine also selectively depress C.N.S.

3. General Anaesthetics

4. Defination :
General anaesthetics are the CNS depressant
drugs that produces a partial or total loss of
sense of pain, accompanied by loss of
consciousness.

5. Stages of anaesthesia:
1. Analgesia which is due to depression of cortical
centers.
2. Excitement which is due to depression of higher
motor centers.
3. Surgical anaesthesia which includesLoss of
spinal reflexexSkeletal muscle relaxation
Somatic-muscle relaxation and disappearance of
muscle tone.
4. Medullary paralysis which is due to overdose.

6. Classification:
Depending upon the route of administration general anaesthetics
are classified as follows,
(A) Volatile & Gaseous anaesthetics administered by inhalation :
1. Gases :-
(a) Inorganic gases : - e.g. Nitrous oxide.
(b) Hydrocarbons : - e.g. Cyclopropane, ethylene.
2. Volatile liquids: -
(a) Ether :- e.g. Diethyl ether.
(b) Halogenated hydrocarbon :- e.g. Halothane
(B) Fixed anaesthetics :-
(a) Ultra short acting barbiturates & thiobarbiturates :-
e.g. Thiopental sodium.
(b) Miscellaneous compounds :- e.g. Ketamine

7. 1. Thiopentone sodium
Chemical structure :-
Chemical Name :-
Sodium , 5- ethyl , 4,6 – dioxo , 5- pentan -2yl 1-H pyrimidine-2-
thiolate .

8. Storage and stability :
1. It is hygroscopic and is descomposed by atmospheric carbon
dioxide .
2. Hence is stored in tightly closed container .
3. It is store in the room temperature .
Uses :
1. It has use as general anaesthetics.
2. It is used as the anticonversants .
3. For the prevention and treatment of the cerebral ischaemia .
Pharmacological formulations :
Thiopentone injection I.P.
Dose : 3-5 mgkg per day .
Brand name :
1. Pentothol sodium .
2. Intraval sodium .

9. 2. Ketamine Hydyrochloride
Chemical structure :-
Chemical name :-
2-(2-chlorophenyl ) -2- (methylamino ) cyclohexan -1- one ;
hyrochloride .

10. Storage and stability :
1. Hence is stored in tightly closed container .
2. It is store in the room temperature .
Uses :
1. It has use as general anaesthetics agent .
2. It can also be used as an inducer of anaesthetics before the
administration of other anaesthetics agents .
Pharmacological formulations :
1. Ketamine hydrochloride Injection I.P.
2. Ketamine hydrochloride Tablets .
3. Ketamine hydrochloride Nasal spray B.P.
Dose :
I.V. 1 to 2 mgkg .
I.M . 3 to 5 mg kg .
Brand name :
1. ketamil
2. Ketaminol
3. ketamax
4. katalar .

11. 3. Propofol
Storage and stability : .
1. Hence is stored in tightly closed container .
2. It is store in the room temperature
Uses :
1. It has use as general anaesthetics.
2. It is used as the maintainance of general anaesthetics

12. .
Pharmacological formulations :
i. Propofol injection I.P.
ii. Propofol Tablet
iii. Propofol Syrup
iv. Propofol cream
v. Propofol Gel
vi. Propofol liquid .
Dose :
I.V. bolus 2 mgkg for induction .
Brand name :
1. Celofol
2. Critifol