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Yamamoto T, Furihata K, Hisaka A, Moritoyo T, Ogoe K, Kusayama S, Motohashi K, Mori A, Iwatsubo T, Suzuki H. Notable Drug-Drug Interaction Between Etizolam and Itraconazole in Poor Metabolizers of Cytochrome P450 2C19. J Clin Pharmacol 2017; 57:1491-1499. [PMID: 28679023 DOI: 10.1002/jcph.956] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/08/2017] [Indexed: 01/16/2023]
Abstract
In this study, impact of a polymorphism of CYP2C19 on drug-drug interaction (DDI) was examined for etizolam. The effect of itraconazole (a strong CYP3A inhibitor) on the pharmacokinetics of etizolam (a substrate of CYP2C19 and CYP3A) was assessed in both extensive metabolizers (EMs) and poor metabolizers (PMs) of CYP2C19. Sixteen participants (8 EMs and 8 PMs) received a single oral dose of etizolam (0.25 mg) on day 1. The participants ingested itraconazole (200 mg twice a day) on days 2-5. On day 5, participants received an oral dose of etizolam (0.25 mg) again. Before coadministration of itraconazole (day 1), the area under the time-plasma concentration curve from time zero to infinity (AUC∞ ) of etizolam was higher in PMs than in EMs (2.65-fold, P < .01). Coadministration of itraconazole increased the AUC∞ of etizolam 1.66-fold and 2.34-fold in EMs and PMs, respectively (day 5). Consequently, AUC∞ was 6.18-fold higher in PMs with itraconazole than that in EMs without itraconazole. The increase by itraconazole was larger in PMs (P < .01). In heterozygous EMs (hEMs), AUC∞ was simulated to be 2.56-fold higher with itraconazole than that in EMs without itraconazole. We found that in vitro measurements of fraction metabolized (fm ) using the liver microsome prepared from PM donors would be helpful to predict polymorphism-dependent DDIs. These results suggest that the PMs and hEMs of a polymorphic CYP would be at higher risk of DDIs relative to EMs for drugs metabolized by both polymorphic and nonpolymorphic CYPs such as etizolam.
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Affiliation(s)
- Takehito Yamamoto
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Kenichi Furihata
- P-One Clinic, Keikokai Medical Corporation, Tokyo, Japan.,Department of Clinical Pharmacology, Tokai University School of Medicine, Kanagawa, Japan
| | - Akihiro Hisaka
- Pharmacology and Pharmacokinetics, The University of Tokyo Hospital.,Present affiliation: Clinical Pharmacology and Pharmacometrics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Takashi Moritoyo
- Department of Clinical Research Governance, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazuaki Ogoe
- P-One Clinic, Keikokai Medical Corporation, Tokyo, Japan
| | | | - Keiju Motohashi
- Unit for Early and Exploratory Clinical Department, The University of Tokyo Hospital, Tokyo, Japan
| | - Akiko Mori
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Takeshi Iwatsubo
- Unit for Early and Exploratory Clinical Department, The University of Tokyo Hospital, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
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