title: Perturbation of paracetamol urinary metabolic ratios by urine flow rate.
abstract: The effects of high and low urine flow rates on the urinary metabolic ratios for paracetamol glucuronidation, sulphation and oxidation were determined at steady-state in seven healthy young adult volunteers. Metabolic partial clearances were unaffected by urine flow rate, but individual paracetamol metabolic ratios varied 2.5- to 3.2-fold over a 7.4-fold range of urine flow rates (0.81-6.00 ml min-1). The change in metabolic ratios was due entirely to a 2.5-fold change in renal clearance of unchanged paracetamol. These data emphasise the limitations of the metabolic ratio as a measure of intrinsic clearance for compounds which undergo some degree of tubular reabsorption.
authors.affiliation: Department of Clinical Pharmacology, Flinders Medical Centre, Adelaide, Australia.
authors.forename: J O
authors.initials: JO
authors.lastname: Miners
authors.forename: N J
authors.initials: NJ
authors.lastname: Osborne
authors.forename: A L
authors.initials: AL
authors.lastname: Tonkin
authors.forename: D J
authors.initials: DJ
authors.lastname: Birkett
mesh_terms: D000082:Acetaminophen / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate
chemical_list: D000082:Acetaminophen