In postmenopausal women receiving long-term GCs, raloxifene is well tolerated and significantly increases spinal and hip BMD after 12 months of treatment.
Background and AimGreen tea and soy products are extensively consumed in daily life. Research has shown that green tea catechins and soy isoflavones may influence the activity of drug metabolizing enzymes and drug transporters. We examined whether regular consumption of green tea extract or soy isoflavones affected the pharmacokinetics of a single dose of rosuvastatin in healthy subjects and whether any interactions were influenced by the polymorphism in the drug transporter ABCG2.Study DesignThis was an open-label, three-phase randomized crossover study with single doses of rosuvastatin.MethodsHealthy Chinese male subjects were given a single dose of rosuvastatin 10 mg on 3 occasions: 1. without herbs; 2. with green tea extract; 3. with soy isoflavone extract. The green tea and soy isoflavone extract were given at a dose containing EGCG 800 mg once daily or soy isoflavones−80 mg once daily for 14 days before statin dosing and at the same time as the statin dosing with at least 4-weeks washout period between phases.ResultsTwenty healthy male subjects completed the study and the intake of green tea extract significantly reduced the systemic exposure to rosuvastatin by about 20% reducing AUC0−24h from [geometric mean (% coefficient of variation)] 108.7 (28.9) h·μg/L to 74.1 (35.3) h·μg/L and Cmax from 13.1 (32.2) μg/L to 7.9 (38.3) μg/L (P < 0.001 for both), without affecting the elimination half-life. The ABCG2 421C>A polymorphism had a significant effect on rosuvastatin exposure but no impact on the interaction with green tea. Soy isoflavones had no significant effect on rosuvastatin pharmacokinetics.ConclusionThis study showed that repeated administration of green tea extract significantly reduced the systemic exposure of rosuvastatin in healthy volunteers. These effects might be predicted to either reduce or increase the lipid-lowering effect of rosuvastatin depending on the mechanism of the effect.
ObjectivesGreen tea and soy products are extensively consumed by many people and they may influence the activity of drug metabolizing enzymes and drug transporters to result in drug interactions. This study was performed to evaluate the effect of green tea and soy isoflavone extracts on the pharmacokinetics of simvastatin in healthy subjects and to clarify the role of polymorphisms in the SLCO1B1 drug transporter in this effect.MethodsThis was an open-label, three-phase randomized crossover pharmacokinetic study. A single dose of simvastatin 20 mg was taken on three occasions (without herbs, with green tea, and with soy isoflavones) by healthy male Chinese subjects. The green tea and soy isoflavone extracts were given at a dose containing EGCG 800 mg once daily or soy isoflavones about 80 mg once daily for 14 days before simvastatin dosing with at least 4-weeks washout period between phases.ResultsAll the 18 subjects completed the study. Intake of soy isoflavones was associated with reduced systemic exposure to simvastatin acid [geometric mean (% coefficient of variation) AUC0–24h from 16.1 (44.2) h⋅μg/L to 12.1 (54.6) h⋅μg/L, P < 0.05) but not the lactone. Further analysis showed that the interaction between simvastatin and the soy isoflavones only resulted in a significant reduction of AUC in subjects with the SLCO1B1 521TT genotype and not in those with the 521C variant allele. There was no overall effect of the green tea extract on simvastatin pharmacokinetics but the group with the SLCO1B1 521TT genotype showed reduced AUC values for simvastatin acid.ConclusionThis study showed repeated administration of soy isoflavones reduced the systemic bioavailability of simvastatin in healthy volunteers that was dependent on the SLCO1B1 genotype which suggested that soy isoflavones-simvastatin interaction is impacted by genotype-related function of this liver uptake transporter.
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