Simvastatin In Healthy Subjects Research Articles

Effects of Soy Isoflavones and Green Tea Extract on Simvastatin Pharmacokinetics and Influence of the SLCO1B1 521T > C Polymorphism.

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.

Effect of Cilostazol on the Pharmacokinetics of Simvastatin in Healthy Subjects.

Purpose We evaluated potential drug-drug interactions between cilostazol and simvastatin, both CYP3A substrates, in healthy subjects. Methods An open-label, two-period, fixed-sequence clinical study was conducted. Seventeen subjects were given a single oral dose of simvastatin 40 mg on day 1 and multiple oral doses of cilostazol 100 mg twice daily on days 2 to 5 followed by a single dose of cilostazol and simvastatin on day 6. Plasma concentrations of simvastatin and its active metabolite, simvastatin acid, were measured using liquid chromatography-tandem mass spectrometry for pharmacokinetic assessment. Moreover, serum lipid profiles under fasting conditions were determined. Results The geometric mean ratios of the area under the plasma concentration-time curve from time zero to time infinity of simvastatin combined with cilostazol to that of simvastatin alone were 1.64 (90% CI, 1.38-1.95) for simvastatin and 1.31 (1.04-1.66) for simvastatin acid. In addition, coadministration with cilostazol significantly increased the maximum concentration of simvastatin and simvastatin acid, up to 1.8-fold and 1.6-fold, respectively. However, the effects of a single dose of simvastatin on serum lipid profiles were not affected notably when simvastatin was coadministered with cilostazol. Conclusions Multiple doses of cilostazol increased the systemic exposure of simvastatin and simvastatin acid following a single dose of simvastatin.

Effects of Extended-Release Niacin and Extended-Release Niacin/Laropiprant on the Pharmacokinetics of Simvastatin in Healthy Subjects

The use of multiple lipid-modifying agents with different mechanisms of action is often required to regulate lipid levels in patients with dyslipidemia. During combination therapy, alterations in the pharmacokinetics of any of the drugs used and their metabolites may occur. Three separate open-label, randomized, crossover studies evaluated the potential for pharmacokinetic interaction between extended-release niacin (with and without concomitant laropiprant) and simvastatin in healthy subjects. Study 1 used single doses of extended-release niacin and simvastatin; study 2 used multiple-dose coadministration of extended-release niacin/laropiprant and simvastatin in healthy subjects; and study 3 used single doses of both extended-release niacin and the coadministration of extended-release niacin/laropiprant and simvastatin in healthy Chinese subjects. During each treatment period, plasma samples were collected predose and at prespecified postdose time points for pharmacokinetic analyses. The safety and tolerability of simvastatin with and without coadministered extended-release niacin (or extended-release niacin/laropiprant) were assessed by clinical evaluation of adverse experiences. In 2 studies in healthy subjects, modest increases in exposure to simvastatin acid (by ∼60%) by extended-release niacin and extended-release niacin/laropiprant were observed. Based on the clinical experience with simvastatin, these effects are not believed to be clinically meaningful. In the third study on healthy Chinese subjects, no statistically meaningful increases in exposure to simvastatin by extended-release niacin and extended-release niacin/laropiprant were observed. In all populations examined in these studies, the coadministration of extended-release niacin and simvastatin was generally well tolerated.

Pomegranate juice does not affect the disposition of simvastatin in healthy subjects.

Previous in vitro and in vivo investigations reported controversial results for the inhibitory potential of pomegranate on Cytochrome P450 (CYP) 3A activity. This study evaluated the effect of pomegranate juice on the disposition of simvastatin, a CYP3A4 substrate, and simvastatin acid, its active metabolite, compared with grapefruit juice in healthy subjects. A single oral pharmacokinetic study of 40mg simvastatin was conducted as a three-way crossover (control, pomegranate, and grapefruit juices) in 12 healthy male subjects. The subjects took pomegranate or grapefruit juice three times per day for 3days (900mL/day) and on the third day, the pharmacokinetic study was executed. Blood samples were collected to 24h post-dose and the pharmacokinetic parameters of simvastatin and simvastatin acid were compared among the study periods. In the period of grapefruit juice, the mean C max and AUCinf of simvastatin [the geometric mean ratio (90% CI) 15.6 (11.6-21.0) and 9.1 (6.0-13.7)] were increased significantly when compared with the control period, whereas they were not significantly different in the period of pomegranate juice [C max and AUCinf 1.20 (0.89-1.62) and 1.29 (0.85-1.94)]. The mean C max and AUCinf of simvastatin acid were increased significantly after intake of grapefruit juice, but not pomegranate juice. These results suggest that pomegranate juice affects little on the disposition of simvastatin in humans. Pomegranate juice does not seem to have a clinically relevant inhibitory potential on CYP3A4 activity.

Effect of repeated administration of eslicarbazepine acetate on the pharmacokinetics of simvastatin in healthy subjects

To investigate the effect of eslicarbazepine acetate (ESL) on the pharmacokinetics of simvastatin (SMV), a known CYP3A4 substrate, in healthy subjects. Single centre, two-way cross-over, randomized, open-label study in 24 healthy volunteers. The volunteers received an oral single-dose of SMV 80mg on two occasions (once administered alone and once after treatment with an oral once-daily dose of 800mg of ESL for 14 days), separated by a wash-out period of 3 weeks or more. The analysis of variance (ANOVA) was used to test for differences between Test (SMV under co-administration with ESL) and Reference (SMV administered alone) treatments for AUC0-∞, AUC0-t and Cmax of SMV and SMV-acid. Mean systemic exposure (AUC) measurements for both SMV and SMV-β-hydroxyacid (SMV-acid) were up to 54% lower during ESL use. The Test/Reference geometric mean ratios (GMR) (90% CI) for the AUC0-t of SMV and SMV-acid were 46% (38%; 55%) and 49% (44%; 55%), respectively. Mean peak concentrations (Cmax) of both SMV and SMV-acid were reduced by 60% and 41%, respectively, when SMV was administered with ESL. A significant effect of repeated ESL administration on the pharmacokinetics of SMV and its metabolite SMV-acid was observed. Therefore, dose adjustment of SMV may be required when used concomitantly with ESL, if a clinically significant change in lipids is noted.

Evaluation of a pharmacokinetic interaction between valsartan and simvastatin in healthy subjects

ABSTRACTObjective: The potential for a pharmacokinetic drug interaction between valsartan, an antihypertensive drug, and simvastatin, a lipid-lowering agent, was investigated in this study. This was an open-label, multiple-dose, randomized, three-period, cross over study in 18 healthy subjects. Each subject received one 160 mg valsartan tablet or one 40 mg simvastatin tablet or co-administration of valsartan (160 mg) and simvastatin (40 mg) tablets for 7 days, with a 7‑day inter-dose washout period. The steady-state pharmacokinetics of valsartan, simvastatin β‑hydroxy acid (active metabolite of simvastatin) and simvastatin (pro-drug) were determined on day 7 of each dosing period.Results: The results were interpreted based on the point estimates and the 90% confidence intervals.italic> These results indicated that the area under the curve of plasma concentration from 0 to 24 hours (AUC(0–24)) of valsartan, simvastatin β‑hydroxy acid and simvastatin was increased by 14%, 19%, and 23%, respectively, with the combination treatment. In addition, the maximum concentration (Cmax) of valsartan and simvastatin β‑hydroxy acid was increased by 10% and 22%, respectively, and the Cmax of simvastatin was decreased by 26% with the combination treatment. All treatments were safe and well tolerated.Conclusions: Based on the wide therapeutic dosage ranges of valsartan and simvastatin, and the highly variable pharmacokinetics of three analytes, the observed differences in the exposure and Cmax of valsartan, simvastatin β‑hydroxy acid and simvastatin in the combination treatment are unlikely to be of clinical relevance.

Evaluation of the potential for steady-state pharmacokinetic interaction between vildagliptin and simvastatin in healthy subjects

ABSTRACTBackground: Vildagliptin is an orally active, potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4), the enzyme responsible for the degradation of incretin hormones. By enhancing prandial levels of incretin hormones, vildagliptin improves glycemic control in type 2 diabetes. Co-administration of vildagliptin and simvastatin, an HMG-CoA-reductase inhibitor may be required to treat patients with diabetes and dyslipidemia. Therefore, this study was conducted to determine the potential for pharmacokinetic drug–drug interaction between vildagliptin and simvastatin at steady-state.Methods: An open label, single center, multiple dose, three period, crossover study was conducted in 24 healthy subjects. All subjects received once daily doses of either vildagliptin 100 mg or simvastatin 80 mg or the combination for 7 days with an inter-period washout of 7 days. Plasma levels of vildagliptin, simvastatin, and its active metabolite, simvastatin β-hydroxy acid (major active metabolite of simvastatin) were determined using validated LC/MS/MS methods. Pharmacokinetic and statistical analyses were performed using WinNonlin and SAS, respectively.Results: The 90% confidence intervals of Cmax and AUCτ of vildagliptin, simvastatin, and simvastatin β-hydroxy acid were between 80 and 125% (bioequivalence range) when vildagliptin and simvastatin were administered alone and in combination. These data indicate that the rate and extent of absorption of vildagliptin and simvastatin were not affected when co-administered, nor was the metabolic conversion of simvastatin to its active metabolite. All treatments were safe and well tolerated in this study.Conclusions: The pharmacokinetics of vildagliptin, simvastatin, and its active metabolite were not altered when vildagliptin and simvastatin were co-administered.

The effects of lacidipine on the steady/state plasma concentrations of simvastatin in healthy subjects

The effects of lacidipine on the steady/state plasma concentrations of simvastatin in healthy subjects

The effects of lacidipine on the steady/state plasma concentrations of simvastatin in healthy subjects

Aims Lacidipine, a long acting 2, 4‐dihydropyridine calcium channel antagonist is frequently administered with cholesterol lowering agents, particularly in elderly populations. The effects of lacidipine on the pharmacokinetics of simvastatin were investigated, since they share the CYP3A4 pathway for metabolism. Methods The study was an open, randomised, two‐way crossover design, with at least 7 days washout. Eighteen healthy subjects received simvastatin, 40 mg once daily, alone and together with lacidipine, 4 mg once daily, for 8 days. The pharmacokinetics of simvastatin were studied on the eighth day. Analysis was made of total simvastatin acid concentrations (naive simvastatin acid plus that derived from alkaline hydrolysis of the lactone). Results Lacidipine increased the maximum concentration of simvastatin (Cmax) by approximately 70% (P=0.016) and the area under the plasma concentration‐time curve AUC(0,24 h) by approximately 35% (P=0.001). The mean Cmax and AUC(0,24 h) of simvastatin (95% confidence interval) when given alone were 8.76 (6.72–11.41) ng ml−1 and 60.36 (47.15–77.28) ng ml−1 h. During treatment with lacidipine they were, respectively, 14.89 (10.77–20.58) ng ml−1 and 80.96 (64.62–101.44) ng ml−1 h. No significant differences were observed in either time to peak concentration (tmax was 1.0 h for simvastatin alone and 1.5 h for the combination) or in the half‐life (t1/2,z was 8.5 h in both cases). The combination was safe and well tolerated. Conclusions The observed increased exposure to simvastatin 40 mg following coadministration of lacidipine is unlikely to be of clinical relevance.