Effect of Grapefruit Juice Volume on the Reduction of Fexofenadine Bioavailability: Possible Role of Organic Anion Transporting Polypeptides*
Bibliographic record
Abstract
OBJECTIVE: The purpose of this study was to elucidate the potential clinical relevance and mechanism(s) of action of 2 different volumes of grapefruit juice on the reduction of bioavailability of fexofenadine, a substrate of organic anion transporting polypeptides. METHODS: Grapefruit juice or water at normal (300 mL) or high (1200 mL) volume was ingested concomitantly with 120 mg fexofenadine by 12 healthy volunteers in a randomized 4-way crossover study, and fexofenadine pharmacokinetics were determined over a period of 8 hours. RESULTS: The 300-mL volume of grapefruit juice decreased the mean area under the plasma drug concentration-time curve (AUC) and the peak plasma drug concentration of fexofenadine to 58% (P < .001) and 53% (P < .001), respectively, of those with the corresponding volume of water, and 1200 mL grapefruit juice reduced these parameters to 36% ( P < .001) and 33% ( P < .001), respectively, of those with the corresponding volume of water. The 300-mL volume of grapefruit juice diminished the AUC of fexofenadine variably among individuals. This decline correlated with baseline AUC of fexofenadine with water at equivalent volume (r(2) = 0.97, P < .0001). The 1200-mL volume of grapefruit juice decreased the AUC of fexofenadine more than the 300-mL volume of grapefruit juice compared with the corresponding volume of water in each subject by a constant amount. Grapefruit juice, 300 mL and 1200 mL, reduced the coefficient of variation of the AUC of fexofenadine by 2-fold compared with that with a matching volume of water. CONCLUSIONS: Grapefruit juice at a commonly consumed volume diminished the oral bioavailability of fexofenadine sufficiently to be pertinent clinically, likely by direct inhibition of uptake by intestinal organic anion transporting polypeptide A (OATP-A; new nomenclature, OATP1A2). A much higher volume caused an additional modest effect, possibly from reduced intestinal concentration and transit time of fexofenadine. This food-drug interaction appears to be novel and may be relevant to other fruit juices and drugs.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".