An i.v. bolus dose of thiopentone leads to loss of consciousness within10-15 sec. The patient regains consciousness in just a few minutes. This is because it is:
Renally excreted
Exhaled rapidly
Rapidly metabolised by hepatic enzymes
Redistributed from brain to other body tissues
Thiopentone - is highly lipid soluble agent - it first reach the highly perfused organs like brain - Therefore, onset of action of these agents is very quick. However, action also terminates quickly because of redistribution to less well perfused tissues like fat and muscle.
Anaesthesia