Action of i. v. thiopentone is terminated by -
Ans. is 'c' i.e., Redistribution {Ref: K D Tripathi 7th/e p. 400]o Three proceeses are involved in the termination of action of barbiturates: the relative importance of each varies with the compound.i) Redistribution: it is important 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 (short acting barbiturates) are primarily metabolized in liver by oxidation, dealkylation and conjugation. Their plasma tl/2 ranges from 12-40 hours.Excretion: barbiturates with low lipid solubility (long acting agents) are significantly excreted unchanged in urine. The tl/2 of phenobarbitone is 80-120 hours. Alkalinization of urine increases ionization and excretion.Long acting barbituratesShort acting barbituratesUltrashort acting---Phenobarbitone, Mephobarbitone.Butobarbitone, secobarbitone, Pentobarbitone.Thiopentone, Methohexitone, Hexobarbitone.
Rapidly renal excretion
Oxidation
Redistribution
Conjugation
Anaesthesia