Blood pressure-lowering effect of adding grapefruit juice to nifedipine and terazosin in a patient with severe renovascular hypertension

Pisarik, Paul

doi:10.1001/archfami.5.7.413

Cited by 12 publications

(2 citation statements)

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“…It is now evident that a single judicious amount of grapefruit ingested even many hours beforehand has the possibility to affect more than 60 medications. Moreover, adverse event case reports attest to the fact that grapefruit–drug interactions have considerable clinical consequence and scope [30–47]. Warnings are found in many drug product monographs and on a label for application to the prescription vial of affected drugs.…”

Section: Introductionmentioning

confidence: 99%

Fruit juice inhibition of uptake transport: a new type of food–drug interaction

Bailey

2010

Brit J Clinical Pharma

203

133

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A new type of interaction in which fruit juices diminish oral drug bioavailability through inhibition of uptake transport is the focus of this review. The discovery was based on an opposite to anticipated finding when assessing the possibility of grapefruit juice increasing oral fexofenadine bioavailability in humans through inhibition of intestinal MDR1-mediated efflux transport. In follow-up investigations, grapefruit or orange juice at low concentrations potentially and selectively inhibited in vitro OATP1A2-mediated uptake compared with MDR1-caused efflux substrate transport. These juices at high volume dramatically depressed oral fexofenadine bioavailability. Grapefruit was the representative juice to characterize the interaction subsequently. A volume-effect relationship study using a normal juice amount halved average fexofenadine absorption. Individual variability and reproducibility data indicated the clinical interaction involved direct inhibition of intestinal OATP1A2. Naringin was a major causal component suggesting that other flavonoids in fruits and vegetables might also produce the effect. Duration of juice clinical inhibition of fexofenadine absorption lasted more than 2 h but less than 4 h indicating the interaction was avoidable with appropriate interval of time between juice and drug consumption. Grapefruit juice lowered the oral bioavailability of several medications transported by OATP1A2 (acebutolol, celiprolol, fexofenadine, talinolol, L-thyroxine) while orange juice did the same for others (atenolol, celiprolol, ciprofloxacin, fexofenadine). Juice clinical inhibition of OATP2B1 was unresolved while that of OATP1B1 seemed unlikely. The interaction between grapefruit juice and etoposide also seemed relevant. Knowledge of both affected uptake transporter and drug hydrophilicity assisted prediction of the clinical interaction with grapefruit or orange juice. IntroductionDrugs are an essential component of medical therapy. However, the clinical response to them can vary markedly among and within patients and cause adverse effects that result in significant harm in some cases. These unintended and unwanted outcomes often arise when another substance is concomitantly consumed. Food and medication are often taken together. Linking a regular event like food intake with drug administration can improve adherence of the patient to the treatment regimen. However, certain foods can create an interaction through altered activity of a mechanism that is a crucial determinant of systemic drug availability.The bioavailability and clinical effect of a medication can be determined by drug metabolism mediated by a family of oxidizing enzymes known as cytochrome P450s (CYPs) [1][2][3][4]. The specific enzyme, CYP3A4, is particularly significant. It contributes to the inactivation and elimination of an estimated 50% of all drugs. CYP3A4 is located in the simple columnar epithelial cells that line the small intestine and colon (enterocytes) and parenchymal cells that constitute 70-80% of the cytoplasmic mass of t...

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Section: Introductionmentioning

confidence: 99%

Fruit juice inhibition of uptake transport: a new type of food–drug interaction

Bailey

2010

Brit J Clinical Pharma

203

133

View full text Add to dashboard Cite

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“…It reduces repeated dosing of cyclosporine leading to reduction in dose-related side effects and increase patient compliance. Moreover, improvement have been reported in efficacy of antihypertensives and anti-psoriosis therapy by using grapefruit juice as drug sparing agent [53,54]. …”

Section: Resultsmentioning

confidence: 99%