title: Hepatic drug clearance in patients with mild cystic fibrosis.
abstract: The plasma disposition of three model substrates (lorazepam, indocyanine green, and antipyrine) and the formation clearance of antipyrine metabolites (3-hydroxymethylantipyrine, norantipyrine, and 4-hydroxyantipyrine) were evaluated in 15 subjects with mild cystic fibrosis and in 15 healthy control subjects. Plasma clearance was significantly greater in patients with cystic fibrosis for both lorazepam (1.7 +/- 0.4 versus 1.2 +/- 0.5 ml/min/kg) and indocyanine green (14.2 +/- 6.1 versus 9.1 +/- 3.0 ml/min/kg). In contrast, the clearance of antipyrine was not significantly different (1.0 +/- 0.7 versus 0.8 +/- 0.3 ml/min/kg), but the formation clearance for 3-hydroxymethylantipyrine was significantly greater in patients with cystic fibrosis. Lorazepam and antipyrine apparent steady-state volume of distribution were not different between groups. These results suggest that clearance of drugs that undergo conjugation (e.g., lorazepam) or biliary excretion (e.g., indocyanine green) is increased in patients with mild cystic fibrosis. In contrast, the increased formation clearance of only one antipyrine metabolite suggests that alterations in clearance of drugs metabolized by cytochrome P450 enzymes are substrate specific and isoform specific in patients with cystic fibrosis.
authors.affiliation: Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Kearns
authors.forename: W R
authors.initials: WR
authors.lastname: Crom
authors.forename: K H
authors.initials: KH
authors.lastname: Karlson
authors.forename: G B
authors.initials: GB
authors.lastname: Mallory
authors.forename: W E
authors.initials: WE
authors.lastname: Evans
mesh_terms: D000293:Adolescent; D000328:Adult; D014151:Anti-Anxiety Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D000983:Antipyrine / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D001646:Bile / Q000378:metabolism; D002648:Child; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000493:pharmacokinetics*; D003550:Cystic Fibrosis / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005260:Female; D006801:Humans; D007208:Indocyanine Green / Q000378:metabolism / Q000493:pharmacokinetics; D007262:Infusions, Intravenous; D008099:Liver / Q000378:metabolism*; D008140:Lorazepam / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D008297:Male; D012044:Regression Analysis; D013329:Structure-Activity Relationship
chemical_list: D014151:Anti-Anxiety Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004396:Coloring Agents; D003577:Cytochrome P-450 Enzyme System; D007208:Indocyanine Green; D008140:Lorazepam; D000983:Antipyrine