Action of i. v. thiopentone is terminated by ?

Ans. is 'c' i.e., Redistribution Three proceeses are involved in the termination of action of barbiturates: the relative impoance of each varies with the compound. Redistribution: it is impoant in the case of highly lipid soluble thiopentone. After iv injection the action of thiopentone is terminated in 6-10 mins by redistribution while the ultimate disposal occurs by metabolism (tl/ 2 of elimination is 9 hours). Metabolism: drugs with intermediate lipid solubility (sho acting barbiturates) are primarily metabolized in liver by oxidation, dealkylation and conjugation. Their plasma t1/2 ranges from 12 - 40 hours. Excretion: barbiturates with low lipid solubility (long acting agents) are significantly excreted unchanged in urine. The t1/2 of phenobarbitone is 80-120 hours. Alkalinization of urine increases ionization and excretion.