title: Influence of water deprivation on the disposition of paracetamol.
abstract: The effect of acute (96 h) water deprivation on the disposition of paracetamol (acetaminophen) has been examined in male Sprague-Dawley rats. Plasma and urinary concentrations of the drug and its two major metabolites, the glucuronide and sulphate, were determined by a sensitive and specific high performance liquid chromatographic assay. Following an intravenous dose of 100 mg kg-1 of paracetamol, no significant changes were found in the elimination rate constant (k), the mean residence time (MRT), total plasma clearance (Cl) and the apparent volume of distribution at steady-state (Vss). However, rats deprived of water for 96 h excreted a larger percentage of the administered dose as the glucuronide conjugate (15.3 vs 7.9%) and a smaller percentage as unchanged paracetamol (7.3 vs 20.7%) in the urine. In addition, there was a significant two-fold increase in the partial metabolic clearance to paracetamol glucuronide. Water deprivation also led to a significant reduction in the renal clearance of paracetamol accompanied by an increase in the renal clearance of the glucuronide.
mesh_terms: D000082:Acetaminophen / Q000378:metabolism*; D000818:Animals; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D000082:Acetaminophen