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Effects of Sairei‐to on the pharmacokinetics of nifedipine in rats
Author(s) -
Ikehata Mika,
Ohnishi Noriaki,
Matsumoto Tsuyoshi,
Kiyohara Yoshifumi,
Maeda Atsushi,
Kawakita Takuya,
Takara Kohji,
Yokoyama Teruyoshi
Publication year - 2008
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2234
Subject(s) - pharmacokinetics , cmax , medicine , oral administration , pharmacology , cyp3a , nifedipine , metabolism , cytochrome p450 , calcium
Sairei‐to is a traditional herbal medicine used to complement, and as an alternative to, Western drugs. The aim of this study was to evaluate the pharmacokinetic interactions between Sairei‐to and nifedipine (NFP), a substrate for CYP3A, in rats. NFP‐oxidizing activity and the pharmacokinetics of NFP were examined after a single or 1‐week of administration of Sairei‐to (EK‐114). NFP‐oxidizing activity was enhanced transiently around 24 h after a single administration of EK‐114 (1400 mg/kg). In vivo , the first‐pass metabolism of NFP increased in the small intestine at 24 h after the administration of EK‐114, and this effect disappeared at 72 h. Co‐administration of EK‐114 tended to inhibit the metabolism of NFP. On the other hand, when EK‐114 was given at a high dose (1400 mg/kg) for 1 week, the oxidation of NFP in the small intestine was inhibited, and C max and AUC after the oral administration of NFP increased. In addition, a clinical dose of EK‐114 (140 mg/kg) did not alter the pharmacokinetics of NFP, regardless of the administration schedule. EK‐114 was suggested to affect the metabolism of NFP. However, the CYP3A‐mediated pharmacokinetic interaction on the concomitant use of EK‐114 may not be clinically significant. Copyright © 2007 John Wiley & Sons, Ltd.