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Simvastatin-diltiazem drug interaction resulting in rhabdomyolysis and hepatitis.

Simvastatin, a hydroxymethyl glutarate coenzyme A (HMG-CoA) reductase inhibitor, is a commonly used cholesterol lowering agent. The long-term safety profile of simvastatin, established over ten-years of clinical use, is excellent. Both rhabdomyolysis and hepatitis, however, are recognized toxic effects of this medication, and generally occur when the patients are taking more than 40 mg of simvastatin a day. Potent inhibitors of the cytochrome P450 3A4 (CYP3A4) enzyme increase the incidence of simvastatin toxicity. Calcium channel blockers are weak inhibitors of the CYP3A4 enzyme. Diltiazem is known to increase the serum concentration of simvastatin. Many patients who take both simvastatin and diltiazem require lower doses of simvastatin to achieve the recommended reduction in cholesterol. Since diltiazem is known to increase plasma levels of lovastatin, a similar phenomenon may occur with simvastatin. Our patient had been stable for three years on simvastatin therapy. His rhabdomyolysis and hepatitis coincided with the addition of diltiazem. This is the first report of the combined toxicities of rhabdomyolysis and hepatitis being induced by the addition of diltiazem to simvastatin therapy. This patient serves as a reminder to the clinician of the potential interaction of these two commonly used drugs.

Calcium Channel Blockers↗

In vivo enhanced antitumor activity of carmustine [N,N'-bis(2-chloroethyl)-N-nitrosourea] by simvastatin.

The effects of a combination of simvastatin, a cholesterol-lowering agent, and carmustine (BCNU; N,N'-bis(2-chloroethyl)-N-nitrosourea) on experimental C6 glioma were studied in vitro and in vivo. In vitro simvastatin and BCNU alone inhibited cell proliferation in a dose-dependent fashion. A subliminal concentration of simvastatin (0.1 microM) markedly and synergistically increased the BCNU toxicity to C6 glioma cells. The cytofluorimetric analysis of DNA from simvastatin-treated C6 glioma cells showed, besides the already described arrest in G1, an arrest/retardation in G2-M. Mitotic index from C6 cells incubated with simvastatin (10 microM) decreased by about 90%, indicating a specific C6 arrest/retardation in G2. The drug effects could be completely reversed by simvastatin withdrawal or mevalonate addition to the cultured cells. The combination of simvastatin and BCNU resulted predominantly from the profound retardation of cells in the G2-M compartment of the cell cycle. In vivo simvastatin (administered daily mixed with food) and BCNU (single i.p. injection), when given separately, caused a dose-dependent inhibition of labeling index in C6 glioma homografts (ID50, 61 mg/kg/day and 8.7 mg/kg, respectively). The combination of the lowest doses tested (simvastatin, 25 mg/kg/day and BCNU 0.3 mg/kg) resulted in a significant growth delay (compared to either drug alone) in C6 glioma (P < 0.05). There was no significant increase in toxicity as assessed by myelosuppression (WBC counts and bone marrow labeling index) and body weight. The results provide in vivo support for the combined use of simvastatin, a cholesterol-lowering agent, and BCNU in brain tumor treatment.

Animals↗

Simvastatin compared to fluvastatin in the reduction of serum lipids and apolipoproteins in patients with ischaemic heart disease and moderate hypercholesterolaemia.

OBJECTIVE: Inhibitors of HMG-CoA reductase are widely used for the treatment of hypercholesterolaemia and have recently been shown in the Scandinavian Simvastatin Survival Study (4S), to reduce coronary mortality as well as total mortality in CH D patients. Although a couple of studies have already established the efficacy ratio between simvastatin and fluvastatin, one of the newest members of this class, we considered it to be important to verify the comparative efficacy in patients with coronary artery disease in the same type of patients that were included in 4S particularly since the previous studies include rather few patients with CHD, 17-28% only. METHODS AND RESULTS: Three Scandinavian lipid clinics participated in this randomized double-blind study and enrolled a total of 113 hypercholesterolaemic patients with a profile similar to the 4S patients, i.e. either a history of typical angina pectoris lasting at least three months or a myocardial infarction at least six months before the study and with moderate hypercholesterolaemia, total serum cholesterol between 5.5 and 8.0 mmol/l. After a diet run-in period lasting at least 8 weeks, followed by a two week placebo period, patients received treatment with active drug for a 16 week period, with measurement of lipids using the same technique and laboratory as was used in 4S. Patients were randomly assigned to simvastatin 20 mg or fluvastatin 20 mg. If after 6 weeks of double-blind treatment, the 4S total cholesterol target of < or = 5.2 mmol/l total serum cholesterol had not been reached, the dose was doubled at the next visit, i.e. at week 10 based upon blinded titration information from the central lipid laboratory like in the 4S study. A final assessment of serum lipids and lipoproteins was made at week 16. The mean percent reductions in LDL-cholesterol from baseline were 37% and 40% in the simvastatin group compared to 19% and 26% in the fluvastatin group, at weeks 10 and 16, respectively (p < 0.001). In the simvastatin group 18 percent of the patients needed an increase in the dose to 40 mg compared to 63 percent in the fluvastatin group (p < 0.001). At the 20 mg dosage, simvastatin produced a lowering of LDL-cholesterol approximately twice that of fluvastatin 20 mg and resulted in 82% of patients achieving the cholesterol target levels as defined in the 4S study, compared to 19% for fluvastatin. All other recorded lipid variables showed differences which favoured simvastatin over fluvastatin at comparable doses including serum triglyceride reductions where serum triglycerides at week 6 were borderline significantly different between the two groups. Patient tolerability of the two drugs was similar. CONCLUSION: At the recommended doses in patient with angina or a prior MI and mild to moderate hypercholesterolaemia simvastatin is considerably more effective than fluvastatin in lowering serum total cholesterol, LDL-cholesterol as well as other serum lipid risk factors. At an average titrated dose of 32 mg less than 50% of the fluvastatin patients reached the 4S cholesterol target of < 5.2 mmol/l compared to 89% of the simvastatin patients at an average dose of 23 mg daily and only 13% of the fluvastatin patients achieved an LDL-cholesterol reduction of at least 40% compared to 63% of the simvastatin patients.

Analysis of Variance↗

The effect of simvastatin, ezetimibe and their combination on the lipid profile, arterial stiffness and inflammatory markers.

OBJECTIVE: Arterial stiffness and highly sensitive C-reactive protein (hsCRP) serum level predict the risk for cardiovascular events. The most commonly used drugs for lowering cholesterol levels, the statins, also have anti-inflammatory effects and can decrease arterial stiffness. Ezetimibe is the first drug of a new class of cholesterol absorption inhibitors in common use and, to date, its effect on arterial stiffness has not yet been studied. The aim of this study was to compare the effect of simvastatin and ezetimibe, both singly and in combination, on arterial stiffness and hsCRP serum concentration in hypercholesterolemic patients. METHODS: Forty hypercholesterolemic patients were studied. Group1 comprised previously untreated patients, who received simvastatin at doses of 40 mg/day during the study; group 2 comprised patients previously treated with simvastatin at 40 mg/day, who received simvastatin at 80 mg/day during the study; group 3 consisted of patients previously untreated, who received ezetimibe at doses of 10 mg/day during the study; group 4 comprised patients previously treated with simvastatin at 40 mg/day, who received simvastatin at 40 mg/day and ezetimibe at 10 mg/day during the study. Arterial stiffness expressed as the Augmentation Index (AIx) (assessed by pulse wave analysis), the lipid profile and the hsCRP level were measured at baseline and after 3 months of treatment. RESULTS: The reduction in low-density lipoprotein (LDL) after treatment was significantly greater in groups 1 and 4 (39.9 and 35.7%) than in groups 2 and 3 (17.7 and 16.9%; p = 0.005). The AIx decreased significantly only in group 1 patients, from 30.2 +/- 8.3% before treatment to 21.6 +/- 6.5% after treatment (p < 0.001). Changes in hsCRP paralleled the changes in AIx, with a significant decrease in patients in group 1 only, from 2.8 +/- 2.5 mg/L before treatment to 1.6 +/- 1.5 mg/L after treatment (p = 0.016). CONCLUSION: Ezetimibe as a monotherapy had no effect on arterial stiffness or hsCRP, while the administration of simvastatin at 40 mg per day improved arterial stiffness and CRP. However, increasing the dose of simvastatin or administering ezetimibe in combination with simvastatin had no beneficial effects on arterial stiffness.

Aged↗

Comparative effects of simvastatin and cholestyramine in treatment of patients with hypercholesterolaemia.

The efficacy and safety of 20 mg simvastatin (a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor) and of 16 g cholestyramine daily in the treatment of 34 hypercholesterolaemic patients have been compared after dietary treatment and stratified randomization. The effect of combined treatment with the two drugs was studied in 5 patients with severe hypercholesterolaemia. After 6 weeks of treatment the simvastatin group showed a significantly greater (p less than 0.05) decrease in the mean total plasma cholesterol concentration from 7.88 to 5.48 mmol/l than in the cholestyramine group in whom there was a fall from 7.82 to 6.73 mmol/l. Simvastatin decreased the mean plasma LDL cholesterol concentration from 6.07 to 3.76 mml/l and cholestyramine decreased it from 6.16 to 4.46 mmol/l. Simvastatin also reduced the mean plasma total triglycerides by 24%, VLDL triglycerides by 20% and VLDL cholesterol by 36%, while cholestyramine led to increases in these parameters by 64%, 85% and 63%, respectively. Mean plasma HDL cholesterol concentration and the subfractions HDL2 and HDL3 cholesterol were significantly increased by simvastatin. Simvastatin and cholestyramine reduced the mean plasma apolipoprotein B concentration by 28% and 13%, respectively. The mean plasma apolipoprotein A-I concentration was significantly higher only on simvastatin treatment. Simvastatin did not cause any subjective or objective side effects, while cholestyramine caused gastrointestinal problems in 31% of patients. Small increases in serum alanine aminotransferase (S-ALT) activity were seen with both drugs. Cholestyramine significantly raised the serum alkaline phosphatase (S-ALP) although to a level still within the normal range. It is concluded that 20 mg simvastatin was more effective than 16 g cholestyramine in the treatment of hypercholesterolaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effects of simvastatin and fenofibrate on serum lipoproteins and apolipoproteins in primary hypercholesterolaemia.

Sixteen patients with primary hypercholesterolaemia received double-blind either fenofibrate (n = 8; 200 mg bid) or the HMG-CoA reductase inhibitor simvastatin (n = 8; 20 mg q.p.m. [corrected] or 40 mg q.p.m. [corrected] if LDL-cholesterol did not fall below 3.6 mmol.l-1 after 4 weeks of treatment). Simvastatin reduced total cholesterol from 9.7 to 7.0 mmol.l-1 after 10 weeks (-28%), and fenofibrate reduced it from 9.2 to 7.7 mmol.l-1 (-15%). The decrease was less during fenofibrate than during simvastatin treatment (time x drug: p = 0.02). Serum LDL-cholesterol fell from 8.3 to 5.3 mmol.l-1 (-36%) during simvastatin and from 7.2 to 6.0 mmol.l-1 (-16%) during fenofibrate administration. Again, the effect of simvastatin was more pronounced than that of fenofibrate (time x drug: p = 0.03). HDL-cholesterol increased significantly from 1.1 to 1.2 mmol.l-1 (+13%) during fenofibrate administration and it did not change significantly during simvastatin. Serum triglycerides fell from 1.3 to 1.1 mmol.l-1 (-16%) during simvastatin, and even more significantly from 2.2 to 1.1 mmol.l-1 (-51%) during fenofibrate (time x drug: p = 0.002). Apolipoprotein B fell on simvastatin from 1.9 to 1.4 g.l-1 (-24%) and from 1.8 to 1.4 g.l-1 (-22%) during fenofibrate. Both drugs were well tolerated and had no significant adverse effects. Simvastatin lowered total and LDL-cholesterol concentrations more than fenofibrate, while the latter had more effect on triglycerides, suggesting specific indications for the two drugs in the treatment of hyperlipoproteinaemias.

Adult↗

Lipoprotein particle analysis comparing simvastatin and fenofibrate.

This study compares the effects of fenofibrate and simvastatin in primary hypercholesterolemia, with particular regard to lipoprotein particles, as defined by their apolipoprotein composition: LpAI, LpAII: AI, LpE:B, LpCIII:B. This was a double-blind study in which patients were randomized to 2 groups, one receiving simvastatin 20 mg once daily and the other receiving fenofibrate 200 mg b.i.d., if their total cholesterol and their LDL cholesterol remained above 7.60 mmol/l (300 mg/dl) and 4.95 mmol/l (195 mg/dl) after a 4-week placebo period. Simvastatin dosage was doubled at the end of 6 weeks of therapy if the LDL-cholesterol level remained above 3.55 mmol/l (140 mg/dl). Analyses were done after 6 and 10 weeks of therapy. Apolipoprotein AI was increased significantly only at week 10 with fenofibrate (+7.4%). Simvastatin had a more pronounced effect than fenofibrate on apolipoprotein B. There was a significant difference between drugs at weeks 6 and 10. No change was observed in the LpAII:AI level with simvastatin, whereas fenofibrate increased these particles quite significantly (+13.9 and +22.3%). The drugs had opposite effects on LpAI (+2.5 and +5.6% with simvastatin; -12.8 and -15.1% with fenofibrate). LP E:B (-33.0 and -40.8% with simvastatin; -53.8 and -52.2% with fenofibrate) and LpCIII:B (-23.8 and -31.8% with simvastatin; -35.1 and -43.5% with fenofibrate) were decreased by both drugs, but fenofibrate was significantly more effective in reducing these particles than simvastatin at week 6. This study suggests that both drugs led to different structural modifications of the lipoproteins, which would not be revealed by total apolipoprotein analysis. These differences are probably related to the mechanisms of action of these drugs.

Adolescent↗

Effect of simvastatin on receptor mediated metabolism of low density lipoprotein in guinea pigs.

This study examined the effects of simvastatin, an inhibitor of HMG-CoA reductase, on the metabolism of labelled human low density lipoprotein (LDL) in animal models. Administration of 10 mg/kg per day simvastatin for 2 weeks reduced the levels of total cholesterol, LDL-cholesterol and triglycerides by 5.7 mg/dl (16%), 8.8 mg/dl (36%) and 4.9 mg/dl (13%), respectively in guinea pigs. High density lipoprotein-cholesterol levels rose 0.8 mg/dl (29%) by simvastatin treatment. Measurements of turnover of LDL were determined between simvastatin-treated guinea pigs and untreated guinea pigs using intravenous injection of 131I-labelled LDL and 125I-labelled galactose-treated LDL to quantify the LDL receptor pathway. Simvastatin significantly increased the fractional catabolic rate (FCR) of the LDL receptor-dependent pathway. In contrast, the FCR of the LDL receptor-independent pathway was not altered by simvastatin therapy. The FCR for LDL isolated from simvastatin-treated subjects compared to that from control subjects was very similar in both control and simvastatin-fed guinea pigs. These findings suggest that simvastatin mainly reduced serum cholesterol levels by accelerated FCR of LDL receptor mediated pathway.

Animals↗

Simvastatin and losartan enhance nitric oxide and reduce oxidative stress in salt-induced hypertension.

BACKGROUND: The renin-angiotensin-aldosterone system and oxidative stress play a major role in the pathogenesis of hypertension. METHODS: We examined the effects of simvastatin, an HMG-CoA inhibitor, and losartan, an angiotensin type 1 receptor antagonist, in Dahl rats fed a high salt diet (8% NaCl), and treated with either simvastatin (3 mg/kg/d), losartan (10 mg/kg/d), or their combination using the drinking water as vehicle, for 3 weeks. Mean blood pressure (MAP) was measured by tail-cuff plethysmography. Plasma levels of nitric oxide (NO) and prostanoids, as well as plasma and tissue angiotensin II (Ang II) and aldosterone (ALDO) were analyzed by enzyme immunoassay. Renal and aortic superoxide production was determined by fluorescence spectrometry. Vascular reactivity of second-order mesenteric arteries was assessed in vitro. RESULTS: Simvastatin, losartan, and the drug combination attenuated the salt-induced increase in MAP. Plasma NO was elevated by simvastatin, losartan, and the combination, whereas plasma thromboxane was reduced by losartan. Simvastatin, losartan, and the combination reduced renal Ang II, but only the combination reduced cardiac Ang II. Heart and renal ALDO were reduced by simvastatin, losartan, and the combination. Aortic and renal NADPH-dependent superoxide production was reduced by simvastatin, losartan, and the combination. The response to acetylcholine, in mesenteric arteries preconstricted with norepinephrine, was greater in the losartan group. CONCLUSIONS: Thus, treatment with simvastatin and losartan lowered oxidative stress and improved endothelial function. Simvastatin significantly reduced the effect of losartan on vascular reactivity in mesenteric arteries, suggesting that their combination may be contraindicated.

Acetylcholine↗

Comparison of the impact of atorvastatin and simvastatin on apoA-I kinetics in men.

BACKGROUND: The impact of simvastatin and atorvastatin, two HMG-CoA inhibitors, on plasma HDL-C concentrations has been shown to be inconsistent, simvastatin being reported to induce greater increases in HDL-C than atorvastatin. The physiological mechanisms underlying this diverging effect are still unknown. OBJECTIVES: To compare the impact of simvastatin and atorvastatin on apoA-I kinetics in vivo. METHODS: In this double-blind, cross-over study, seven men with relatively low baseline HDL-C were assigned in random order to one of two experimental 8-week treatments (atorvastatin 40 mg or simvastatin 80 mg), each separated by a 6-week washout period. After each phase, apoA-I kinetics were measured using a primed-constant infusion of l-(5,5,5-D3) leucine for 12 h with patients being kept in constant fed, steady state. Isotopic enrichment of apoA-I over time was assessed by gas chromatography-mass spectrometry and kinetic parameters were calculated by multicompartmental modeling. RESULTS: Both treatments reduced plasma LDL-C levels to a similar extent while HDL-C levels remained statistically unchanged after both experimental phases. However, compared to atorvastatin, plasma apoA-I concentrations were significantly higher after treatment with simvastatin (1.33 +/- 0.07 g/L versus 1.23 +/- 0.07 g/L, P = 0.05). Treatment with simvastatin also induced a significant increase in apoA-I production rate compared to atorvastatin (15.2 +/- 3.0 mg/kg/d versus 13.2 +/- 2.6 mg/kg/d, P = 0.05). There was no statistical difference in apoA-1 fractional catabolic rate between simvastatin and atorvastatin (0.26 +/- 0.05 pool/d versus 0.24 +/- 0.04 pool/d). CONCLUSIONS: These results suggest that the diverging impact of simvastatin and atorvastatin on plasma HDL-C levels in humans may be attributable, at least partly, to a greater production rate of apoA-I with simvastatin.

Apolipoprotein A-I↗

Efficacy and tolerability of combined treatment with L-carnitine and simvastatin in lowering lipoprotein(a) serum levels in patients with type 2 diabetes mellitus.

Lipoprotein(a) [Lp(a)] concentration is generally related to coronary artery disease (CAD) and cerebrovascular disease. However, at present, few interventions are available to lower Lp(a) concentrations. We investigated the effects of l-carnitine, co-administered with simvastatin, on hyper-Lp(a) in patients with type 2 diabetes mellitus. We conducted an open, randomised, parallel-group study, in one investigational center (University hospital). Fifty-two patients with type 2 diabetes mellitus, a triglyceride serum levels <400mg/dL (<4.5 mmol/L), and Lp(a) serum levels >20mg/dL (0.71 mmol/L) were randomised to receive simvastatin alone (n=26) or simvastatin plus l-carnitine (n=26) for 60 days. Simvastatin was administered, in both groups, at a dosage of 20 mg/day, while l-carnitine was administered at a dosage of 2g/day once daily. Both treatments were given orally. Serum levels of triglycerides, total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL cholesterol (total cholesterol minus HDL cholesterol), apolipoprotein B, and Lp(a) were measured at baseline and 60 days after starting treatment. No difference in time by groups (simvastatin and simvastatin plus l-carnitine) were observed in the reduction of LDL cholesterol, non-HDL cholesterol, and apoB serum levels. On the other hand, Lp(a) serum levels increase from baseline to 60 days in the simvastatin group alone versus a significant decrease in the combination group. Our findings provide support for a possible role of combined treatment with l-carnitine and simvastatin in lowering Lp(a) serum levels in patients with type 2 diabetes mellitus than with simvastatin alone. Our results strongly suggest that l-carnitine may have a role among lipid-lowering strategies.

Aged↗

Simvastatin treatment partially prevents ovariectomy-induced bone loss while increasing cortical bone formation.

Statins are commonly prescribed drugs that inhibit hepatic cholesterol synthesis and thereby reduce serum cholesterol concentrations. Some of the statins are thought to possess bone anabolic properties. Effects of statin on tibia, femur, and vertebral cortical and cancellous bone were studied in ovariectomized (OVX) rats. Sixty Wistar female rats, 4 months old, were allocated into four groups: baseline control, sham + placebo group, OVX + placebo, OVX + simvastatin. Simvastatin, 20 mg/kg, or placebo was given twice daily by a gastric tube for 3 months. The rats were labeled with tetracycline at day 11 and calcein at day 4 before sacrifice. Concerning cortical bone, the tibial diaphysis bending strength was increased by 8% and the periosteal bone formation rate (BFR) at the mid-diaphysis increased by twofold in the OVX + simvastatin group compared with the OVX + placebo group, in harmony with increased serum osteocalcin concentrations. Simvastatin did not affect the endocortical bone formation. Concerning cancellous bone, the cancellous bone volumes in the proximal tibia and vertebral body were reduced in both OVX groups, but the reduction was less in the OVX + simvastatin group compared with the OVX + placebo group. This reduction in cancellous bone loss is in agreement with the 36% decreased activity of serum tartrate-resistant-acid-phosphatase 5b (TRAP-5b), indicating decreased osteoclast activity in the OVX + simvastatin group compared with the OVX + placebo group. In conclusion, simvastatin induces a moderate increase in cortical bone formation at the periosteal bone surface. The new cortical bone exhibits a normal lamellar structure, and simvastatin seems to respect the regional pattern of bone formation, bone resorption, and drift; for example, no periosteal bone formation is observed in the vertebral canal. Furthermore, simvastatin reduces the loss of cancellous bone induced by ovariectomy.

Animals↗

Comparison of midazolam and simvastatin as cytochrome P450 3A probes.

OBJECTIVE: Our objective was to compare simvastatin with the validated probe midazolam in the assessment of cytochrome P450 (CYP) 3A activity. METHODS: This study used an open-label, fixed-sequential, 3-way crossover study design. Nineteen subjects received oral doses of 0.075 mg/kg midazolam and 40 mg simvastatin during 3 phases (baseline, after inhibition with 400 mg ketoconazole for 10 days, and after induction with 600 mg rifampin [INN, rifampicin] for 9 days). Serial plasma concentrations of midazolam and simvastatin were obtained. Oral clearances of midazolam and simvastatin were compared. RESULTS: Oral midazolam clearance decreased after pretreatment with ketoconazole (from a geometric mean of 25 mL x min(-1) x kg(-1) [range, 12-57 mL x min(-1) x kg(-1)] to 2.7 mL x min(-1) x kg(-1) [range, 1.2-8.5 mL x min(-1) x kg(-1)], P < .001) and increased after pretreatment with rifampin (to a geometric mean of 203 mL x min(-1) x kg(-1) [range, 125-371 mL x min(-1) x kg(-1)], P < .001). Oral simvastatin clearance decreased after ketoconazole (from a geometric mean of 312 mL x min(-1) x kg(-1) [range, 151-1478 mL x min(-1) x kg(-1)] to 25 mL x min(-1) x kg(-1) [range, 8.0-147 mL x min(-1) x kg(-1)], P < .001) and increased after rifampin (to a geometric mean of 3536 mL x min(-1) x kg(-1) [range, 413-10,329 mL x min(-1) x kg(-1)], P < .001). The change in simvastatin clearance was highly variable from baseline to inhibition (6- to 33-fold decrease) and from baseline to induction (2- to 39-fold increase) compared with midazolam (7- to 18-fold decrease during inhibition and 4- to 12-fold increase during induction). Midazolam and simvastatin oral clearances were correlated for all study phases (r = 0.5 and P = .03 for baseline and r = 0.53 and P = .02 for inhibition) but were weakest for induction (r = -0.031, P = .22). The area under the concentration-time curve inhibitory ratio for midazolam was 9.4 versus 12.4 for simvastatin (r = 0.3, P = .03). CONCLUSIONS: Compared with midazolam, simvastatin is a nonvalidated, suboptimal probe for studying CYP3A drug interactions because of its lack of CYP3A specificity.

Administration, Oral↗

Simvastatin potentiates tumor necrosis factor alpha-mediated apoptosis of human vascular endothelial cells via the inhibition of the geranylgeranylation of RhoA.

HMG-CoA reductase inhibitors (statins) are widely used in the treatment and prevention of atherosclerosis. Here we demonstrate that the HMG-CoA reductase inhibitor simvastatin potentiates TNFalpha-mediated apoptosis and TNFalpha signaling in human umbilical vein endothelial cells (HUVECs). While 2.5 microM simvastatin or 40 ng/ml TNFalpha alone had only a small effect on apoptosis in HUVECs, co-incubation with simvastatin and TNFalpha markedly increased apoptosis in a time- and dose-dependent manner as measured by FACS analysis of propidium iodide-stained cells. Geranylgeraniol, which serves as a substrate for the geranylgeranylation of small GTP binding proteins such as RhoA, which is required for the function and membrane localization of Rho, reversed the effect of simvastatin on apoptosis. GGTI, an inhibitor of protein geranylgeranylation, mimicked the effect of simvastatin on apoptosis and interfered with the membrane localization of RhoA. Furthermore, simvastatin increased the expression of the TNFalpha type I receptor (TNFalphaRI) with a dose dependence and a dependence on geranylgeranylation similar to that demonstrated for the potentiation of TNFalpha-mediated apoptosis. Adenoviral expression of a dominant-negative RhoA mimicked the effect of simvastatin on the expression of TNFalphaRI, while adenoviral expression of a dominant-activating RhoA mutant reversed the effect of simvastatin on the expression of TNFalphaRI. Simvastatin also potentiated TNFalpha signaling as determined by increased TNFalpha-mediated E-selectin expression. These data support the conclusion that TNFalpha signaling is under the negative control of RhoA and that statins potentiate TNFalpha signaling at least in part via interference with RhoA inhibition of TNFalpha type I receptor expression.

Apoptosis↗

Comparison of efficacy and safety of atorvastatin and simvastatin in patients with dyslipidemia with and without coronary heart disease.

The efficacy and safety of atorvastatin 10 mg versus simvastatin 20 mg and atorvastatin 80 mg versus simvastatin 80 mg was determined in a 6-week, prospective, randomized, open-label, blinded end-point trial of dyslipidemic patients with and without coronary heart disease. A total of 1,732 patients with hypercholesterolemia and triglycerides < or =600 mg/dl (6.8 mmol/L) were randomized to receive either atorvastatin 10 mg (n = 650), simvastatin 20 mg (n = 650), atorvastatin 80 mg (n = 216), or simvastatin 80 mg (n = 216). The primary efficacy parameter was the change in low-density lipoprotein (LDL) cholesterol from baseline to week 6. Secondary efficacy parameters included the percent change from baseline to week 6 in total cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, very-low-density lipoprotein cholesterol, apolipoprotein B, and the percent of patients achieving their National Cholesterol Education Program (NCEP) LDL cholesterol goal at study end. Atorvastatin had significantly greater reductions from baseline in LDL cholesterol than simvastatin in both comparator groups: atorvastatin 10 mg (37.1%) versus simvastatin 20 mg (35.4%) (p = 0.0097), and atorvastatin 80 mg (53.4%) versus simvastatin 80 mg (46.7%) (p <0.0001). Atorvastatin 10 and 80 mg also provided significantly greater reductions in total cholesterol, triglycerides, very-low-density lipoprotein cholesterol, and apolipoprotein B than simvastatin 20 and 80 mg, respectively (all p <0.05). All treatment groups had a significantly decreased LDL cholesterol/HDL cholesterol ratio from baseline (all p <0.0001). In both comparator groups a higher proportion of atorvastatin-treated patients reached their NCEP LDL cholesterol goal compared with simvastatin. All 4 study treatments were well tolerated.

Adolescent↗

Simvastatin inhibits leukocyte accumulation and vascular permeability in the retinas of rats with streptozotocin-induced diabetes.

Leukocytes play important roles in the pathogenesis of diabetic retinopathy. Recently, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors have been reported to exert various effects in addition to their lipid-lowering ability. We investigated the effects of simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, on leukocyte-induced diabetic changes in retinas. Diabetes was induced in Long-Evans rats with streptozotocin, and simvastatin administration was begun immediately after the induction of diabetes. Two weeks of treatment with simvastatin suppressed significantly the number of leukocytes adhering to retinal vessel endothelium and the number of leukocytes accumulated in the retinal tissue by 72.9% and 41.0%, respectively (P < 0.01). The expression of intercellular adhesion molecule-1 (ICAM-1) and the CD18 (the common beta-chain of ICAM-1 ligands) were both suppressed with simvastatin. The amount of vascular endothelial growth factor in the retina was attenuated in the simvastatin-treated group. To evaluate the effects of simvastatin on leukocyte-induced endothelial cell damage, vascular permeability in the retina was measured with fluorescein-labeled dextran. Treatment with simvastatin markedly reduced retinal permeability (P = 0.014). This suggests that simvastatin attenuates leukocyte-endothelial cell interactions and subsequent blood-retinal barrier breakdown via suppression of vascular endothelial growth factor-induced ICAM-1 expression in the diabetic retina. Simvastatin may thus be useful in the prevention of diabetic retinopathy.

Animals↗

The effect of hormone replacement therapy alone and in combination with simvastatin on plasma lipids of hypercholesterolemic postmenopausal women with coronary artery disease.

OBJECTIVES: This study sought to compare hormone replacement therapy (HRT), simvastatin and their combination in the management of hypercholesterolemia in postmenopausal women with coronary artery disease (CAD). BACKGROUND: Lipid-lowering therapy reduces mortality in hypercholesterolemic women with CAD. In postmenopausal women HRT seems to increase survival, particularly those with ischemic heart disease, and this is partly due to changes in lipid levels. METHODS: We studied 16 postmenopausal women with CAD and fasting total cholesterol <200 mg/dl and low-density lipoprotein (LDL) cholesterol <130 mg/dl. We compared HRT (0.625 mg of conjugated estrogen and 2.5 mg of medroxyprogesterone acetate daily) with simvastatin (20 mg daily) and their combination in a randomized, crossover, placebo-controlled study. Each treatment period was 8 weeks long with a 4-week washout interval between treatments. RESULTS: Simvastatin, HRT and their combination significantly reduced total and LDL cholesterol by 35%, 13%, and 33% and 45%, 20%, and 46%, respectively, compared to placebo (p < 0.001). However, simvastatin and the combination was superior to HRT (p < 0.001), and none of our patients had total cholesterol <180 mg/dl and LDL cholesterol <100 mg/dl on HRT alone. High-density lipoprotein cholesterol was not significantly affected by any of the active treatments, and triglycerides were lower during simvastatin therapy compared to placebo (p < 0.01). Apolipoprotein B was significantly reduced by simvastatin, alone and combined with HRT, by 39% and 35%, respectively, compared to placebo (p < 0.001). Alone and in combination with simvastatin, HRT significantly increased apolipoprotein A-I by 11% and 12%, respectively, compared to placebo (p < 0.05) and decreased lipoprotein (a) by 23% and 33%, respectively, compared to placebo (p < 0.05), whereas simvastatin had no significant effect on either of these parameters. CONCLUSIONS: In hypercholesterolemic postmenopausal women with CAD, HRT exerts beneficial effects on plasma lipids but the levels currently recommended for secondary prevention are not achieved. Hormone replacement therapy combined with simvastatin is well tolerated and extremely effective, as the two therapies seem to be additive.

Aged↗

Characterization of endothelial factors involved in the vasodilatory effect of simvastatin in aorta and small mesenteric artery of the rat.

1. Vascular effects of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, simvastatin, were studied in conductance (aorta) and resistance vessels (branch II or III of superior mesenteric artery, SMA) of the rat (12 - 14 weeks old). 2. Simvastatin produced relaxation of both aorta and SMA, with and without functional endothelium. These responses were inhibited by the product of HMG-CoA reductase, mevalonate (1 mmol l(-1)). 3. In vessels with functional endothelium, the NO-synthase inhibitor, L-N(G)-nitroarginine (L-NOARG, 30 micromol l(-1)), inhibited simvastatin-induced relaxation. In the presence of L-NOARG, relaxation to simvastatin was lower in vessels with endothelium than in endothelium-denuded arteries without L-NOARG. 4. The cyclo-oxygenase inhibitor, indomethacin (10 micromol l(-1)), abolished endothelium-dependent component of the response to simvastatin in both arteries. The combination of L-NOARG plus indomethacin did not produce further inhibition. The T(p) receptor antagonist, GR 32191B (3 micromol l(-1)), did not affect relaxation in aorta but it reduced response to low concentrations of simvastatin in SMA. However, the inhibitory effect of L-NOARG was less marked in the presence of GR 32191B in aorta but not in SMA. 5. The endothelium-dependent relaxation to simvastatin was inhibited by the superoxide dismutase (SOD, 100 u ml(-1)) or by the tyrosine kinase inhibitor, genistein (30 micromol l(-1)) in the two arteries. 6. The present study shows that simvastatin produces relaxation of conductance and small arteries through mevalonate-sensitive pathway. The endothelium-dependent relaxation to simvastatin involves both NO and vasodilator eicosanoids by a mechanism sensitive to SOD, and to genistein. Also, the results highlighted participation in the aorta of endothelial vasoconstrictor eicosanoids acting on the T(p) receptor after blockage of NO synthase only.

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