An i.v. bolus dose of thiopentone leads to loss of consciousness within 10-15 sec. The patient regains consciousness in just a few minutes. This is because it is:

(Ref: KDT 6/e p374) Thiopentone and other highly lipid soluble agent 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.