Lack of pharmacokinetic interaction between fluvastatin and green tea in healthy volunteers

Modeled Hepatic/Plasma Exposures of Fluvastatin Prescribed Alone in Subjects with Impaired Cytochrome P450 2C9*3 as One of Possible Determinant Factors Likely Associated with Hepatic Toxicity Reported in a Japanese Adverse Event Database

Fluvastatin is a 3-hydroxy-3-methylglutaryl CoA reductase inhibitor that competitively inhibits human cytochrome P450 (P450) 2C9 in vitro. Drug interactions between a variety of P450 2C9 substrates/inhibitors and fluvastatin can increase the incidence of fluvastatin-related hepatic or skeletal muscle toxicity in vivo. In this survey, the prescribed dosage of fluvastatin was reduced or discontinued in 133 of 164 patients receiving fluvastatin alone, as recorded in the Japanese Adverse Drug Event Report database of spontaneously reported events. The median days to onset of fluvastatin-related disorders were in the range 30-35 d in the 87 patients. Therefore, we aimed to focus on fluvastatin and, using the pharmacokinetic modeling technique, estimated the virtual plasma and hepatic exposures in subjects harboring the impaired CYP2C9*3 allele. The plasma concentrations of fluvastatin modeled after a virtual oral 20-mg dose increased in homozygotes with CYP2C9*3; the area under the plasma concentration curve was 4.9-fold higher than that in Japanese homozygotes for wild-type CYP2C9*1. The modeled hepatic concentrations of fluvastatin in patients with CYP2C9*3/*3 after virtual daily 20-mg doses for 7 d were 31-fold higher than those in subjects with CYP2C9*1/*1. However, heterozygous Chinese patients with CYP2C9*1/*3 reportedly have a limited elevation (1.2-fold) in plasma maximum concentrations. Virtual hepatic/plasma exposures in subjects harboring the impaired CYP2C9*3 allele estimated using pharmacokinetic modeling indicate that such exposure could be a causal factor for hepatic disorders induced by fluvastatin prescribed alone in a manner similar to that for interactions with a variety of co-administered drugs.

An Update on Impacts of Epigallocatechin Gallate Co-administration in Modulating Pharmacokinetics of Statins, Calcium Channel Blockers, and Beta-blockers

Brewed green tea, green tea extract, and its primary active compound, epigallocatechin gallate, may interact with drugs and alter the drug's therapeutic effectiveness, ultimately leading to therapeutic failure or drug overdose. Several isolated reports have claimed that epigallocatechin gallate is the main active ingredient that causes these effects. While a few studies aimed to uncover evidence of epigallocatechin gallate-drug interactions, no study has thoroughly and collectively reviewed them. Epigallocatechin gallate is a potential cardioprotective agent used by many patients with cardiovascular diseases as a complementary medicine alongside conventional modern medications, either with or without the knowledge of their physicians. Therefore, this review focuses on the impact of concurrent epigallocatechin gallate supplementation on pharmacokinetics and pharmacodynamics of several commonly used cardiovascular drugs (statins, beta-blockers, and calcium channel blockers). The PubMed index was searched for key words related to this review, without year limit, and the results were analyzed for interactions of cardiovascular drugs with epigallocatechin gallate. This review concludes that epigallocatechin gallate increases systemic circulation of several statins (simvastatin, fluvastatin, rosuvastatin) and calcium channel blockers (verapamil), but decreases the bioavailability of beta-blockers (nadolol, atenolol, bisoprolol). Further studies on its clinical significance in affecting drug efficacy are required.

Epigallocatechin-3-Gallate Therapeutic Potential in Cancer: Mechanism of Action and Clinical Implications

Cellular signaling pathways involved in the maintenance of the equilibrium between cell proliferation and apoptosis have emerged as rational targets that can be exploited in the prevention and treatment of cancer. Epigallocatechin-3-gallate (EGCG) is the most abundant phenolic compound found in green tea. It has been shown to regulate multiple crucial cellular signaling pathways, including those mediated by EGFR, JAK-STAT, MAPKs, NF-κB, PI3K-AKT-mTOR, and others. Deregulation of the abovementioned pathways is involved in the pathophysiology of cancer. It has been demonstrated that EGCG may exert anti-proliferative, anti-inflammatory, and apoptosis-inducing effects or induce epigenetic changes. Furthermore, preclinical and clinical studies suggest that EGCG may be used in the treatment of numerous disorders, including cancer. This review aims to summarize the existing knowledge regarding the biological properties of EGCG, especially in the context of cancer treatment and prophylaxis.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Effects of single green tea ingestion on pharmacokinetics of nadolol in healthy volunteers

AIMS

The aim of this study was to investigate the effects of a single green tea (GT), administered concomitantly or 1 hour before nadolol intake on nadolol pharmacokinetics.

METHODS

In a randomized 3-phase crossover study, 11 healthy volunteers received an oral administration of nadolol with, or 1 hour after preingestion of brewed GT, or with water in a volume of 150 mL.

RESULTS

Geometric mean ratio with 90% confidence interval for nadolol AUC_0-48 was 0.371 (0.303-0.439) with concomitant GT. In addition, ingestion of GT 1 hour before nadolol administration resulted in a significant reduction of nadolol AUC_0-48 with geometric mean ratio of 0.536 (0.406-0.665). There were no differences in time to maximal plasma concentration and renal clearance of nadolol among groups.

CONCLUSION

These results suggest that single concomitant ingestion of GT substantially decreases plasma concentrations of nadolol. Moreover, the reduction in nadolol bioavailability could persist for at least 1 hour after drinking a cup of GT.

Effects of Green Tea Extract on Atorvastatin Pharmacokinetics in Healthy Volunteers

BACKGROUND AND OBJECTIVES

Green tea catechins were recently reported to inhibit drug transporters such as organic anion-transporting polypeptides (OATPs) and metabolic enzymes, affecting the bioavailability of many drugs. This study aimed to evaluate the clinical significance of the effects of different doses of green tea extract on the pharmacokinetic parameters of atorvastatin and to rationalize the associated interaction mechanism.

METHODS

A randomized, double-blind, three-phase crossover study involving 12 healthy volunteers was performed. Participants received a single dose of atorvastatin 40 mg alone (control group), atorvastatin 40 mg plus a capsule containing 300 mg of dry green tea extract, or atorvastatin 40 mg plus a capsule containing 600 mg of dry green tea extract. Plasma samples taken from the volunteers were analyzed for atorvastatin using liquid chromatography-tandom mass spectrometry (LC/MS/MS).

RESULTS

Compared to atorvastatin alone, the administration of 300 mg or 600 mg of the green tea extract along with atorvastatin decreased the peak plasma concentration (C_max) of atorvastatin by 25% and 24%, respectively (P < 0.05), and the area under the plasma concentration-time curve (AUC_0-∞) of atorvastatin by 24% and 22%, respectively (P < 0.05). Additionally, administration of 300 mg or 600 mg of the green tea extract increased the apparent oral clearance (CL/F) of atorvastatin by 31% and 29%, respectively. The time to C_max (T_max) and the elimination half-life (t_1/2) of atorvastatin did not differ among the three phases. The effects of 600 mg of the green tea extract on the pharmacokinetic parameters of atorvastatin were not significantly different from the effects of 300 mg of the green tea extract.

CONCLUSION

Green tea extract decreases the absorption but not the elimination of atorvastatin, possibly by inhibiting OATP, albeit not in a dose-dependent manner. Coadministration of green tea extract with atorvastatin may necessitate the monitoring of the plasma concentration of atorvastatin in clinical practice.