Co-administration of pazopanib and enteral nutrition with omega-3 fatty acids as a safety issue in a patient treated for metastatic clear cell renal cancer: A case report

Pazopanib is an oral multitargeting tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFRs), approved as the first-line treatment of metastatic renal cell carcinoma (mRCC) and soft tissue sarcoma (STS) at a fixed dose of 800 mg daily taken fasted. Potential drug-meal interactions and adverse events (AEs) may lack recognition and the related data in literature. We report one case of stomatitis/oral mucositis associated with pazopanib administrated with an oral nutritional supplement enriched with omega-3 fatty acids. The 50-year-old patient with mRCC started pazopanib treatment at standard doses of 800 mg daily as first-line therapy for mRCC, and after a few days, he developed stomatitis. Co-administration of pazopanib with high-fat meals could increase the solubility of highly lipophilic pazopanib, increasing its plasma pazopanib area under the curve (AUC), and maximum concentration (Cmax) above optimal therapeutic level can consequently lead to increased frequency/grade of AEs.

Food-drug interactions precipitated by fruit juices other than grapefruit juice: An update review

This review addressed drug interactions precipitated by fruit juices other than grapefruit juice based on randomized controlled trials (RCTs). Literature was identified by searching PubMed, Cochrane Library, Scopus and Web of Science till December 30 2017. Among 46 finally included RCTs, six RCTs simply addressed pharmacodynamic interactions and 33 RCTs studied pharmacokinetic interactions, whereas seven RCTs investigated both pharmacokinetic and pharmacodynamic interactions. Twenty-two juice-drug combinations showed potential clinical relevance. The beneficial combinations included orange juice-ferrous fumarate, lemon juice-^99mTc-tetrofosmin, pomegranate juice-intravenous iron during hemodialysis, cranberry juice-triple therapy medications for H. pylori, blueberry juice-etanercept, lime juice-antimalarials, and wheat grass juice-chemotherapy. The potential adverse interactions included decreased drug bioavailability (apple juice-fexofenadine, atenolol, aliskiren; orange juice-aliskiren, atenolol, celiprolol, montelukast, fluoroquinolones, alendronate; pomelo juice-sildenafil; grape juice-cyclosporine), increased bioavailability (Seville orange juice-felodipine, pomelo juice-cyclosporine, orange-aluminum containing antacids). Unlike furanocoumarin-rich grapefruit juice which could primarily precipitate drug interactions by strong inhibition of cytochrome P450 3A4 isoenzyme and P-glycoprotein and thus cause deadly outcomes due to co-ingestion with some medications, other fruit juices did not precipitate severely detrimental food–drug interaction despite of sporadic case reports. The extent of a juice-drug interaction may be associated with volume of drinking juice, fruit varieties, type of fruit, time between juice drinking and drug intake, genetic polymorphism in the enzymes or transporters and anthropometric variables. Pharmacists and health professionals should properly screen for and educate patients about potential adverse juice-drug interactions and help minimize their occurrence. Much attention should be paid to adolescents and the elderly who ingest medications with drinking fruit juices or consume fresh fruits during drug treatment. Meanwhile, more researches in this interesting issue should be conducted.

Functional identification of organic cation transporter 1 as an atenolol transporter sensitive to flavonoids

Atenolol, a β1-adrenergic receptor blocker, is administered orally and its intestinal absorption has recently been indicated to be mediated by carrier protein and reduced markedly by ingestion of some fruit juices, such as apple and orange juices. This could be postulated to be a problem arising from the interaction of some components of fruit juices with atenolol at a transporter involved in its intestinal uptake, but the responsible transporter and its interacting components have not been identified yet. In an attempt to examine that possibility, we could successfully find that human organic cation transporter 1 (OCT1/SLC22A1), which is suggested to be expressed at the brush border membrane of enterocytes, is highly capable of transporting atenolol. In this attempt, OCT1 was stably expressed in Madin-Darby canine kidney II cells and the specific uptake of atenolol by the transporter was found to be saturable, conforming to the Michaelis-Menten kinetics with the maximum transport rate (V_max) of 4.00 nmol/min/mg protein and the Michaelis constant (K_m) of 3.08 mM. Furthermore, the OCT1-specific uptake was found to be inhibited by various flavonoids, including those contained in fruit juices that have been suggested to interfere with intestinal atenolol absorption. Particularly, phloretin and quercetin, which are major components of apple juice, were potent in inhibiting OCT1-mediated atenolol transport with the inhibition constants of 38.0 and 48.0 µM, respectively. It is also notable that the inhibition by these flavonoids was of the noncompetitive type. These results indicate that OCT1 is an atenolol transporter that may be involved in intestinal atenolol uptake and sensitive to fruit juices, although its physiological and clinical relevance remains to be further examined.

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We explored an atenolol transporter from among the cation or anion transporters.

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OCT1 expressed on apical side in enterocytes has transport activity of atenolol.

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Transport of atenolol by OCT1 is inhibited by flavonoids.

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Phloretin and quercetin noncompetitively inhibit OCT1-mediated atenolol transport.

Relationship between Mediterranean diet and time in therapeutic range in atrial fibrillation patients taking vitamin K antagonists

AIMS

It is unclear if atrial fibrillation (AF) patients treated with oral vitamin K antagonists (VKAs) must follow a specific diet to avoid interference with anticoagulation. The aim of this study was to assess if Mediterranean diet (Med-Diet) may affect quality of anticoagulation, as expressed by the time in therapeutic range (TTR).

METHODS AND RESULTS

A prospective observational study including 553 non-valvular AF patients. Time in therapeutic range was calculated for all patients treated with VKAs, and adherence to Med-Diet was evaluated with a validated nine-item dietary questionnaire. Cardiovascular events (CVEs), such as cardiovascular death and fatal/non-fatal stroke or myocardial infarction, and bleedings were recorded. The median follow-up was 31.6 months. The median number of international normalized ratios for each patient was 63.0 (35.0-98.0) and 38 730 blood samples were analysed. In the whole cohort, the mean TTR was 65.5 ± 17.8%. The mean Med-Diet score was 5.19 ± 1.6, with frequent use of olive oil (90.1%), fruits (88.4%), and vegetables (69.3%) and low meat intake (71.2%). There were no differences among tertiles of Med-Diet score regarding TTR. A multivariable linear regression analysis showed that diabetes (β: -0.105, P = 0.015) and the use of angiotensin converting enzyme inhibitor/angiotensin receptor blockers (β: 0.153, P < 0.001) were associated with TTR. Compared with those without, AF patients with a CVE had significantly lower TTR (65.9 ± 17.9 vs. 59.6 ± 15.9, P = 0.029) and Med-Diet score (5.2 ± 1.5 vs. 4.4 ± 1.9, P = 0.004). A reduction of CVE was observed for each point of the Med-Diet score (hazard ratio 0.790, P = 0.017).

CONCLUSION

In our cohort of AF patients, Med-Diet is not associated with changes in TTR, and thus can be recommended for AF patients who are taking VKAs.

Effects of green tea extract and (-)-epigallocatechin-3-gallate on pharmacokinetics of nadolol in rats

Green tea catechins have been shown to affect the activities of drug transporters in vitro, including P-glycoprotein and organic anion transporting polypeptides. However, it remains unclear whether catechins influence the in vivo disposition of substrate drugs for these transporters. In the present study, we investigated effects of green tea extract (GTE) and (-)-epigallocatechin-3-gallate (EGCG) on pharmacokinetics of a non-selective hydrophilic β-blocker nadolol, which is reported to be a substrate for several drug transporters and is not metabolized by cytochrome P450 enzymes. Male Sprague-Dawley rats received GTE (400 mg/kg), EGCG (150 mg/kg) or saline (control) by oral gavage, 30 min before a single intragastric administration of 10 mg/kg nadolol. Plasma and urinary concentrations of nadolol were determined using high performance liquid chromatography. Pharmacokinetic parameters were estimated by a noncompartmental analysis. Pretreatment with GTE resulted in marked reductions in the maximum concentration (Cmax) and area under the time-plasma concentration curve (AUC) of nadolol by 85% and 74%, respectively, as compared with control. In addition, EGCG alone significantly reduced Cmax and AUC of nadolol. Amounts of nadolol excreted into the urine were decreased by pretreatments with GTE and EGCG, while the terminal half-life of nadolol was not different among groups. These results suggest that the coadministration with green tea catechins, particularly EGCG, causes a significant alteration in the pharmacokinetics of nadolol, possibly through the inhibition of its intestinal absorption mediated by uptake transporters.