title: Digoxin-verapamil interaction: reduction of biliary but not renal digoxin clearance in humans.
abstract: The interaction between digoxin and verapamil was studied in six patients (mean age +/- SD, 61 +/- 5 years) with chronic atrial fibrillation. The effects of adding verapamil (240 mg/day) on steady-state plasma concentrations and renal and biliary clearances of digoxin were studied in a crossover manner. The biliary clearance of digoxin was determined by a duodenal perfusion technique. Verapamil induced a 44% increase in steady-state plasma concentrations of digoxin, from 0.80 +/- 0.24 to 1.15 +/- 0.40 nmol/L (p less than 0.01). The biliary clearance of digoxin decreased by 43%, from 187 +/- 89 to 101 +/- 55 ml/min (p less than 0.05), in the presence of verapamil, whereas the renal clearance was unaffected (153 +/- 31 versus 173 +/- 51 ml/min; difference not significant). Our results indicate that the main inhibitory effect of verapamil on digoxin elimination is on the biliary route.
authors.affiliation: Department of Clinical Pharmacology, Karolinska Institute, Huddinge University Hospital, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Hedman
authors.forename: B
authors.initials: B
authors.lastname: Angelin
authors.forename: A
authors.initials: A
authors.lastname: Arvidsson
authors.forename: O
authors.initials: O
authors.lastname: Beck
authors.forename: R
authors.initials: R
authors.lastname: Dahlqvist
authors.forename: B
authors.initials: B
authors.lastname: Nilsson
authors.forename: M
authors.initials: M
authors.lastname: Olsson
authors.forename: K
authors.initials: K
authors.lastname: Schenck-Gustafsson
mesh_terms: D001646:Bile / Q000737:chemistry; D001659:Biliary Tract / Q000378:metabolism*; D004077:Digoxin / Q000493:pharmacokinetics* / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008297:Male; D014700:Verapamil / Q000097:blood / Q000494:pharmacology*
chemical_list: D004077:Digoxin; D014700:Verapamil