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Drug Interactions

Food-Drug Interactions Precipitated by Fruit Juices other than Grapefruit Juice: An Update Review.

Posted: September 4, 2018
Authors: Chen M; Zhou SY; Fabriaga E; Zhang PH; Zhou Q.
Journal: Journal of Food & Drug Analysis. 26(2S):S61-S71

Abstract: 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.

Oral Pharmacokinetic Interaction of Ester Rich Fruit Juices and Pharmaceutical Excipients with Tenofovir Disoproxil Fumarate in Male Wistar Rats.

Posted: August 15, 2017
Authors: Shailender J; Ravi PR; Saha P; Myneni S.
Journal: Xenobiotica http://dx.doi.org/10.1080/00498254.2016.1269375

Abstract: 1. The aim of this study was to evaluate the role of intestinal esterases on the absorption process of tenofovir disoproxil fumarate (TDF). 2. The esterase inhibition capacity of fruit juices (FJs) rich in ester linkages and pharmaceutical excipients (having ester bonds) was performed in vitro by incubating TDF with each FJ and excipient in the intestinal washings. The ex vivo everted gut sac model was also used to evaluate the absorption enhancement capacity of these FJs and excipients. Single-dose oral pharmacokinetic studies were performed by concomitant administration of TDF with each of the selected FJs and excipients. 3. The in vitro and ex vivo studies showed that cremophor-EL and all FJs prevented the metabolism of TDF with grapefruit juice (GFJ) having the highest level of inhibition. Further, the permeability flux of the monoester form of tenofovir was increased by 113% and 212% by cranberry juice (CBJ) and GFJ, respectively. The in vivo studies also showed that both CBJ and GFJ enhanced the oral bioavailability of TDF as the AUC was increased by 24% and 97%, respectively. 4. These results indicate that the prevention of the metabolic conversion of TDF to its monoester form is crucial in increasing the oral absorption of TDF.

Inhibitory Effect of Six Herbal Extracts on CYP2C8 Enzyme Activity in Human Liver Microsomes.

Posted: March 23, 2016
Authors: Albassam AA, Mohamed ME, Frye RF
Journal: Xenobiotica 45(5):406-12

Abstract: 1. Herbal supplements widely used in the US were screened for the potential to inhibit CYP2C8 activity in human liver microsomes. The herbal extracts screened were garlic, echinacea, saw palmetto, valerian, black cohosh and cranberry. N-desethylamodiaquine (DEAQ) and hydroxypioglitazone metabolite formation were used as indices of CYP2C8 activity. 2. All herbal extracts showed inhibition of CYP2C8 activity for at least one of three concentrations tested. A volume per dose index (VDI) was calculated to determine the volume in which a dose should be diluted to obtain IC50 equivalent concentration. Cranberry and saw palmetto had a VDI value > 5.0 l per dose unit, suggesting a potential for interaction. 3. Inhibition curves were constructed and the IC50 (mean +/- SE) values were 24.7 +/- 2.7 mug/ml for cranberry and 15.4 +/- 1.7 mug/ml for saw palmetto. 4. The results suggest a potential for cranberry or saw palmetto extracts to inhibit CYP2C8 activity. Clinical studies are needed to evaluate the significance of this interaction.

Cranberry proanthocyanidins have anti-biofilm properties against Pseudomonas aeruginosa.

Posted: April 1, 2015
Authors: Ulrey RK, Barksdale SM, Zhou W, van Hoek ML
Journal: BMC Complement Altern Med 14:499.

Abstract: BACKGROUND: Bacteria within a biofilm are phenotypically more resistant to antibiotics, desiccation, and the host immune system, making it an important virulence factor for many microbes. Cranberry juice has long been used to prevent
infections of the urinary tract, which are often related to biofilm formation. Recent studies have found that the A-type proanthocyanidins from cranberries have anti-biofilm properties against Escherichia coli.
METHODS: Using crystal violet biofilm staining, resazurin metabolism assays, and confocal imaging, we examined the ability of A-type proanthocyanidins (PACs) to disrupt the biofilm formation of Pseudomonas aeruginosa. We used mass spectrometry to analyze the proteomic effects of PAC treatment. We also performed synergy assays and in vitro and in vivo infections to determine whether PACs, alone and in combination with gentamicin, could contribute to the killing of P. aeruginosa and the survival of cell lines and G. mellonella. RESULTS: Cranberry PACs reduced P. aeruginosa swarming motility. Cranberry PACs significantly disrupted the biofilm formation of P. aeruginosa. Proteomics analysis revealed significantly different proteins expressed following PAC treatment. In addition, we found that PACs potentiated the antibiotic activity of gentamicin in an in vivo model of infection using G. mellonella. CONCLUSIONS: Results suggest that A-type proanthocyanidins may be a useful therapeutic against the biofilm-mediated infections caused by P. aeruginosa and
should be further tested.

Effect of standardized cranberry extract on the activity and expression of selected biotransformation enzymes in rat liver and intestine.

Posted: April 1, 2015
Authors: Bártíková H, Boušová I, Jedličková P, Lněničková K, Skálová L, Szotáková B
Journal: Molecules 19(9):14948-60.

Abstract: The use of dietary supplements containing cranberry extract is a common way to prevent urinary tract infections. As consumption of these supplements containing a mixture of concentrated anthocyanins and proanthocyanidins has increased, interest in their possible interactions with drug-metabolizing enzymes has grown. In this in vivo study, rats were treated with a standardized cranberry extract
(CystiCran®) obtained from Vaccinium macrocarpon in two dosage schemes (14 days, 0.5 mg of proanthocyanidins/kg/day; 1 day, 1.5 mg of proanthocyanidins/kg/day). The aim of this study was to evaluate the effect of anthocyanins and proanthocyanidins contained in this extract on the activity and expression of
intestinal and hepatic biotransformation enzymes: cytochrome P450 (CYP1A1, CYP1A2, CYP2B and CYP3A), carbonyl reductase 1 (CBR1), glutathione-S-transferase (GST) and UDP-glucuronosyl transferase (UGT). Administration of cranberry extract led to moderate increases in the activities of hepatic CYP3A (by 34%), CYP1A1 (by 38%), UGT (by 40%), CBR1 (by 17%) and GST (by 13%), while activities of these enzymes in the small intestine were unchanged. No changes in the relative amounts of these proteins were found. Taken together, the interactions of cranberry extract with simultaneously administered drugs seem not to be serious.

Evaluation of the in vitro/in vivo potential of five berries (bilberry, blueberry, cranberry, elderberry, and raspberry ketones) commonly used as herbal supplements to inhibit uridine diphospho-glucuronosyltransferase.

Posted: April 1, 2015
Authors: Choi EJ, Park JB, Yoon KD, Bae SK
Journal: Food Chem Toxicol 72:13-9.

Abstract: In this study, we evaluated inhibitory potentials of popularly-consumed berries (bilberry, blueberry, cranberry, elderberry, and raspberry ketones) as herbal supplements on UGT1A1, UGT1A4, UGT1A6, UGT1A9, and UGT2B7 in vitro. We also
investigated the potential herb-drug interaction via UGT1A1 inhibition by blueberry in vivo. We demonstrated that these berries had only weak inhibitory effects on the five UGTs. Bilberry and elderberry had no apparent inhibitions. Blueberry weakly inhibited UGT1A1 with an IC50 value of 62.4±4.40 μg/mL and a Ki value of 53.1 μg/mL. Blueberry also weakly inhibited UGT2B7 with an IC50 value of 147±11.1 μg/mL. In addition, cranberry weakly inhibited UGT1A9 activity (IC50=458±49.7 μg/mL) and raspberry ketones weakly inhibited UGT2B7 activity (IC50=248±28.2 μg/mL). Among tested berries, blueberry showed the lowest IC50 value in the inhibition of UGT1A1 in vitro. However, the co-administration of blueberry had no effect on the pharmacokinetics of irinotecan and its active metabolite, SN-38, which was mainly eliminated via UGT1A1, in vivo. Our data suggests that these five berries are unlikely to cause clinically significant herb-drug interactions mediated via inhibition of UGT enzymes involved in drug metabolism. These findings should enable an understanding of herb-drug interactions for the safe use of popularly-consumed berries.

Can cranberry extract and vitamin C + Zn supplements affect the in vivo activity of paraoxonase 1, antioxidant potential, and lipid status?.

Posted: February 15, 2014
Authors: Begcevic I, Simundic AM, Nikolac N, Dobrijevic S, Rajkovic MG, Tesija-Kuna A
Journal: Clin Lab 59(9-10):1053-60

Abstract: BACKGROUND: The modern way of life exposes us to substantial oxidative stress, putting the focus on the research of antioxidant effects of dietary supplements. Recent studies have shown that the effectiveness of particular vitamins and herbal preparations might have an effect on paraoxonase activity. Paraoxonase 1 is an HDL associated enzyme which prevents the oxidation of LDL. Several studies have shown the beneficial effect of some dietary components to the activity of paraoxonase. The aim of this study was to analyze the effects of cranberry extract and vitamin C and zinc preparations (vitamin C + Zn) on serum paraoxonase 1 activity, antioxidant status, and glucose and lipid concentration.

METHODS: The study included 31 healthy volunteers (median age 24 years). They were divided into 3 groups according to the intervention type and smoking status and exposed to commercially available preparations of the cranberry extract (2 g/day) and vitamin C + Zn (300 mg/day) during 4 weeks.

RESULTS: The results have shown that there is a significant increase in the activity of the paraoxonase 1 in nonsmokers after the intervention with the cranberry extract as well as with vitamin C + Zn preparations. Also, total antioxidant status increased in the non-smokers subgroup after intervention with vitamin C + Zn. However, the lipid profile did not change significantly in response to antioxidant preparations.

CONCLUSIONS: Our results show that antioxidant supplements can increase the antioxidant potential of an organism as well as paraoxonase 1 activity. This observation is pointing to the potential complementary role of dietary supplements in the primary prevention of atherosclerosis.

Cranberry juice ingestion and clinical drug-drug interaction potentials; review of case studies and perspectives.

Posted: February 15, 2014
Authors: Srinivas NR
Journal: J Pharm Pharm Sci 16(2):289-303

Abstract: Cranberry juice is a popular beverage with many health benefits. It has anthocyanins to supplement dietary needs. Based on in vitro evidence cranberry juice is an inhibitor of CYP enzymes and at higher amounts as potent as ketoconazole (CYP3A) and fluconazole (CYP2C9). There is, however, a discrepancy between in vitro and in vivo observations with respect to a number of substrates (cyclosporine, warfarin, flurbiprofen, tizanidine, diclofenac, amoxicillin, ceflacor); with the exception of a single report on midazolam, where there was a moderate increase in the AUC of midazolam in subjects pre-treated with cranberry juice. However, another study questions the clinical relevancy of in vivo pharmacokinetic interaction between cranberry juice and midazolam. The controversy may be due to a) under in vitro conditions all anthocyanin principles may be available to have a concerted effort in CYP inhibition; however, limited anthocyanin principles may be bioavailable with varying low levels in the in vivo studies; b) a faster clearance of the active anthocyanin principles under in vivo conditions may occur, leading to low threshold levels for CYP inhibition; c) efficient protein binding and/or rapid tissue uptake of the substrate may have precluded the drug availability to the enzymes in the in vivo studies. With respect to pharmacodynamic aspects, while the debate continues on the issue of an interaction between warfarin and cranberry juice, the summation of the pharmacodynamics data obtained in patients and healthy subjects from different prospectively designed and controlled clinical trials does not provide overwhelming support for the existence of a pharmacodynamic drug interaction for normal cranberry juice ingestion. However, it is apparent that consumption of large quantities of cranberry juice (about 1-2 L per day) or cranberry juice concentrates in supplements for an extended time period (>3-4 weeks) may temporally alter the effect of warfarin. Therefore, the total avoidance of cranberry juice by warfarin users may not be warranted by the published studies. However, in certain situations of higher intake of cranberry juice or concentrate there may be a need to monitor both warfarin doses and its effect.

Effects of anthocyanins on the AhR-CYP1A1 signaling pathway in human hepatocytes and human cancer cell lines.

Posted: September 15, 2013
Authors: Kamenickova A, Anzenbacherova E, Pavek P, Soshilov AA, Denison MS, Zapletalova M, Anzenbacher P, Dvorak Z
Journal: Toxicol Lett 221(1):1-8

Abstract: Anthocyanins are plant pigments occurring in flowers and berry fruits. Since a phenomenon of food-drug interactions is increasingly emerging, we examined the effects of 21 major anthocyanins and the extracts from 3 food supplements containing anthocyanins on the aryl hydrocarbon receptor (AhR)-cytochrome P450 CYP1A1 signaling pathway in human hepatocytes and human hepatic HepG2 and intestinal LS174T cancer cells. Pelargonidin-3-O-rutinoside (PEL-2) and cyanidin-3,5-O-diglucoside (CYA-3) dose-dependently activated AhR, as revealed by gene reporter assay. PEL-2 and CYA-3 induced CYP1A1 mRNA but not protein in HepG2 and LS174T cells. Neither compounds induced CYP1A1 mRNA and protein in four different primary human hepatocytes cultures. The effects of PEL-2 and CYA-3 on AhR occurred by ligand-dependent and ligand-independent mechanisms, respectively, as demonstrated by ligand binding assay. In a direct enzyme inhibition assay, none of the antocyanins tested inhibited the CYP1A1 marker activity to less than 50% even at 100 μM concentration. PEL-2 and CYA-3 at 100 μM inhibited CYP1A1 to 79% and 65%, respectively. In conclusion, with exception of PEL-2 and CYA-3, there were no effects of 19 major anthocyanins and 3 food supplements containing anthocyanins on AhR-CYP1A1 signaling, implying zero potential of these compounds for food-drug interactions with respect to AhR-CYP1A1 pathway.

Isolation and identification of intestinal CYP3A inhibitors from cranberry (Vaccinium macrocarpon) using human intestinal microsomes

Posted: January 26, 2012
Authors: Kim E, Sy-Cordero A, Graf TN, Brantley SJ, Paine MF, Oberlies NH
Journal: Planta Med. 77(3):265-70

Abstract: infections. These individuals are likely to be taking medications concomitantly with cranberry juice, leading to concern about potential drug-dietary substance interactions, particularly in the intestine, which, along with the liver, is rich in expression of the prominent drug metabolizing enzyme, cytochrome P450 3A (CYP3A). Using a systematic in vitro-in vivo approach, a cranberry juice product was identified recently that elicited a pharmacokinetic interaction with the CYP3A probe substrate midazolam in 16 healthy volunteers. Relative to water, cranberry juice inhibited intestinal first-pass midazolam metabolism. In vitro studies were initiated to identify potential enteric CYP3A inhibitors from cranberry via a bioactivity-directed fractionation approach involving dried whole cranberry [Vaccinium macrocarpon Ait. (Ericaceae)], midazolam, and human intestinal microsomes (HIM). Three triterpenes (maslinic acid, corosolic acid, and ursolic acid) were isolated. The inhibitory potency (IC(50)) of maslinic acid, corosolic acid, and ursolic acid was 7.4, 8.8, and < 10 microM, respectively, using HIM as the enzyme source and 2.8, 4.3, and < 10 microM, respectively, using recombinant CYP3A4 as the enzyme source. These in vitro inhibitory potencies, which are within the range of those reported for two CYP3A inhibitory components in grapefruit juice, suggest that these triterpenes may have contributed to the midazolam-cranberry juice interaction observed in the clinical study.

Warfarin-cranberry juice interaction.

Posted: January 26, 2012
Authors: Hamann GL, Campbell JD, George CM
Journal: Ann Pharmacother. 45(3):e17

Abstract: OBJECTIVE: To report a case of warfarin-cranberry juice interaction, which resulted in an international normalized ratio (INR) elevation on 2 separate occasions.
CASE SUMMARY: A 46-year-old female was receiving a total weekly dose of 56 mg of warfarin. During the 4 months prior to the incident INR, her average INR was 2.0, with a range of 1.6-2.2, while taking the same weekly dose of warfarin. Her INR increased to 4.6 after drinking approximately 1.5 quarts (1420 mL) of cranberry juice cocktail daily for 2 days. Her INR 14 days later without cranberry juice cocktail consumption was 2.3. For the next 3 months, while taking warfarin 56 mg per week, her average INR was 2.1, with a range of 1.4-2.5. At a subsequent visit, after drinking approximately 2 quarts (1893 mL) of cranberry juice cocktail daily for 3-4 days, her INR had increased to 6.5. Her INR after holding warfarin for 3 days was 1.86. Her INR 7 days after resuming the weekly dose of warfarin 56 mg was 3.2. During both of the elevated INR episodes, no other factors were identified that would have resulted in an elevated INR, such as drug, herbal, disease, or other food interactions. An objective causality assessment revealed the interaction was highly probable.
DISCUSSION: Warfarin is the most commonly used anticoagulant for chronic therapy. There have been several case reports of cranberry juice or cranberry sauce potentiating the effects of warfarin by elevating the INR; however, clinical trials evaluating this interaction have failed to demonstrate a significant effect on an INR.
CONCLUSIONS: Our case report describes INR elevations in a patient previously stable on warfarin after ingestion of cranberry juice cocktail daily for several days. This elevation occurred on 2 separate occasions, which distinguishes our case from other published literature.

Cranberry Juice and Warfarin: When Bad Publicity Trumps Science

Posted: January 11, 2011
Authors: Zikria J, Goldman R, Ansell J
Journal: Am J Med 123(5):384-92

Abstract: Based on anecdotal reports, the question of whether cranberry juice interacts with warfarin has been raised. This article discusses the potential mechanism, and systematically reviews case reports as well as clinical trials examining the possible interaction. We systematically searched MEDLINE via PubMed, and the Cochrane Library database. Fifteen case reports were summarized, including the initial unpublished brief reports to the Committee on Safety of Medicines and the subsequent 6 published case reports. Seven clinical trials were analyzed, including 3 studies using warfarin and 4 surrogate drugs. Only 2 cases had a validation scale suggesting a "probable" interaction, but even in these patients there were many reasons to question the validity of a relevant drug interaction. Randomized clinical trials and surrogate markers found no evidence to support the interaction between cranberry juice and warfarin. Because the moderate consumption of cranberry juice does not affect anticoagulation, we encourage the reexamination of initial warnings based on scientific evidence. We conclude that the initial precautionary warnings by administrating bodies are limited to anecdotal case reports and represent misleading conclusions.

Warfarin-herb interactions: a review and study based on assessment of clinical case reports in literature

Posted: January 11, 2011
Authors: Patel JA, Gohil KJ, Garrido G
Journal: BLACPMA 7(2):85-99

Abstract: The potential risk of herb drug interactions is of particular focus today owing to the increasing and inadvertent use of herbs in recent times. It is a major safety concern for the drugs with narrow therapeutic index like warfarin, a most common anticoagulant with the maximum number of interactions reported. The objective of the present study was to conduct a systemic review of literature to consolidate the clinical case reports of warfarin–herb interactions and to assess the report reliabilities. We reviewed the published clinical literature to consolidate and
assess the interactions between various herbs and warfarin, based on reported adverse events, descriptions of the clinical case reports and case series using electronic databases as well as hand picked references from the year 1971 to year 2007 and ranked them on likely causality
using Naranjo’s algorithm. Out of 72 cases of documented case reports of warfarin with various herbs, 84.7% cases were evaluated as possible interactions (61/72) and 15.3% cases (11/72) as probable interactions. Cranberry juice was most commonly involved in interactions with warfarin with 34.7% of cases (25/72) of which 92% cases were possible interactions (23/25) and 8% cases (2/25) were probable
interactions. Hence, we conclude that combining anticoagulant medicines with herbs appears to be a risky proposition. The number of herbs reported to interact with warfarin continues to expand. Patients on warfarin are specifically advised to avoid taking herbal medicines or to
have their INR measured within two weeks of starting the drug, to be on a safer side. Further, more systematic studies pertaining to warfarin herb interactions are urgently warranted.

Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects1

Posted: December 17, 2010
Authors: Abdul MJM, Jiang X, Williams KM, Day RO, Roufogalis BD, Liauw WS, Xu H, McLachlan AJ.
Journal: Br J Pharmacol 154(8):1691-1700

Abstract: Background and purpose: Patients commonly take complementary medicines in conjunction with warfarin yet evidence supporting the safety or the risk of a herb–drug interaction is lacking. The aim of this study was to investigate the possible impact of two commonly used herbal medicines, garlic and cranberry, on the pharmacokinetics and pharmacodynamics of warfarin in healthy male subjects. Experimental approach: An open-label, three-treatment, randomized crossover clinical trial was undertaken and involved 12 healthy male subjects of known CYP2C9 and VKORC1 genotype. A single dose of 25mg warfarin was administered alone or after 2 weeks of pretreatment with either garlic or cranberry. Warfarin enantiomer concentrations, INR, platelet aggregation and clotting factor activity were measured to assess pharmacokinetic and pharmacodynamic interactions between warfarin and herbal medicines. Key results: Cranberry significantly increased the area under the INR–time curve by 30% when administered with warfarin compared with treatment with warfarin alone. Cranberry did not alter S- or R-warfarin pharmacokinetics or plasma protein binding. Co-administration of garlic did not significantly alter warfarin pharmacokinetics or pharmacodynamics. Both herbal medicines showed some evidence of VKORC1 (not CYP2C9) genotype-dependent interactions with warfarin, which is worthy of further investigation.Conclusions and implications: Cranberry alters the pharmacodynamics of warfarin with the potential to increase its effectssignificantly. Co-administration of warfarin and cranberry requires careful monitoring.

Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption.

Posted: November 13, 2010
Authors: Saltzman JR, Kemp JA, Golner BB, Pedrosa MC, Dallal GE, Russell RM
Journal: J Am Coll Nutr 13(6):584-91

Abstract: OBJECTIVE: To investigate the effects of hypochlorhydria and acidic drink ingestion on protein-bound vitamin B12 absorption in elderly subjects.

METHODS: Absorption of protein-bound vitamin B12 was examined in elderly normal subjects (n = 8), and in hypochlorhydric subjects due to omeprazole treatment (n = 8) or with atrophic gastritis (n = 3). Subjects underwent absorption tests of protein-bound vitamin B12 ingested with water, cranberry juice and 0.1 N hydrochloric acid.

RESULTS: Protein-bound vitamin B12 absorption was lower in the omeprazole-treated group (0.50%) compared to the normal group (1.21%; p < 0.001). With cranberry juice ingestion, the omeprazole-treated group showed an increase in absorbed protein-bound vitamin B12 (p = 0.025). With dilute hydrochloric acid ingestion, there was a further increase in vitamin B12 absorption (p < 0.001).

CONCLUSION: Omeprazole causes protein-bound vitamin B12 malabsorption, and ingestion of an acidic drink improves protein-bound vitamin B12 absorption.

Interaction between warfarin and cranberry juice

Posted: November 13, 2010
Authors: Aston JL, Lodolce AE, Shapiro NL
Journal: Pharmacotherapy 26(9):1314-9

Abstract: Warfarin is extensively used for anticoagulation to a target international normalized ratio of 2.0-3.0 for most indications or 2.5-3.5 for high-risk indications; however, many drugs and dietary supplements induce fluctuations in the international normalized ratio. Such fluctuations may lead to therapeutic failure or bleeding complications. Cranberry juice is increasingly used for the prevention and adjunctive treatment of urinary tract infections. The United Kingdom's Committee on Safety of Medicines has alerted clinicians to a potential interaction between warfarin and cranberry juice and has advised that patients avoid their concurrent use. Review and analysis of the literature revealed that ingestion of large volumes of cranberry juice destabilize warfarin therapy. Small amounts of juice are not expected to cause such an interaction. Clinicians should be aware of this potential interaction and monitor and counsel patients accordingly.

Pomelo juice, but not cranberry juice, affects the pharmacokinetics of cyclosporine in humans

Posted: November 11, 2010
Authors: Grenier J, Fradette C, Morelli G, Merritt GJ, Vranderick M, Ducharme MP
Journal: Clin Pharmacol Ther 79(3):255-62

Abstract: BACKGROUND: Cyclosporine (INN, ciclosporin) is a cytochrome P450 (CYP) 3A and P-glycoprotein (P-gp) substrate whose bioavailability increases when administered with grapefruit juice. It is unknown whether pomelo, a closely related citrus fruit, interacts with cyclosporine in humans. In addition, a case study reports that cranberry juice interacts with warfarin, a drug with a narrow therapeutic range. Cranberries have a high content of flavonoids, compounds with various metabolic effects, including interaction with P-gp in vitro. Although the effect of flavonoids is less evident in vivo, cranberry juice has become a very popular beverage, and it was deemed important to investigate whether it has an effect on the disposition of cyclosporine, another drug with a narrow therapeutic range.

METHODS: In an open-label, randomized, 3-way crossover study with a 14-day washout period between each dose, 12 healthy male volunteers received single oral 200-mg doses of cyclosporine according to the following regimens: 200 mg cyclosporine administered with 240 mL of pomelo juice, cranberry juice, or water under fasting conditions. Multiple whole blood samples were collected up to 36 hours after each dose. Concentrations were determined via a liquid chromatography-tandem mass spectrometry method.

RESULTS: Administration of pomelo juice with cyclosporine increased the area under the curve from time 0 to the last measurable concentration (AUCt), area under the curve from time 0 to infinity (AUCinf), and maximum blood concentration (Cmax) of cyclosporine with ratios of least squares means of 119.4% (95% confidence interval [CI], 113.4%-125.8%), 118.9% (95% CI, 113.8%-124.3%), and 112.1% (95% CI, 102.3%-122.8%), respectively. All 3 variables exhibited statistically significant increases (with Bonferroni adjustment), with P = .0001 for AUCt and AUCinf and P = .0167 for Cmax; however, only the increase in AUCt was judged to be clinically significant with a 95% CI outside the 80% to 125% boundaries. Cranberry juice had no clinically significant effect on the overall disposition of cyclosporine. After administration of cyclosporine with cranberry juice, the ratios of least squares means for AUCt, AUCinf, and Cmax for cyclosporine were 95.0% (95% CI, 90.3%-100.1%), 93.4% (95% CI, 89.2%-97.8%), and 95.2% (95% CI, 86.9%-104.2%), respectively.

CONCLUSION: These results suggest that pomelo juice increases the bioavailability of cyclosporine, possibly by inhibiting CYP3A or P-gp activity (or both) in the gut wall. However, drinking a glass of cranberry juice does not appear to significantly influence the disposition of cyclosporine.

Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial

Posted: November 10, 2010
Authors: Zhang L, Ma J, Pan K, Go VL, Chen J, You WC
Journal: Helicobacter 10(2):139-45

Abstract: BACKGROUND: Helicobacter pylori infection is a major cause of peptic ulcer disease and gastric cancer. This study postulated that cranberry juice would be effective in the suppression of H. pylori in an endemically infected population at high risk for gastric cancer.MATERIALS AND METHODS: A prospective, randomized, double-blind, placebo-controlled trial was conducted in Linqu County of Shandong Province, China, where 189 adults aged 48.9 +/- 11.2 years (mean +/- SD) with H. pylori infection were randomly divided into two groups: cranberry juice (n = 97) and placebo (n = 92). Participants were assigned to orally receive two 250-ml juice boxes of cranberry juice or matching placebo beverage daily for 90 days. The degree of H. pylori infection was determined using the 13C-urea breath test before randomization at 35 and 90 days of intervention to assess the efficacy of cranberry juice in alleviating infection.RESULTS: A total of 189 subjects with positive 13C-urea breath test results prior to randomization completed the study. At day 35 of intervention, 14 of the 97 (14.43%) from the the cranberry juice treatment group and 5 of the 92 (5.44%) of the placebo recipients had negative 13C-urea breath test results. After 90 days, the study concluded that 14 of the 97 subjects in the cranberry juice treatment group versus 5 of the 92 in the placebo group yielded negative test results. Eleven individuals from the cranberry juice treatment group and only two from the placebo group were negative at 35 and 90 days of experiment. These results are significant (p < .05).CONCLUSIONS: Regular consumption of cranberry juice can suppress H. pylori infection in endemically afflicted populations.

Cranberry does not affect prothrombin time in male subjects on warfarin.

Posted: November 9, 2010
Authors: Li Z, Seeram NP, Carpenter CL, Thames G, Minutti C, Bowerman S.
Journal: J Am Diet Assoc 106(12):2057-61

Abstract: There have been case reports suggesting that cranberry beverages may interact with warfarin. To date, no research study has been conducted to examine the potential interaction of cranberry and warfarin. The current study is a randomized, placebo-controlled, double-blind, crossover study to investigate the effect of cranberry juice on prothrombin time as assessed by the international normalized ratio (INR). Seven subjects with atrial fibrillation on a stable dose of warfarin for 3 months were randomized to consume 250 mL of cranberry juice for 7 days, then placebo for 7 days, or vice versa. The washout period was 7 days. The prothrombin time/INR was measured at baseline, and on days 2, 4, 7, 10, 14, 16, 18, 21, and 24. Data were analyzed by the Student t test for paired values. The baseline INR was 2.28+/-0.54 for the cranberry group and 2.13+/-0.50 for the placebo group. For all test points, the INR did not change significantly from baseline. At day 7 on cranberry juice, the INR was 2.23+/-0.53 for cranberry first group and 2.16+/-0.40 for placebo first group. The mean differences between the cranberry and placebo groups were not statistically significant. Our results suggest no significant interaction between the daily consumption of 250 mL cranberry juice and warfarin. When counseling patients on dietary changes necessary during warfarin treatment, it does not seem necessary to eliminate daily cranberry juice consumption at amounts of 250 mL, but the INR should be followed up closely.

Effects of daily ingestion of cranberry juice on the pharmacokinetics of warfarin, tizanidine, and midazolam--probes of CYP2C9, CYP1A2, and CYP3A4

Posted: November 9, 2010
Authors: Lilja JJ, Backman JT, Neuvonen PJ
Journal: Clin Pharmacol Ther 81(6):833-9

Abstract: Case reports suggest that cranberry juice can increase the anticoagulant effect of warfarin. We investigated the effects of cranberry juice on R-S-warfarin, tizanidine, and midazolam; probes of CYP2C9, CYP1A2, and CYP3A4. Ten healthy volunteers took 200 ml cranberry juice or water t.i.d. for 10 days. On day 5, they ingested 10 mg racemic R-S-warfarin, 1 mg tizanidine, and 0.5 mg midazolam, with juice or water, followed by monitoring of drug concentrations and thromboplastin time. Cranberry juice did not increase the peak plasma concentration or area under concentration-time curve (AUC) of the probe drugs or their metabolites, but slightly decreased (7%; P=0.051) the AUC of S-warfarin. Cranberry juice did not change the anticoagulant effect of warfarin. Daily ingestion of cranberry juice does not inhibit the activities of CYP2C9, CYP1A2, or CYP3A4. A pharmacokinetic mechanism for the cranberry juice-warfarin interaction seems unlikely.

Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects2

Posted: November 9, 2010
Authors: Mohammed Abdul MI, Jiang X, Williams KM, Day RO, Roufogalis BD, Liauw WS, Xu H, McLachlan AJ
Journal: Br J Pharmacol 154(8):1691-700

Abstract: BACKGROUND AND PURPOSE: Patients commonly take complementary medicines in conjunction with warfarin yet evidence supporting the safety or the risk of a herb-drug interaction is lacking. The aim of this study was to investigate the possible impact of two commonly used herbal medicines, garlic and cranberry, on the pharmacokinetics and pharmacodynamics of warfarin in healthy male subjects.

EXPERIMENTAL APPROACH: An open-label, three-treatment, randomized crossover clinical trial was undertaken and involved 12 healthy male subjects of known CYP2C9 and VKORC1 genotype. A single dose of 25 mg warfarin was administered alone or after 2 weeks of pretreatment with either garlic or cranberry. Warfarin enantiomer concentrations, INR, platelet aggregation and clotting factor activity were measured to assess pharmacokinetic and pharmacodynamic interactions between warfarin and herbal medicines.

KEY RESULTS: Cranberry significantly increased the area under the INR-time curve by 30% when administered with warfarin compared with treatment with warfarin alone. Cranberry did not alter S- or R-warfarin pharmacokinetics or plasma protein binding. Co-administration of garlic did not significantly alter warfarin pharmacokinetics or pharmacodynamics. Both herbal medicines showed some evidence of VKORC1 (not CYP2C9) genotype-dependent interactions with warfarin, which is worthy of further investigation.

CONCLUSIONS AND IMPLICATIONS: Cranberry alters the pharmacodynamics of warfarin with the potential to increase its effects significantly. Co-administration of warfarin and cranberry requires careful monitoring.

Anthocyanins are bioavailable in humans following an acute dose of cranberry juice

Posted: November 8, 2010
Authors: Milbury PE, Vita JA, Blumberg JB
Journal: J Nutr 140(6):1099-1104

Abstract: Research suggests that anthocyanins from berry fruit may affect a variety of physiological responses, including endothelial function, but little information is available regarding the pharmacokinetics of these flavonoids in humans. To determine the pharmacokinetics of cranberry anthocyanins, a study was undertaken in 15 participants (age: 62 +/- 8 y) with coronary artery disease. Blood and urine samples were collected between baseline (0 h) and 4 h after consumption of 480 mL cranberry juice (54% juice; 835 mg total polyphenols; 94.47 mg anthocyanins). Marked inter-individual differences in plasma anthocyanin pharmacokinetics were observed with maximum anthocyanin concentrations detected between 1 and 3 h. Cranberry anthocyanins were bioavailable but with notable differences in the maximum concentration and area under the curve(0-4h) between individual participants. The pattern of anthocyanin glucosides observed in plasma and urine generally reflected the relative concentration determined in the juice. Plasma concentrations of the individual anthocyanins ranged between 0.56 and 4.64 nmol/L. Total recovery of urinary anthocyanin was 0.79 +/- 0.90% of the dose delivered. These data are in agreement with the pharmacokinetics of anthocyanins from other foods suggesting that cranberry anthocyanins are poorly absorbed and rapidly removed from plasma. Observed concentrations of plasma anthocyanins appear insufficient to alter radical load or redox potential but may be adequate to affect signal transduction and/or gene expression.

Interaction potential between cranberry juice and warfarin

Posted: November 8, 2010
Authors: Pham DQ, Pham AQ
Journal: Am J Health Syst Pharm 64(5):490-4

Abstract: PURPOSE: The interaction potential between warfarin and cranberry juice is discussed.

SUMMARY: Reports from the United Kingdom have raised concern over the interaction potential between cranberry juice and warfarin. Warfarin is the most commonly prescribed oral medication for anticoagulation therapy. Cranberry juice is a flavonoid, which has been shown to induce, inhibit, or act as a substrate for the biosynthesis of several cytochrome P-450 (CYP) isoenzymes. Specifically, cranberry juice may inhibit the activity of CYP2C9, the primary isoenzyme involved in the metabolism of S-warfarin. A search of the medical literature identified three peer-reviewed case reports and two peer-reviewed, prospective, randomized, placebo-controlled clinical trials using metabolic surrogates of warfarin (flurbiprofen and cyclosporine) that described possible interactions between cranberry juice and warfarin. Two case reports suggested that cranberry juice increased the International Normalized Ratio (INR) of patients taking warfarin, but neither clearly identified cranberry juice as the sole cause of INR elevation. One case report appeared to show a correlation between the effects of cranberry juice and warfarin metabolism. Both clinical trials indicated the lack of an interaction between cranberry juice and CYP isoenzymes 2C9 and 3A, both of which are necessary in warfarin metabolism. More studies are required to determine the potential interaction between cranberry juice and warfarin.

CONCLUSION: The available data do not seem to show a clinically relevant interaction between cranberry juice and warfarin; however, patients taking warfarin with cranberry juice should be cautioned about the potential interaction and monitored closely for INR changes and signs and symptoms of bleeding.

Effect of high-dose cranberry juice on the pharmacodynamics of warfarin in patients

Posted: November 6, 2010
Authors: Mellen CK, Ford M, Rindone JP
Journal: Br J Clin Pharmacol 70(1):139-42

Abstract: SUBJECT: Case reports suggest an association between cranberry juice and potentiation of warfarin. Studies using 240 ml of cranberry juice daily demonstrated no interaction. It is unknown if higher amounts of cranberry juice will interact with warfarin.

WHAT THIS STUDY ADDS: Cranberry juice at 240 ml twice daily does not alter the pharmacodynamics of warfarin.

AIM: To determine if high-dose cranberry juice (240 ml twice daily) alters the pharmacodynamic action of warfarin.

METHODS: Ten male patients taking stable doses of warfarin were given cranberry juice at 240 ml twice daily for 7 days. Prothrombin times were drawn at baseline and days 2, 6 and 8 after administration of the juice. Prothrombin times were averaged for each day and mean times were compared from each study day to baseline using repeated measures ANOVA.

RESULTS: There was no statistical difference between mean prothrombin time at baseline and any day tested during juice administration.

CONCLUSIONS: Cranberry juice (240 ml twice daily for 1 week) did not alter the pharmacodynamics of warfarin in patients.

Effects of cranberry juice on nifedipine pharmacokinetics in rats

Posted: November 5, 2010
Authors: Uesawa Y, Mohri K
Journal: J Pharm Pharmacol 58(8):1067-72

Abstract: Little information is available about drug interactions with cranberry juice (CJ). Using microsomes from the human liver and rat small intestine, this study was designed to determine whether CJ could inhibit CYP3A-mediated nifedipine (NFP) oxidase activity; it showed that CJ was a potent inhibitor of human and rat CYP3A. Preincubation with 10% vol/vol of CJ and 1 mM NADPH for 10 min resulted in significant inhibition of the NFP oxidation activity of human and rat CYP3A (18.2 and 12.6% decreases, respectively, compared with preincubation experiments without NADPH). In addition, the pharmacokinetic interaction between CJ and NFP in vivo was confirmed in rats. In comparison with a control group, the area under the concentration-time curve (AUC) of NFP was approximately 1.6-fold higher when CJ (2 mL) was injected intraduodenally 30 min before the intraduodenal administration of NFP (30 mg kg(-1)). However, the mean residence time, the volume of distribution and the elimination rate constant were not changed significantly. These data suggest that CJ component(s) inhibit the function of enteric CYP3A. In conclusion, it was found that CJ inhibits the CYP3A-mediated metabolism of NFP in both rats and humans. Furthermore, CJ alters NFP pharmacokinetics in rats.

Enhancing health benefits of berries through phenolic antioxidant enrichment: focus on cranberry.`

Posted: November 5, 2010
Authors: Vattem DA, Ghaedian R, Shetty K
Journal: Asia Pac J Clin Nutr 14(2):120-30

Abstract: Emerging epidemiological evidence is increasingly pointing to the beneficial effects of fruits and vegetables in managing chronic and infectious diseases. These beneficial effects are now suggested to be due to the constituent phenolic phytochemicals having antioxidant activity. Cranberry like other fruits is also rich in phenolic phytochemicals such as phenolic acids, flavonoids and ellagic acid. Consumption of cranberry has been historically been linked to lower incidences of urinary tract infections and has now been shown to have a capacity to inhibit peptic ulcer-associated bacterium, Helicobacter pylori. Isolated compounds from cranberry have also been shown to reduce the risk of cardiovascular diseases. Recent evidence suggests the ability of phytochemical components in whole foods in being more effective in protectively supporting human health than compared to isolated individual phenolic phytochemicals. This implies that the profile of phenolic phytochemicals determines the functionality of the whole food as a result of synergistic interaction of constituent phenolic phytochemicals. Solid state bioprocessing using food grade fungi common in Asian food cultures as well as cranberry phenolic synergies through the addition of functional biphenyls such as ellagic acid and rosmarinic acid along with processed fruit extracts have helped to advance these concepts. These strategies could be further explored to enrich cranberry and cranberry products with functional phytochemicals and further improve their functionality for enhancing health benefits.

Cranberry juice suppressed the diclofenac metabolism by human liver microsomes, but not in healthy human subjects

Posted: November 2, 2010
Authors: Ushijima K, Tsuruoka S, Tsuda H, Hasegawa G, Obi Y, Kaneda T, Takahashi M
Journal: Br J Clin Pharmacol 68(2):194-200

Abstract: AIM: To investigate a potential interaction between cranberry juice and diclofenac, a substrate of CYP2C9.

METHODS: The inhibitory effect of cranberry juice on diclofenac metabolism was determined using human liver microsome assay. Subsequently, we performed a clinical trial in healthy human subjects to determine whether the repeated consumption of cranberry juice changed the diclofenac pharmacokinetics.

RESULTS: Cranberry juice significantly suppressed diclofenac metabolism by human liver microsomes. On the other hand, repeated consumption of cranberry juice did not influence the diclofenac pharmacokinetics in human subjects.

CONCLUSIONS: Cranberry juice inhibited diclofenac metabolism by human liver microsomes, but not in human subjects. Based on the present and previous findings, we think that although cranberry juice inhibits CYP2C9 activity in vitro, it does not change the pharmacokinetics of medications metabolized by CYP2C9 in clinical situations.

Identification of a cranberry juice product that inhibits enteric CYP3A-mediated first-pass metabolism in humans

Posted: November 2, 2010
Authors: Ngo N, Yan Z, Graf TN, Carrizosa DR, Kashuba AD, Dees EC, Oberlies NH, Paine MF.
Journal: Drug Metabol Dispos 37(3):514-22

Abstract: An in vivo study in rats showed a cranberry juice product to inhibit the intestinal first-pass metabolism of the CYP3A substrate nifedipine. However, a clinical study involving the CYP3A probe substrate midazolam and a different cranberry juice product showed no interaction. Because the composition of bioactive components in natural products can vary substantially, a systematic in vitro-in vivo approach was taken to identify a cranberry juice capable of inhibiting enteric CYP3A in humans. First, the effects of five cranberry juices, coded A through E, were evaluated on midazolam 1'-hydroxylation activity in human intestinal microsomes. Juice E was the most potent, ablating activity at 0.5% juice (v/v) relative to control. Second, juice E was fractionated to generate hexane-, chloroform-, butanol-, and aqueous-soluble fractions. The hexane- and chloroform-soluble fractions at 50 microg/ml were the most potent, inhibiting by 77 and 63%, respectively, suggesting that the CYP3A inhibitors reside largely in these more lipophilic fractions. Finally, juice E was evaluated on the oral pharmacokinetics of midazolam in 16 healthy volunteers. Relative to water, juice E significantly increased the geometric mean area under the curve (AUC)(0-infinity) of midazolam by approximately 30% (p=0.001), decreased the geometric mean 1'-hydroxymidazolam/midazolam AUC(0-infinity) ratio by approximately 40% (p<0.001), and had no effect on geometric mean terminal half-life, indicating inhibition of enteric, but not hepatic, CYP3A-mediated first-pass metabolism of midazolam. This approach both showed a potential drug interaction liability with cranberry juice and substantiated that rigorous in vitro characterization of dietary substances is required before initiation of clinical drug-diet interaction studies.

The warfarin-cranberry juice interaction revisited: A systematic in vitro-in vivo evaluation

Posted: November 2, 2010
Authors: Ngo N, Brantley SJ, Carrizosa DR, Kashuba AD, Dees EC, Kroll DJ, Oberlies NH, Paine MF
Journal: J Exp Pharmacol 2010(2):83-91

Abstract: BACKGROUND: Cranberry products have been implicated in several case reports to enhance the anticoagulant effect of warfarin. The mechanism could involve inhibition of the hepatic CYP2C9-mediated metabolic clearance of warfarin by components in cranberry. Because dietary/natural substances vary substantially in bioactive ingredient composition, multiple cranberry products were evaluated in vitro before testing this hypothesis in vivo. METHODS: The inhibitory effects of five types of cranberry juices were compared with those of water on CYP2C9 activity (S-warfarin 7-hydroxylation) in human liver microsomes (HLM). The most potent juice was compared with water on S/R-warfarin pharmacokinetics in 16 healthy participants given a single dose of warfarin 10 mg. RESULTS: Only one juice inhibited S-warfarin 7-hydroxylation in HLM in a concentration-dependent manner (P < 0.05), from 20% to >95% at 0.05% to 0.5% juice (v/v), respectively. However, this juice had no effect on the geometric mean AUC(0-∞) and terminal half-life of S/R-warfarin in human subjects. CONCLUSIONS: A cranberry juice that inhibited warfarin metabolism in HLM had no effect on warfarin clearance in healthy participants. The lack of an in vitro-in vivo concordance likely reflects the fact that the site of warfarin metabolism (liver) is remote from the site of exposure to the inhibitory components in the cranberry juice (intestine).

Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies

Posted: November 1, 2010
Authors: Greenblatt DJ, von Moltke LL, Perloff ES, Luo Y, Harmatz JS, Zinny MA
Journal: Clin Pharmacol Ther 79(1):125-33

Abstract: OBJECTIVES: Recent anecdotal, unvalidated case reports have suggested potentiation of warfarin-induced anticoagulation by cranberry juice, possibly through inhibition of human cytochrome P450 (CYP) 2C9, the enzyme responsible for the clearance of the active S-enantiomer of warfarin. To address this question, the effect of cranberry juice and other beverages on CYP2C9 activity was evaluated in vitro and in vivo.

METHODS: The effects of 4 beverages on CYP2C9 activity were studied in human liver microsomes, by use of flurbiprofen hydroxylation as the index reaction. In a clinical study 14 healthy volunteers received 100 mg flurbiprofen on 5 occasions in a crossover fashion, with at least 1 week separating the 5 trials. Flurbiprofen was preceded in random sequence by the following: (1) cranberry juice placebo (8 oz), (2) cranberry juice (8 oz), (3) brewed tea (8 oz), (4) grape juice (8 oz), and (5) fluconazole, a CYP2C9 inhibitor serving as a positive control, with 8 oz of water.

RESULTS: Flubiprofen hydroxylation in vitro was reduced to 11% +/- 8% of control by 2.5% (vol/vol) brewed tea, to 10% +/- 7% of control by grape juice, to 56% +/- 16% of control by cranberry juice, to 85% +/- 5% of control by cranberry juice placebo, and to 21% +/- 6% of control by the index inhibitor sulfaphenazole (2.5 micromol/L) (P <.01 for all comparisons versus control). Flurbiprofen clearance (29-33 mL/min) and elimination half-life (3.3-3.4 hours) did not differ significantly among trials 1, 2, 3, and 4. However, clearance in the fluconazole treatment condition (trial 5) was significantly reduced compared with the placebo control (17 +/- 5 mL/min versus 31 +/- 8 mL/min, P <.05), and the half-life was prolonged (5.3 +/- 1.6 hours versus 3.3 +/- 0.8 hours, P <.05). Formation of 4-hydroxyflurbiprofen was correspondingly reduced by fluconazole (P <.05).

CONCLUSIONS: Although grape juice and tea impaired CYP2C9 activity in vitro, none of the 3 beverages altered CYP2C9-mediated clearance of flurbiprofen in humans, making a pharmacokinetic interaction with warfarin highly unlikely.

The absence of an interaction between warfarin and cranberry juice: a randomized, double-blind trial.

Posted: October 19, 2010
Authors: Ansell J, McDonough M, Zhao Y, Harmatz JS, Greenblatt DJ.
Journal: J Clin Pharmacol 49(7):824-30

Abstract: The question of potentiation of warfarin anticoagulation by cranberry juice (CJ) is a topic of biomedical importance. Anecdotal reports of CJ-warfarin interaction are largely unconfirmed in controlled studies. Thirty patients on stable warfarin anticoagulation (international normalized ratio [INR], 1.7-3.3) were randomized to receive 240 mL of CJ or 240 mL of placebo beverage, matched for color and taste, once daily for 2 weeks. The INR values and plasma levels of R- and S-warfarin were measured during the 2-week period and a 1-week follow-up period. The CJ and placebo groups (n=14 and 16, respectively) did not differ significantly in mean plasma R- and S-warfarin concentrations. Eight patients (4 on CJ, 4 on placebo) developed minimally elevated INR (range, 3.38-4.52) during the treatment period. Mean INR differed significantly (P<.02) only on treatment day 12; at all other time points, the groups did not differ. Cranberry juice has no effect on plasma S- or R-warfarin plasma levels, excluding a pharmacokinetic interaction. A small though statistically significant pharmacodynamic enhancement of INR by CJ at a single time point is unlikely to be clinically important and may be a random change. Enhanced warfarin anticoagulation attributed to CJ in anecdotal reports may represent a chance temporal association.

Effects of Cranberry Juice on Pharmacokinetics of -Lactam

Posted: October 13, 2010
Authors: Li M, Andrew MA, Wang J, Salinger DH, Vicini P,
Journal: Antimicrob Agents Chemother 53(7):2725-32

Abstract: Cranberry juice consumption is often recommended along with low-dose oral antibiotics for prophylaxis for
recurrent urinary tract infection (UTI). Because multiple membrane transporters are involved in the intestinal
absorption and renal excretion of -lactam antibiotics, we evaluated the potential risk of pharmacokinetic
interactions between cranberry juice and the -lactams amoxicillin (amoxicilline) and cefaclor. The amoxicillin-
cranberry juice interaction was investigated in 18 healthy women who received on four separate occasions
a single oral test dose of amoxicillin at 500 mg and 2 g with or without cranberry juice cocktail (8 oz) according
to a crossover design. A parallel cefaclor-cranberry juice interaction study was also conducted in which 500 mg
cefaclor was administered with or without cranberry juice cocktail (12 oz). Data were analyzed by noncompartmental
methods and nonlinear mixed-effects compartmental modeling. We conclude that the concurrent
use of cranberry juice has no significant effect on the extent of oral absorption or the renal clearance of
amoxicillin and cefaclor. However, delays in the absorption of amoxicillin and cefaclor were observed. These
results suggest that the use of cranberry juice at usual quantities as prophylaxis for UTI is not likely to alter
the pharmacokinetics of these two oral antibiotics.