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Comparing hyperlipidemia control with daily versus twice-weekly simvastatin.

BACKGROUND: Costs associated with the use of hydroxymethylglutaryl coenzyme A reductase inhibitors are increasing. Finding ways to manage hyperlipidemia at lower costs is critical to all healthcare systems. OBJECTIVE: To assess effectiveness, safety, cost, and patients' satisfaction when converting hyperlipemic patients taking simvastatin daily to simvastatin twice weekly. METHODS: This nonrandomized, open-label, proof-of-concept study converted patients treated with simvastatin 10 or 20 mg daily to 40 or 80 mg twice weekly, respectively, for 12 weeks. The lipid profiles at enrollment, week 6, and week 12 were compared using repeated-measures ANOVA. The percentage of patients attaining the appropriate low-density lipoprotein cholesterol (LDL-C) goal was determined. RESULTS: Thirty-one patients completed the study. The proportion of patients at the LDL-C goal was not statistically different between enrollment and week 12 (87% vs 68%; p = 0.068). The mean LDL-C value +/- SD at weeks 6 and 12 increased compared with enrollment (112 +/-20, 111 +/-17, and 97 +/- 17 mg/dL, respectively; p < 0.001). Three (10%) patients reported nonadherence to the twice-weekly regimen. Seventeen (55%) patients reported that both regimens were equally convenient or preferred the twice-weekly regimen. Estimated cost-savings at our institution associated with this regimen would be $32 000 per 1000 patients per year. CONCLUSIONS: The twice-weekly regimen safely maintained most of the patients at their LDL-C goal level, and over half the patients found this regimen to be the same or easier to follow than a daily regimen. Large outcome studies evaluating this approach are needed.

Adult↗

The use of simvastatin for the prevention of gallstones in the lithogenic prairie dog model.

BACKGROUND: Surgery for morbid obesity is rapidly increasing. Patients undergoing bariatric surgery are prone to gallstone development during the rapid weight loss. These patients are often given medications such as ursodeoxycholic acid to prevent gallstone formation; however, these medications are often poorly tolerated by patients, who subsequently discontinue them. We performed a study in a lithogenic animal model to assess the effectiveness of a potential alternate medication for gallstone prevention. METHODS: 20 male prairie dogs were randomly separated into 2 groups and fed a lithogenic diet for 28 days. The study group animals were given 2.5 mg of the HMG-CoA reductase inhibitor simvastatin. Total cholesterol and triglycerides were measured and an open cholecystectomy was performed on each animal at the conclusion of the study period. The gallbladder was visually inspected for gallstones and microscopic biliary cholesterol crystal formation. RESULTS: There was a decrease of 36% in the total cholesterol of the study animals compared to controls. The animals treated with simvastatin showed gallstone formation in 5/10 (50%) of animals, compared with 6/10 (60%) of control animals. The study animals demonstrated microscopic cholesterol crystal formation in 80%, identical to the number found in the control animals. CONCLUSION: Despite a reduction in cholesterol, simvastatin prevented neither gallstone formation nor biliary cholesterol crystals in this animal model. Given the rapid increase in the number of bariatric surgical procedures coupled with the poor tolerance of ursodeoxycholic acid, viable alternatives should continue to be sought for these patients.

Animals↗

Simvastatin could prevent increase of the serum MMP-9/TIMP-1 ratio in acute ischaemic stroke.

MMP-9 plays an important role in the pathogenesis of AIS and predicts haemorrhagic transformation of the ischaemic focus. The aim of our study was to analyse both serum MMP-9 and its most specific endogenous inhibitor (TIMP-1) levels in AIS and to check whether HMG-CoA reductase inhibitor (simvastatin) affects the MMP-9/TIMP-1 ratio value. Fifty patients with AIS were randomly divided into two groups: Group I (N = 25) treated with 40 mg/day with simvastatin within 24 hours after the onset of stroke and Group II (N = 25) non-treated with statin. To evaluate MMP-9 and TIMP-1 serum levels, the ELISA method was used. The serum MMP-9 level was significantly elevated on the 7th day of stroke in both groups (from 668 to 862 ng/ml and 670 to 855 ng/ml, respectively, in Group I and II). The serum TIMP-1 level was also elevated on the 7th day of stroke in both groups but the results were not significant. The MMP-9/TIMP-1 ratio was elevated on the 7th day of stroke in both groups, but the result was significant only in the Group II (P < 0.01). These findings indicate that simvastatin given during 24 hours after the onset of stroke could have an influence on the MMP-9/TIMP-1 ratio during AIS.

Aged↗

Dual effect of lovastatin and simvastatin on LDL-macrophage interaction.

Lovastatin and simvastatin which are very potent cellular cholesterol biosynthesis inhibitors, significantly affect the plasma lipoprotein concentration. After incubation of plasma with 14C-labelled compounds, radioactivity was found in all lipoprotein fractions but mainly (40%) in high density lipoprotein (HDL), and in the lipoprotein-deficient plasma fraction (20-30%). Drug-treated lipoproteins showed reduced electrophoretic mobility on cellulose acetate in comparison with control lipoproteins. The lovastatin-treated low density lipoprotein (LDL) displayed 28% increased fluidity in comparison with control LDL. The immunoreactivity of drug-treated LDL with monoclonal antibody directed towards the LDL receptor binding domains (B1B6) was significantly less than that of control LDL, suggesting reduced binding to the LDL receptor. When drug-treated LDL was incubated with J-774 A.1 macrophage-like cell line, its binding (at 4 degrees C) was 28% less than that of control LDL, whereas a substantial increase in the cellular cholesterol esterification rate (by 83% with lovastatin and by 67% with simvastatin) was noted. Similarly, the degradation of lovastatin and simvastatin-treated LDL by macrophages was 87-89% greater than that of control LDL. The "apparent Vmax" for the macrophage degradation of lovastatin-treated LDL was 70% greater than that for control LDL. Thus, both drugs may have a dual effect on the macrophage uptake of LDL; they may increase the number of LDL receptors on the cell surface, but they may also reduce the affinity of LDL for its receptor, the former being the major effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[Effects of atorvastatin, fluvastatin, pravastatin, and simvastatin on endothelial function, lipid peroxidation, and aortic atherosclerosis in hypercholesterolemic rabbits].

OBJECTIVE: To compare the effects of atorvastatin, fluvastatin, pravastatin, and simvastatin on endothelial function, aortic atherosclerosis, and the content of malondialdehyde (MDA) in native and oxidized LDL and in the arterial wall of hypercholesterolemic rabbits after adjusting the dosages of those statins to reduce total serum cholesterol levels to similar values. METHODS: Male rabbits were divided into the following 6 groups of 10 animals (n=10): 1) GH (control)--hypercholesterolemic animals; 2) GA--atorvastatin; 3) GF--fluvastatin; 4) GP--pravastatin; 5) GS--simvastatin; and 6) GN--normal. The animals were fed a standard food preparation enriched with 0.5% cholesterol and 2% coconut oil for 45 days. Fifteen days after beginning the experiment, atorvastatin, fluvastatin, pravastatin and simvastatin were administered for 15 days through gavage, and the dosages were adjusted to obtain similar cholesterol values in each group. At the end of the experiment, a blood sample was withdrawn for determining total cholesterol and separating the lipoproteins, and a segment of the thoracic aorta was removed to be used for studying endothelial function and lipid peroxidation, and for measuring aortic atherosclerosis in histological sections. RESULTS: The statins significantly reduced total serum cholesterol levels, LDL-cholesterol levels, and aortic atherosclerosis. The MDA content was also significantly reduced in native and oxidized LDL, as well as in the arterial wall. Endothelium-dependent relaxation was significantly greater in the treated group compared with that in the hypercholesterolemic group. CONCLUSION: The statins, at dosages adjusted, had a significant and similar effect in reducing lipid peroxidation in native and oxidized LDL-C and in arterial walls, in decreasing aortic atherosclerosis, and in reverting endothelial dysfunction.

Animals↗

The outcome of very low dosages of simvastatin in patients with hypercholesterolemia.

A retrospective study evaluated the success of dosages of simvastatin lower than the 10-20 mg/day recommended by the manufacturer in patients with hypercholesterolemia. Records of 95 patients enrolled in a pharmacist-managed lipid clinic receiving stable dosages of simvastatin were reviewed. Data collected were demographics, number of simvastatin refills, dosage distribution, baseline and posttreatment lipid profiles, and proportion of patients with low-density lipoprotein (LDL) levels below target as recommended by the National Cholesterol and Education Program. Dosages for 62% of patients were less than 20 mg/day. Percentages of patients at goal LDL were 98%, 89%, and 83% for patients taking 2.5, 5, and 10 mg/day, respectively. Patients taking 40 mg/day were least likely to be below the goal. There was an even distribution of patients taking each dosage. No statistical difference in compliance was noted among dosages based on prescription refills. Most patients taking less than the recommended initial dosage of the agent had satisfactory lipid control.

Aged↗

The cost of reaching National Cholesterol Education Program (NCEP) goals in hypercholesterolaemic patients. A comparison of atorvastatin, simvastatin, lovastatin and fluvastatin.

OBJECTIVE: Recognising the importance of treating hyperlipidaemia, the National Cholesterol Education Program (NCEP) has established widely accepted treatment goals for low density lipoprotein cholesterol (LDL-C). Medications used most commonly to achieve these LDL-C goals are HMG-CoA reductase inhibitors. The relative resource utilisation and cost associated with the use of reductase inhibitors of different LDL-C lowering efficacy are unknown, but are major health and economic concerns. The objective of this study was to determine the mean total cost of care to reach NCEP goals with various reductase inhibitors. DESIGN: In a randomised, 54-week, 30-centre controlled trial we compared resources used and costs associated with treating patients to achieve NCEP goals using 4 reductase inhibitors: atorvastatin, simvastatin, lovastatin and fluvastatin. PATIENTS AND PARTICIPANTS: The trial studied 662 patients; 318 had known atherosclerotic disease. INTERVENTIONS: Reductase inhibitor therapy was initiated at recommended starting doses and increased according to NCEP guidelines and package insert information. For patients who did not reach the goal at the highest recommended dose of each reductase inhibitor, the resin colestipol was added. MAIN OUTCOME MEASURES AND RESULTS: Patients treated with atorvastatin, compared-with other reductase inhibitors, were more likely to reach NCEP goals during treatment (p < 0.05), required fewer office visits (p < 0.001) and less adjuvant colestipol therapy (p = 0.001). Consequently, the mean total cost of care (1996 values) to reach NCEP goals was lower with atorvastatin [$US1064; 95% confidence interval (CI): $US953 to $US1176] compared with simvastatin ($US1471, 95% CI: $US1304 to $US1648), lovastatin ($US1972; 95% CI: $US1758 to $US2186) and fluvastatin ($US1542; 95% CI: $US1384 to $US1710). Results were similar for patients with or without known atherosclerotic disease. CONCLUSIONS: In patients requiring drug therapy for hypercholesterolaemia, NCEP LDL-C goals are achieved significantly more often using fewer resources with atorvastatin compared with simvastatin, lovastatin or fluvastatin.

Aged↗

Simvastatin inhibits tissue factor and plasminogen activator inhibitor-1 expression of glomerular mesangial cells in hypercholesterolemic rabbits.

Tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) activity and/or expression are upregulated in hypercholesterolemia. Despite extensive research on anti-thrombotic effect of statins, little is known about their effects on TF and PAI-1 expression in glomerular mesangial cells under hypercholesterolemic condition. Male rabbits were fed on either normal or high-cholesterol diet for 8 weeks. Then cholesterol-fed rabbits were randomly assigned to simvastatin or starch. At the end of 12 weeks, glomerular mesangial cells were collected. The concentrations of TF and PAI-1 mRNA were detected by RT-PCR. The plasma activities of TF and PAI-1 were determined with enzyme linked immunosorbent assay (ELISA) and chromogenic substrate method, respectively. The atherogenic diet caused a consistent increase in serum concentrations of total cholesterol (TC) and serum triglyceride (TG) (p < 0.05), increased TF and PAI-1 mRNA expression in glomerular mesangial cells and plasma activities as compared to the normal diet (p < 0.01). Four-week simvastatin treatment resulted in significant decrease of mesangial TF and PAI-1 mRNA (p < 0.01), and also of the plasma activities of TF (p < 0.05) and PAI-1 (p < 0.01). These results suggest that simvastatin might protect kidney from the formation of microthrombus under hypercholesterolemic condition and might be a possible pathogenesis of obesity-related glomerulopathy.

Acyl Coenzyme A↗

Effects of simvastatin on bone regeneration in the mandibles of ovariectomized rats and on blood cholesterol levels.

The purpose of this study was to evaluate the effects of simvastatin on guided bone regeneration in the mandibles of ovariectomized rats, and to observe their blood cholesterol levels. Seventy female rats were divided into two groups: control and treated, both groups containing normal and ovariectomized rats. A month after ovariectomy a bone defect was created in the mandible, and was covered by a polytetrafluoroethylene membrane. The treated groups received simvastatin orally for 15 or 30 days. The rats were sacrificed 15, 30 or 60 days after surgery, at which time a blood sample was extracted for blood cholesterol level analysis and the mandible was extracted for densitometric, histological and morphometric analysis. All specimens underwent analysis of variance. The ovariectomized animals had higher cholesterol levels than the treated normal animals, and no significant difference was found between the different treatment periods and the sacrifice times. The densitometric, histological and morphometric analysis showed that the treated ovariectomized animals developed more new bone than the control ovariectomized rats, but no significant difference was observed between the treatment periods. It can be concluded that the deficiency of estrogen increased the level of blood cholesterol and that the simvastatin aided new bone formation in the ovariectomized animals.

Absorptiometry, Photon↗

Effects of simvastatin, a lipoprotein-lowering drug, on the hepatic enzymes involved in drug metabolism in the Wistar rat.

1. Simvastatin, a competitive inhibitor of 3-hydroxy-3-methyl glutaryl CoA reductase, lowers the plasma cholesterol level and has been approved for treatment of hyperlipoproteinaemia. 2. Simvastatin has been studied for its effects on hepatic microsomal drug metabolism in rat. No induction of 7-ethoxyresorufin-O-deethylase (EROD), ethoxycoumarin-O-deethylase (ECOD) and of UDP-glucuronosyltransferases were found, in vitro, after administration of 0.5, 1.5 and 10 mg/kg per day for 22 days. 3. Epoxide hydrolases (microsomal and cytosolic) were also unchanged after treatment with simvastatin. 4. No increase of the palmitoyl CoA oxidase activity or of mitochondrial glycerol phosphate dehydrogenase activity occurred. 5. Fatty acid distribution in rat liver microsomal phosphatidylcholines showed a significant decrease of C16:1 and a significant increase of C20:4 acids.

Animals↗

Effects of fenofibrate and simvastatin on plasma sICAM-1 and MCP-1 concentrations in patients with hyperlipoproteinemia.

OBJECTIVE: The most important mechanism through which high plasma lipid levels trigger the formation of atherosclerotic lesions involves a change in the expression of adhesion molecules on endothelial and smooth muscle cells. The aim of this study was to evaluate an extralipid effect of fenofibrate and simvastatin by examination of MCP-1 and ICAM-1 plasma concentration after 1-month hypolipemic therapy as well as MCP-1 and ICAM-1 plasma concentration after 1-month therapy with low-fat diet alone. METHODS: Twenty patients with HLPIIb or HLPIIa, who did not respond to a low-fat diet, were treated with micronized fenofibrate or simvastatin, respectively, for 1 month. The control group included 18 normo-lipidemic, healthy age-matched participants; 10 patients with HLPIIa were effectively treated with a low-fat diet for 1 month. This group was compared to a control group of 10 healthy subjects. The plasma adhesion molecule levels were measured by an ELISA method before and after the treatment. To accurately evaluate the adhesion molecule levels, we excluded hyperlipidemic patients and control subjects with any inflammatory disease. RESULTS: sICAM-1 levels were significantly higher in HLPIIa and HLPIIb patients (331 +/- 19 ng/ml and 423 +/- 23 ng/ml, respectively) compared with the control group (236 +/- 12 mg/ml). MCP-1 levels were also significantly higher in HLPIIa and HLPIIb patients (170 +/- 9 pg/ml and 183 +/- 15 pg/ml, respectively) compared with the control group (100 +/- 4 pg/ml). Fenofibrate (200 mg daily) significantly decreased sICAM-1 (by 17%) and MCP-1 levels (by 12.5%). Simvastatin (20 mg daily) caused a significant decrease (by 10.5%) in sICAM-1 levels only. Restriction in dietary lipids resulted in a significant decrease in the levels of cholesterol (8%), LDL cholesterol (14.9%) and ApoB (12.7%), which was accompanied by a significant decrease in the levels of sICAM-1 (8.7%) and MCP-1 (16.1%). CONCLUSION: The results of this study suggest that high lipid levels are accompanied by increased levels of sICAM-1 and MCP-1 and that hypolipidemic therapy only slightly decreases the levels of these molecules compared with plasma lipids. The hypolipidemic diet-related decrease in the levels of lipids, ICAM-1 and MCP-1 suggests that it is a drug-induced decrease in lipid levels but not a direct action of the drugs on endothelial cells, smooth muscle cells or macrophages that leads to a decrease in the levels of adhesion molecules.

Chemokine CCL2↗

Diet only and diet plus simvastatin in the treatment of heterozygous familial hypercholesterolemia in childhood.

This study was a 1-year clinical study on 16 (7 males and 9 females) pediatric patients with heterozygous familial hypercholesterolemia treated with hypocholesterolemic diet only, or with diet plus drug (simvastatin 10 mg/day). According to the study protocol, the children were submitted to a 3-month washout (free diet). Then they were given a diet (American Heart Association, step 2) for 6 months. After 6 months they were divided into two groups matched for sex, age and body mass index (BMI). Diet only was given to group A (n = 8); simvastatin (10 mg/daily) was given to group B, for 1 year. All patients were examined at baseline, and monitored for safety during the study by pediatricians. All patients were submitted to noninvasive cardiovascular examinations (exercise electrocardiogram, echocardiography). After 12 months of treatment with simvastatin, total cholesterol (TC) and low density lipoprotein cholesterol (LDLC) showed a statistically significant reduction (group B). The decrease of TC and LDLC in patients on diet only was 4% and 3% (all) and 17% and 4% (group A) after 6 and 12 months, respectively.

Anticholesteremic Agents↗

Differential regulation of apolipoprotein B secretion from HepG2 cells by two HMG-CoA reductase inhibitors, atorvastatin and simvastatin.

The concept that hepatic cholesterol synthesis regulates hepatocyte assembly and secretion of apoB-containing lipoproteins remains controversial. The present study was carried out in HepG2 cells to examine the regulation of apoB secretion by the HMG-CoA reductase inhibitor atorvastatin. ApoB accumulation in the media was decreased by 24% and 36% at 10 microm (P < 0.02) and 20 microm (P < 0.01) of atorvastatin, respectively. Atorvastatin inhibited HepG2 cell cholesterol synthesis by up to 96% (P < 0.001) and cellular cholesteryl ester (CE) mass by 54% (P < 0.001). Another HMG-CoA reductase inhibitor, simvastatin, decreased cellular cholesterol synthesis and CE mass by up to 96% (P < 0.001) and 52% (P < 0.001), respectively. However, in contrast to atorvastatin, simvastatin had no effect on apoB secretion. To characterize the reduction in apoB secretion by atorvastatin (10 microm), pulse-chase experiments were performed and the kinetic data were analyzed by multicompartmental modeling using SAAM II. Atorvastatin had no affect on the synthesis of apoB, however, apoB secretion into the media was decreased by 44% (P = 0.048). Intracellular apoB degradation increased proportionately (P = 0.048). Simvastatin (10 microm) treatment did not significantly alter either the secretion or intracellular degradation of apoB, relative to control. The kinetics of apoB degradation were best described by a rapidly and a slowly turning over degradation compartment. The effect of atorvastatin on apoB degradation was largely confined to the rapid compartment. Neither inhibitor affected apoB mRNA concentrations, however, both significantly increased LDL receptor and HMG-CoA reductase mRNA levels. Atorvastatin treatment also decreased the mRNA for the microsomal triglyceride transfer protein (MTP) by 22% (P < 0.02). These results show that atorvastatin decreases apoB secretion, by a mechanism that results in an enhanced intracellular degradation in apoB.

Apolipoproteins B↗

HDL-cholesterol and the treatment of coronary heart disease: contrasting effects of atorvastatin and simvastatin.

Although the levels of low-density lipoprotein (LDL) cholesterol remain the main therapeutic goal when treating dyslipidaemias, there is a need to consider high-density lipoprotein (HDL) concentrations. This conclusion is based on the findings of epidemiological surveys and appropriately designed trials using statins or fibrates. The importance of HDL, as a 'protective' lipoprotein fraction, has been recognised by major treatment guidelines. This review considers the differences in HDL-raising capacity of two of the most commonly prescribed statins--atorvastatin and simvastatin. When compared with simvastatin, atorvastatin is associated with progressively decreasing rises in the levels of HDL as the dose increases (negative dose response), an effect not reported with other statins. In contrast, simvastatin shows a positive dose response (increasing concentrations of HDL with increasing dose). This effect is paralleled by changes in apolipoprotein A-I levels. Apolipoprotein A-I is the main apolipoprotein associated with HDL. This dissimilarity in HDL response is an example of several differences that have been reported when comparing various statins. If 'all statins are not created equal', we should focus prescribing on those statins that have end point evidence originating from appropriately designed trials.

Anticholesteremic Agents↗

Similar effects of atorvastatin, simvastatin and pravastatin on thrombogenic and inflammatory parameters in patients with hypercholesterolemia.

BACKGROUND: Previous studies have suggested that statins exert beneficial effects beyond their favorable lipid lowering effect. Particularly, the modification of thrombus formation and degradation, alteration in inflammatory response, plaque stabilization and improved endothelial function are thought to be responsible for additional reduction of morbidity and mortality due to cardiovascular events. To date, however, it is still unclear whether these effects are elicited by all statins. METHODS AND RESULTS: We set out to compare in a controlled, randomized, double-blind study design the effects of almost equieffective cholesterol lowering doses of three chemically and pharmacokinetically different statins (atorvastatin, simvastatin, pravastatin) on hemostatic and inflammatory markers in 99 hypercholesterolemic patients. At entry and 3 months after onset of statin therapy plasma cholesterol and von Willebrand factor antigen (vWf-Ag), fibrinogen, d-dimer, prothrombin fragment 1+2 (F1.2) and C-reactive protein (CRP) were measured. The effect on plasma values of F1.2, vWf-Ag, d-dimer and CRP was not significantly different between the three treatment groups. The effect of simvastatin on fibrinogen (p = 0.005) was more pronounced than the effects of atorvastatin (p = 0.48 n.s.) and pravastatin (p = 0.15 n.s.). Plasma levels of F1.2 and vWf-Ag (when data of all statins were pooled) were significantly reduced by 7% and 10% versus baseline, respectively. No significant reduction was observed for d-dimer (p = 0.26) and CRP (p = 0.5). Total plasma cholesterol levels decreased significantly (p < 0.0001 in all groups) between 22% and 29% compared to baseline. CONCLUSION: The present study shows similar short-term (3 months) effects of atorvastatin, simvastatin and pravastatin on selected hemostatic and inflammatory parameters in plasma in patients with hypercholesterolemia. Thus, chemical and pharmacological differences between statins appear to exert no major influence on these parameters.

Adult↗

Treatment with simvastatin and low-dose aspirin depresses thrombin generation in patients with coronary heart disease and borderline-high cholesterol levels.

Aspirin and statins are beneficial in coronary heart disease across a broad range of cholesterol levels. We assessed the effects of low-dose aspirin (75 mg daily) on thrombin generation in patients with coronary heart disease and average blood cholesterol levels. We also investigated whether in patients with borderline-high cholesterol level who have been already taking aspirin, additional treatment with simvastatin would affect thrombin generation. Seven-day treatment with low-dose aspirin decreased thrombin generation ex vivo only in patients with total cholesterol < or = 5.2 mmol/L. In patients with higher cholesterol levels aspirin had no effect. In these patients, already taking low-dose aspirin, additional three-month simvastatin treatment resulted in a reduction of thrombin generation. This demonstrates that low-dose aspirin depresses thrombin generation only in subjects with desirable blood cholesterol levels, while in others, with borderline-high cholesterol, thrombin formation is being reduced following the addition of simvastatin.

Adult↗

beta-Oxidation of simvastatin in mouse liver preparations.

All current 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors [simvastatin (SV), lovastatin (LV), atorvastatin, pravastatin, fluvastatin, and cerivastatin] are believed to undergo an atypical beta-oxidation of the dihydroxy heptanoic or heptanoic acid side chain. Metabolites, which are shortened by two- and/or four-carbon units consistent with beta-oxidation products, have been reported exclusively in rodents following LV and SV administration and across species (rodents, dogs, and humans) following the other statins. In this study, in vitro formation of a beta-oxidation product of simvastatin hydroxy acid (SVA) and its intermediates in mouse livers is described. Incubation of SVA with mouse liver preparations fortified with CoASH and ATP led to formation of SV and two major products (P1 and P2). Based on mass spectrometry (MS), tandem mass spectrometry, and/or NMR spectral characteristics, P1 was an alpha,beta-unsaturated metabolite, formed by dehydration of the D,D-dihydroxy heptanoic acid side chain, whereas P2 was probably the L,D-dihydroxy acid isomer of SVA, formed by stereospecific hydration of P1. When NAD(+) was also included in the incubation mixture, there were two additional metabolites with the MS and/or NMR characteristics consistent with a two-carbon shortened product (P3) and its dehydrated derivative (P4). In a complete incubation system with all cofactors (ATP, CoASH, NAD(+), and NADPH) present, there was an additional product with MS spectra and liquid chromatography retention time identical to the beta-oxidized, unsubstituted pentanoic acid metabolite (P5) detected in rats and mice following simvastatin administration. The involvement of CoASH and NAD(+) and the presence of the four metabolic intermediates suggest that SVA (and presumably the other statins) is a substrate for the beta-oxidation enzyme complex in mice. Additionally, the present finding of CoASH-dependent formation of SV substantiates a mechanism proposed previously for the in vivo lactonization of statin hydroxy acids.

Animals↗

Comparison of therapy with simvastatin 80 mg and 120 mg in patients with familial hypercholesterolaemia.

High-dose preparations of simvastatin and atorvastatin have recently become available to treat resistant hypercholesterolaemia aggressively, but few studies have compared these two agents. This study compared the efficacy of simvastatin 80 mg and 120 mg in 22 patients with severe familial hypercholesterolaemia over a three-month period using an open label format. Simvastatin 120 mg was reasonably well tolerated and delivered a further 8% reduction in LDL over 80 mg, giving a total reduction of 55 +/- 13%, while further decreasing triglycerides (18%) and continuing to raise HDL (13%) further than the 80 mg dose. However, transient adverse changes were noted in both lipoprotein (a) and fibrinogen and 20% of patients were unable to tolerate the higher dose. One late case of rhabdomyolysis was observed, suggesting patients on the 120 mg dose require continued regular review.

Adult↗