1. Effect of lapatinib on oral digoxin absorption in patients.
- Author
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Koch KM, Smith DA, Botbyl J, Arya N, Briley LP, Cartee L, White JH, Beyer J, Dar MM, Chung HC, Chu Q, and Bang YJ
- Subjects
- ATP Binding Cassette Transporter, Subfamily B antagonists & inhibitors, ATP Binding Cassette Transporter, Subfamily B metabolism, Administration, Oral, Adult, Alberta, Antineoplastic Agents adverse effects, Area Under Curve, Breast Neoplasms blood, Cardiotonic Agents adverse effects, Cardiotonic Agents blood, Cardiotonic Agents pharmacokinetics, Cross-Over Studies, Digoxin adverse effects, Digoxin blood, Drug Interactions, Female, Half-Life, Humans, Lapatinib, Metabolic Clearance Rate, Middle Aged, Protein Kinase Inhibitors adverse effects, Quinazolines adverse effects, Risk Assessment, Seoul, Antineoplastic Agents administration & dosage, Breast Neoplasms drug therapy, Cardiotonic Agents administration & dosage, Digoxin administration & dosage, Digoxin pharmacokinetics, Gastrointestinal Absorption drug effects, Protein Kinase Inhibitors administration & dosage, Quinazolines administration & dosage
- Abstract
The potential for an interaction between lapatinib and absorption of the P-glycoprotein (ABCB1) substrate digoxin at a therapeutic dose in breast cancer patients was characterized. Seventeen women with HER2-positive metastatic breast cancer received a single oral 0.5-mg dose of digoxin on days 1 and 9 and oral lapatinib 1500 mg once daily on days 2 through 9. Digoxin pharmacokinetic parameters were determined on day 1 (digoxin administration alone) and on day 9 (coadministration of lapatinib and digoxin), and parameters were compared to determine the effects of lapatinib on digoxin absorption. Concomitant medications that could affect ABCB1 were accounted for. Lapatinib 1500 mg/day increased digoxin absorption approximately 80%, implicating lapatinib inhibition of intestinal ABCB1-mediated efflux. In summary, coadministration of lapatinib with narrow therapeutic index drugs that are substrates of ABCB1 should be undertaken with caution and dose adjustment should be considered., (© 2015, The American College of Clinical Pharmacology.)
- Published
- 2015
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