Recently, a new type of interaction has been reported in which fruit juices diminish oral drug bioavailability through inhibition of organic anion-transporting polypeptide (OATP). In this study, we aimed to clarify the duration of OATP inhibition by grapefruit juice (GFJ), and to compare it with the duration of GFJ-induced inhibition of cytochrome P450 (CYP) 3A4 activity. Seven healthy volunteers were enrolled in this open-label, single-sequence study. They were orally administered celiprolol (100 mg) and midazolam (15 µg/kg) with water on the control day. Three days later, they ingested GFJ (200 mL) 3 times a day for 3 d. On day 1, the same drugs were administered with GFJ. On days 3 and 7, the same drugs were administered with water. Pharmacokinetics of both drugs were evaluated on each trial day. The peak plasma concentration (C max ) and the area under the plasma concentration-time curve from 0 to 8 h (AUC 0-8 ) of celiprolol significantly decreased on day 1, and the mean ratios of these values and the corresponding control-day values were 0.18 and 0.25, respectively. The C max and AUC 0-8 returned to the control levels on days 3 and 7. In contrast, AUC 0-8 of midazolam were higher on days 1 and 3 than on the control day (mean ratio, 2.12 and 1.47, respectively). The AUC 0-8 returned to the control level on day 7. In conclusion, results of this study indicated that the OATP inhibition caused by GFJ dissipated faster than GFJ-mediated alterations in CYP3A4 activity, which were sustained for at least 48 h.Key words organic anion-transporting polypeptide; cytochrome P450; grapefruit juice Food and medication are often taken together. However, certain foods interact with drugs by altering mechanisms that are important determinants of systemic drug availability. In particular, grapefruit juice is known to alter the pharmacokinetics of over 30 prescription drugs by affecting their bioavailability.1-3) The mechanism of this interaction is inhibition of intestinal cytochrome P450 (CYP) 3A4 activity and increased systemic exposure of CYP3A4 substrates. [4][5][6][7][8] In 2012, the United States Food and Drug Administration issued a press release to warn consumers that the intake of grapefruit juice along with medication could cause dangerous side effects.
9)Recently, a new type of interaction has been reported in which fruit juices diminish oral drug bioavailability through inhibition of the organic anion-transporting polypeptide (OATP) uptake transporter, which is a family of membrane solute carrier (SLC) transporters. OATP influences the intestinal absorption of several drugs in clinical use. [10][11][12][13][14] Grapefruit juice decreases the plasma concentrations of some drugs including β-adrenoceptor blocking agents and antihistamines by this mechanism. For example, grapefruit juice was reported to reduce the area under the plasma concentration-time curve (AUC) value for fexofenadine to a mean value of 58% of that when the drug was administered with the corresponding volume of water.10) Furthermore, celiprolol, ...