Volume 43, Issue 6 p. 649-660

Influence of Drugs Interacting with CYP3A4 on the Pharmacokinetics, Pharmacodynamics, and Safety of the Prandial Glucose Regulator Repaglinide

Vibeke Hatorp MSc

Vibeke Hatorp MSc

From the Clinical Development and Drug Metabolism Departments, Novo Nordisk A/S, Bagsvaerd, Denmark.

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Kristian T. Hansen PhD

Kristian T. Hansen PhD

From the Clinical Development and Drug Metabolism Departments, Novo Nordisk A/S, Bagsvaerd, Denmark.

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Mikael S. Thomsen MSc, PhD

Corresponding Author

Mikael S. Thomsen MSc, PhD

From the Clinical Development and Drug Metabolism Departments, Novo Nordisk A/S, Bagsvaerd, Denmark.

Address for reprints: Mikael S. Thomsen, MSc, PhD, Novo Nordisk A/S, Clinical Pharmacology, Clinical Development, Kroegshoejvej 53A, Building 9E, DK-2880 Bagsvaerd, Denmark.Search for more papers by this author
First published: 08 March 2013
Citations: 72

Abstract

The object of this study was to analyze drug interactions between repaglinide, a short-acting insulin secretagogue, and five other drugs interacting with CYP3A4: ketoconazole, rifampicin, ethinyloestradiol/levonorgestrel (in an oral contraceptive), simvastatin, and nifedipine. In two open-label, two-period, randomized crossover studies, healthy subjects received repaglinide alone, repaglinide on day 5 of ketoconazole treatment, or repaglinide on day 7 of rifampicin treatment. In three open-label, three-period, randomized crossover studies, healthy subjects received 5 days of repaglinide alone; 5 days of ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine alone; or 5 days of repaglinide concomitant with ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine. Compared to administration of repaglinide alone, concomitant ketoconazole increased mean AUC0-∞ for repaglinide by 15% and mean Cmax by 7%. Concomitant rifampicin decreased mean AUC0-∞ for repaglinide by 31% and mean Cmax by 26%. Concomitant treatment with CYP3A4 substrates altered mean AUC0–5h and mean Cmax for repaglinide by 1% and 17% (ethinyloestradiol/levonorgestrel), 2% and 27% (simvastatin), or 11% and 3% (nifedipine). Profiles of blood glucose concentration following repaglinide dosing were altered by less than 8% by both ketoconazole and rifampicin. In all five studies, most adverse events were related to hypoglycemia, as expected in a normal population given a blood glucose regulator. The safety profile of repaglinide was not altered by pretreatment with ketoconazole or rifampicin or by coadministration with ethinyloestradiol/levonorgestrel. The incidence of adverse events increased with coadministration of simvastatin or nifedipine compared to either repaglinide or simvastatin/nifedipine treatment alone. No clinically relevant pharmacokinetic interactions occurred between repaglinide and the CYP3A4 substrates ethinyloestradiol/levonorgestrel, simvastatin, or nifedipine. The pharmacokinetic profile of repaglinide was altered by administration of potent inhibitors or inducers, such as ketoconazole or rifampicin, but to a lesser degree than expected. These results are probably explained by the metabolic pathway of repaglinide that involves other enzymes than CYP3A4, reflected to some extent by a small change in repaglinide pharmacodynamics. Thus, careful monitoring of blood glucose in repaglinide-treated patients receiving strong inhibitors or inducers of CYP3A4 is recommended, and an increase in repaglinide dose may be necessary. No safety concerns were observed, except a higher incidence in adverse events in patients receiving repaglinide and simvastatin or nifedipine.