Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatocyte nuclear factor 1 alpha (HNF1alpha) is a liver enriched homeodomain-containing transcription factor that has been shown to transactivate the promoters of several cytochrome P450 (CYP) genes, including CYP2E1, CYP1A2, CYP7A1, and CYP27, in vitro. In humans, mutations in HNF1alpha are linked to the occurrence of maturity onset diabetes of the young type 3, an autosomal dominant form of non-insulin-dependent diabetes mellitus in which afflicted subjects generally develop hyperglycemia before 25 years of age. Mice lacking HNF1alpha also develop similar phenotypes reminiscent of non-insulin-dependent diabetes mellitus. To investigate a potential role for HNF1alpha in the regulation of CYPs in vivo, the expression of major CYP genes from each family was examined in the livers of mice lacking HNF1alpha. Analysis of CYP gene expression revealed marked reductions in expression of Cyp1a2, Cyp2c29 and Cyp2e1, and a moderate reduction of Cyp3a11. In contrast Cyp2a5, Cyp2b10 and Cyp2d9 expression were elevated. There are also significant changes in the expression of genes encoding CYPs involved in fatty acid and bile acid metabolism characterized by a reduction in the expression of Cyp7b1, and Cyp27 as well as elevations in Cyp4a1/3, Cyp7a1, Cyp8b1, and Cyp39a1 expression. These results point to a critical role for HNF1alpha in the regulation of CYPs in vivo and suggest that this transcription factor may have an important influence on drug metabolism as well as lipid and bile acid homeostasis in maturity onset diabetes of the young type 3 diabetics.
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PMID:Hepatic expression of cytochrome P450s in hepatocyte nuclear factor 1-alpha (HNF1alpha)-deficient mice. 1459 59

Dyslipidemia, characterized by elevated serum levels of triglycerides and reduced levels of total cholesterol, low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol, has been recognized in patients with human immunodeficiency virus (HIV) infection. It is thought that elevated levels of circulating cytokines, such as tumor necrosis factor-alpha and interferon-alpha, may alter lipid metabolism in patients with HIV infection. Protease inhibitors, such as saquinavir, indinavir and ritonavir, have been found to decrease mortality and improve quality of life in patients with HIV infection. However, these drugs have been associated with a syndrome of fat redistribution, insulin resistance, and hyperlipidemia. Elevations in serum total cholesterol and triglyceride levels, along with dyslipidemia that typically occurs in patients with HIV infection, may predispose patients to complications such as premature atherosclerosis and pancreatitis. It has been estimated that hypercholesterolemia and hypertriglyceridemia occur in greater than 50% of protease inhibitor recipients after 2 years of therapy, and that the risk of developing hyperlipidemia increases with the duration of treatment with protease inhibitors. In general, treatment of hyperlipidemia should follow National Cholesterol Education Program guidelines; efforts should be made to modify/control coronary heart disease risk factors (i.e. smoking; hypertension; diabetes mellitus) and maximize lifestyle modifications, primarily dietary intervention and exercise, in these patients. Where indicated, treatment usually consists of either pravastatin or atorvastatin for patients with elevated serum levels of LDL-C and/or total cholesterol. Atorvastatin is more potent in lowering serum total cholesterol and triglycerides compared with other hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, but it is also associated with more drug interactions compared with pravastatin. Simvastatin and lovastatin are significantly metabolized by cytochrome P450 enzymes (CYP3A4) and are therefore not recommended for coadministration with protease inhibitors. A fibric acid derivative (gemfibrozil or fenofibrate) should be used in patients with primary hypertriglyceridemia. However, it must be kept in mind that protease inhibitors, such as nelfinavir and ritonavir, induce enzymes involved in the metabolism of the fibric acid derivatives and may, therefore, reduce the lipid-lowering activity of coadministered gemfibrozil or fenofibrate. In certain patients HMG-CoA reductase inhibitors may be used in combination with fibric acid derivatives but patients should be carefully monitored for liver and skeletal muscle toxicity. Select patients may experience improvements in serum lipid levels when their offending protease inhibitor(s) is/are exchanged for efavirenz, nevirapine, or abacavir; however each patient's virologic and immunologic status must be taken closely into consideration.
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PMID:Management of protease inhibitor-associated hyperlipidemia. 1472 85

Our initial studies on renal cyclooxygenase (COX)-2 expression and activity addressed the critical role of angiotensin II (Ang II) in increasing tumor necrosis factor alpha (TNF) that eventuated in expression of COX-2 in the medullary thick ascending limb (mTAL) of the nephron. COX-2 supplanted the dominant oxygenase, the cytochrome P450 (CYP) enzyme, omega-hydroxylase, that synthesized 20-hydroxyeicosatetraenoic acid (20-HETE). These findings served as the basis for additional studies on: 1) the role of glucocorticoids in regulating COX-2 expression and activity in the mTAL; and 2) the utilization of the same signaling pathways in response to stimulation of the mTAL calcium receptor (CaR). These studies of mTAL COX-2 expression which are addressed in the first part of this chapter are followed by explorations of the expression of COX-2 in preglomerular microvessels (PGMV) and the relationship of COX-2 to 20-HETE, the principal eicosanoid of PGMV. The third and last component of this chapter explores the signaling events, focusing on COX-2, which are set in motion by diabetes.
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PMID:Renal COX-2, cytokines and 20-HETE: tubular and vascular mechanisms. 1496 24

CYP2E1 and CYP4A11 are cytochrome P450 enzymes that are regulated by physiological conditions including diabetes and fasting. In addition, the xenochemical clofibrate has been reported to induce both rodent CYP2E1 and CYP4A. These findings suggest similar modes of regulation. Also in common to both enzymes is the ability to metabolize fatty acids such as laurate and arachidonic acid. Here, we used primary cultures of human hepatocytes to determine if certain xenochemicals could regulate CYP2E1 and CYP4A11. Ethanol significantly (p < 0.05) increased expression of CYP2E1 mRNA by 216 +/- 32% of control, but did not alter CYP4A11 mRNA accumulation (145 +/- 22% of control). In contrast, hepatocytes exposed to ethanol exhibited only a slight elevation in CYP2E1 protein (122 +/- 13% of control) and a negligible effect on CYP4A11 protein. Clofibrate significantly (p < 0.05) enhanced both CYP4A11 mRNA and protein by 239 +/- 30% and 154 +/- 10% of control, respectively, but did not increase CYP2E1. Because rodent CYP4A is reportedly regulated by fatty acids through peroxisome proliferator activated receptor alpha (PPARalpha) and CYP2E1 is induced by high fat diets, we examined the effects of a medium chain fatty acid, palmitate on CYP2E1 mRNA content. Palmitic acid significantly (p < 0.05) increased CYP2E1 mRNA to 326 +/- 57% of control. Collectively, results presented here identify agents that enhance CYP2E1 and CYP4A11 at the transcription level and suggest that fatty acids may represent a similar mode of regulation for these P450 enzymes. The lack of induction of CYP2E1 protein by ethanol in human hepatocytes indicates that for certain P450 enzymes, isolated hepatocytes may not be an adequate tool for predicting in vivo responses.
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PMID:Regulation of CYP2E1 by ethanol and palmitic acid and CYP4A11 by clofibrate in primary cultures of human hepatocytes. 1505 2

Repaglinide (Prandin), NovoNorm, GlucoNorm, an oral insulin secretagogue, was the first meglitinide analogue to become available for use in patients with type 2 diabetes mellitus. The drug lowers postprandial glucose excursions by targeting early-phase insulin release, an effect thought to be important in reducing long-term cardiovascular complications of diabetes. Repaglinide provided similar overall glycaemic control to that achieved with glibenclamide (glyburide), as assessed by glycosylated haemoglobin (HbA(1c)) and fasting blood glucose levels, and was generally well tolerated in well designed clinical trials. Its rapid onset and relatively short duration of action allow for flexible meal schedules. Two modelled US cost-effectiveness analyses projected lifetime costs and outcomes for a hypothetical cohort of patients with type 2 diabetes. Both analyses projected long-term complications using data on HbA(1c) level changes from short-term clinical trials. Repaglinide plus rosiglitazone was dominant over rosiglitazone in one analysis, and repaglinide plus metformin was dominant over nateglinide plus metformin in the other. A similar Canadian analysis showed a favourable incremental cost-effectiveness ratio (<dollars US 1000 per QALY gained; 2001 values) for patients who switched from a sulphonylurea to repaglinide versus those who remained on sulphonylurea therapy. Long-term outcomes were projected using short-term clinical trial data on postprandial blood glucose level changes in the Canadian study. All three cost-effectiveness analyses are available as abstracts/posters. Two US cost analyses (both published in full) have also been conducted comparing the short-term costs (<or=3 years) of repaglinide, with or without metformin, versus other oral antidiabetic regimens. Results of these analyses are somewhat equivocal because of study design issues and/or a lack of statistically significant differences between treatment groups. In conclusion, repaglinide as monotherapy or in combination with other antidiabetic agents, such as metformin or rosiglitazone, achieves good metabolic control, similar to that achieved with comparable glibenclamide regimens. Severe hypoglycaemic episodes are less common with repaglinide than some sulphonylureas, including glibenclamide. Modelled cost-effectiveness analyses conducted in North America showed favourable results for repaglinide-containing regimens versus comparators, largely attributed to projected reductions in long-term cardiovascular complications using short-term data on changes in glycaemic parameters from clinical trials. Results of these cost-effectiveness analyses (all of which have been published as abstracts/posters) should be interpreted with caution since various assumptions regarding long-term costs and outcomes were necessarily incorporated into the economic models. While repaglinide is a useful addition to the available treatment options in type 2 diabetes, potential long-term advantages versus other agents, such as reducing cardiovascular complications, require confirmation. The prevalence of diabetes mellitus is projected to increase to over 3% of the world's population ( approximate, equals 220 million people) by the year 2010. Globally, 97% of patients with diabetes have type 2 disease, although in industrialised countries the proportion of type 2 disease is about 90%. In 2010, an estimated 14.85 million individuals in the US and 2.88 million in the UK will be diagnosed with type 2 diabetes. In addition, approximately one-third to one-half of individuals with diabetes are unaware that they have the disease, and are therefore undiagnosed. Diabetes is associated with significant morbidity, mortality and economic consequences. For the year 2002 in the US, direct medical costs associated with diabetes (type 1 and 2) were estimated at dollars US 91.8 billion (70% of total costs) and indirect costs at dollars US 39.8 billion (30%), for a total of dollars US 132 billion. Data from more than 7000 patients in eight European countries indicate tha the mean cost per patient with diabetes was dollars US 2928 annually (1999 values), and the proportion of total healthcare expenditure directed toward diabetes ranged from 1.6% to 6.6% depending on the country. Several analyses focusing specifically on type 2 disease showed, not surprisingly, that costs were higher among patients with diabetic complications than in those without complications. Repaglinide, a meglitinide analogue, is an oral insulin secretagogue that reduces postprandial glucose excursions by targeting postprandial insulin release. In clinical trials in patients with type 2 diabetes, repaglinide was usually administered at a dosage of 0.5-4 mg three times daily before meals as monotherapy or in combination with other agents. In placebo-controlled trials of up to 24 weeks' duration in patients with type 2 diabetes, repaglinide achieved statistically significant improvements in glycaemic control, as assessed by glycosylated haemoglobin (HbA(1c)), fasting blood glucose (FBG) and/or postprandial blood glucose (PPBG) levels compared with placebo. Preprandial administration of repaglinide achieved similar glycaemic control to glibenclamide (glyburide) 1.75-15 mg/day and better glycaemic control than glipizide 5-15 mg/day in 1-year, double-blind, randomised trials in patients with type 2 disease, the vast majority of whom had previously received oral antidiabetic therapy. Several randomised, open-label studies have evaluated repaglinide as part of combination therapy over 3-6 months in patients with type 2 diabetes who had inadequate glycaemic control with previous drug therapy. In general, results showed statistically significant improvements in glycaemic control when repaglinide was used in combination with metformin, various thiazolidinediones, or metformin plus bedtime insulin compared with monotherapy with either comparator drug in each study (or metformin plus bedtime insulin in one trial). Other studies in this patient population indicate that metformin plus repaglinide is associated with significantly better glycaemic control than metformin plus nateglinide 60-120 mg three times daily over 16 weeks, and similar glycaemic control to that achieved with metformin in combination with either glibenclamide or glimepiride for up to 1 year. Good glycaemic control has also been achieved with preprandial administration of repaglinide in flexible meal schedules. This was demonstrated in a placebo-controlled trial and in a large, prospective survey of patients receiving repaglinide in a clinical setting. The tolerability profile of repaglinide is characterised by adverse events of mild-to-moderate intensity similar to those associated with sulphonylureas. The most frequently reported adverse events with repaglinide include hypoglycaemia, upper respiratory infection, headache, other respiratory events, musculoskeletal events and gastrointestinal events. Severe episodes of hypoglycaemia are rare with repaglinide and occur approximately 2-2.5 times less frequently than with sulphonylureas. In addition, available data indicate that repaglinide may be less likely to increase bodyweight than various commonly used sulphonylurea agents. In general, repaglinide is also well tolerated when used as part of combination therapy. Repaglinide is metabolised by the cytochrome P450 (CYP) 3A4 enzyme system and therefore has the potential to interact with other CYP3A4 substrates when administered concurrently. A number of studies in healthy volunteers have shown no clinically significant pharmacokinetic drug interactions when repaglinide was administered concomitantly with digoxin, theophylline, warfarin, cimetidine, ketoconazole, rifampicin (rifampin), ethinylestradiol, simvastatin or nifedipine. However, a clinically significant increase in systemic exposure to repaglinide occurs when clarithromycin and repaglinide are administered concurrently, which may necessitate a reduction in repaglinide dosage. Moreover, a potentially hazardous interaction occurs when gemfibrozil (alone or with itraconazole) is used concomitantly with repaglinide. In view of the marked increase in systemic exposure to repaglinide, the combination of repaglinide and gemfibrozil should be avoided if possible. Pharmacoeconomic Analyses of RepaglinideTwo US cost analyses have been conducted with repaglinide in patients with type 2 diabetes (both published in full). One was a retrospective analysis of pharmacy and medical claims data from a large managed care organisation in which costs were adjusted for age, gender and comorbidities. Total adjusted (year 2000) cost per patient over a 9-month period was numerically lower for those treated with a combination of repaglinide plus metformin (dollars US 8924) than for patients who received metformin only (dollars US 9448), metformin plus glibenclamide (dollars US 9576) or repaglinide only (dollars US 11910), although there were no statistically significant differences between treatment groups. The other study, a literature-based decision-tree analysis, projected the proportion of patients achieving a target HbA(1c) level (<7%) and the associated direct medical costs over a 3-year period from the time of diagnosis. Among six different treatment regimens evaluated, costs ranged from dollars US 6106 with glipizide gastrointestinal therapeutic system (GITS) to dollars US 9298 with repaglinide monotherapy (2001/2002 values). Probabilistic sensitivity analysis indicated that first-line therapy with glipizide GITS or metformin would be associated with lower total medical costs than rosiglitazone or repaglinide monotherapy. Three cost-effectiveness analyses, all of which are modelled studies published as abstracts and/or posters, have been conducted with repaglinide in patients with type 2 diabetes. (ABSTRACT TRUNCATED)
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PMID:Repaglinide : a pharmacoeconomic review of its use in type 2 diabetes mellitus. 1509 24

The liver steatosis is a frequent human disease. The most frequent cause of the process is the alcohol consumption. But it also may arise without significant alcohol abuse. This pathogenetic process is called non-alcoholic steatohepatitis (NASH), that is characterized by the same conditions like the alcoholic steatohepatitis. In the pathogenesis of the NASH various factors participate i.e. obesity, diabetes mellitus type II, hyperlipidaemia, pregnancy, variable chemotoxins, parenteral nutrition, jejunoileal bypass, chronic inflammatory diseases, protein deficient nutrition and inborn metabolic diseases. Pathobiochemically the process consists of oxidative stress and lipid peroxidation. This condition comes from the progressive accumulation of the free fatty acids in mitochondria and from the induction of cytochrome P450, CYP 2E1 isoform in hepatocytes and Kupffer cells. The free fatty acids and ketons can cause the induction of CYP 2E1 system, that is why diabetes mellitus and obesity are the two most important factors in the NASH pathogenesis. This article is concerned mainly in the explanation of NASH pathomechanism.
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PMID:[Role of lipid peroxidation in non-alcoholic steatohepatitis]. 1511 15

Lipophilic environmental pollutants are often stored in adipose tissues after exposure. These compounds have been well studied in terms of their cell toxicity in organs such as liver and kidney, and their xenoestrogenic action on reproductive tissues as endocrine disruptors. However, the effects of these chemicals on the depot, adipose tissue, have not been studied, although adipose tissue is an important endocrine tissue secreting obesity/diabetes-related hormones and cytokines. In this study, we identified the expression of cytochromes P450 in rat white adipose tissues and investigated the effects of typical lipophilic cytochrome P450 inducers, namely phenobarbital, dexamethasone, and beta-naphthoflavone. The results showed that beta-naphthoflavone was a strong CYP1A inducer in adipose tissue as well as in liver. It increased CYP1A1 mRNA, protein, and its related activity, ethoxyresorufin O-deethylase. Phenobarbital and dexamethasone also induced both the mRNA and protein of CYP2Bs and CYP3As, respectively, in adipose tissue, although significant interindividual differences were observed. Furthermore, we demonstrated that 48 h of fasting was as effective in adipose tissue as in the liver in the induction of CYP2E1 mRNA and protein. These results suggest that the mechanisms by which cytochrome P450 genes are regulated in the liver are also functional in rat adipose tissues. This has raised the possibility that lipophilic environmental contaminants accumulated in adipose tissue may dysregulate the gene expression profile.
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PMID:Expression and induction of cytochromes p450 in rat white adipose tissue. 1515 Mar 16

Smallanthus sonchifolius (yacon), originating from South America, has become popular in Japan and in New Zealand for its tubers which contain beta-1,2-oligofructans as the main saccharides. The plant is also successfully cultivated in Central Europe in the Czech Republic in particular. Its aerial part is used in Japan and in Brazil as a component in medicinal teas; while aqueous leaf extracts have been studied for their hypoglycemic activity in normal and diabetic rats. We have already demonstrated the high content of phenolic compounds in yacon leaf extracts and their in vitro antioxidant activity. In this paper, we present the effects of two organic fractions and two aqueous extracts from the leaves of S. sonchifolius on rat hepatocyte viability, on oxidative damage induced by tert-butyl hydroperoxide (t-BH) and allyl alcohol (AA), and on glucose metabolism and their insulin-like effect on the expression of cytochrome P450 (CYP) mRNA. All the extracts tested exhibited strong protective effect against oxidative damage to rat hepatocyte primary cultures in concentrations ranging from 1 to 1000 microg/ml, reduced hepatic glucose production via gluconeogenesis and glycogenolysis at 1000 microg/ml. Moreover, the effects of the organic fractions (200 and 250 microg/ml) and to a lesser extent, the tea infusion (500 microg/ml) on rat CYP2B and CYP2E mRNA expression, were comparable to those observed with insulin. The combination of radical scavenging, cytoprotective and anti-hyperglycemic activity predetermine S. sonchifolius leaves for use in prevention and treatment of chronic diseases involving oxidative stress, particularly diabetes.
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PMID:The effect of Smallanthus sonchifolius leaf extracts on rat hepatic metabolism. 1524 86

Oxidation of ethanol via alcohol dehydrogenase (ADH) explains various metabolic effects of ethanol but does not account for the tolerance. This fact, as well as the discovery of the proliferation of the smooth endoplasmic reticulum (SER) after chronic alcohol consumption, suggested the existence of an additional pathway which was then described by Lieber and DeCarli, namely the microsomal ethanol oxidizing system (MEOS), involving cytochrome P450. The existence of this system was initially challenged but the effect of ethanol on liver microsomes was confirmed by Remmer and his group. After chronic ethanol consumption, the activity of the MEOS increases, with an associated rise in cytochrome P450, especially CYP2E1, most conclusively shown in alcohol dehydrogenase negative deer mice. There is also cross-induction of the metabolism of other drugs, resulting in drug tolerance. Furthermore, the conversion of hepatotoxic agents to toxic metabolites increases, which explains the enhanced susceptibility of alcoholics to the adverse effects of various xenobiotics, including industrial solvents. CYP2E1 also activates some commonly used drugs (such as acetaminophen) to their toxic metabolites, and promotes carcinogenesis. In addition, catabolism of retinol is accelerated resulting in its depletion. Contrasting with the stimulating effects of chronic consumption, acute ethanol intake inhibits the metabolism of other drugs. Moreover, metabolism by CYP2E1 results in a significant release of free radicals which, in turn, diminishes reduced glutathione (GSH) and other defense systems against oxidative stress which plays a major pathogenic role in alcoholic liver disease. CYP1A2 and CYP3A4, two other perivenular P450s, also sustain the metabolism of ethanol, thereby contributing to MEOS activity and possibly liver injury. CYP2E1 has also a physiologic role which comprises gluconeogenesis from ketones, oxidation of fatty acids, and detoxification of xenobiotics other than ethanol. Excess of these physiological substrates (such as seen in obesity and diabetes) also leads to CYP2E1 induction and nonalcoholic fatty liver disease (NAFLD), which includes nonalcoholic fatty liver and nonalcoholic steatohepatitis (NASH), with pathological lesions similar to those observed in alcoholic steatohepatitis. Increases of CYP2E1 and its mRNA prevail in the perivenular zone, the area of maximal liver damage. CYP2E1 up-regulation was also demonstrated in obese patients as well as in rat models of obesity and NASH. Furthermore, NASH is increasingly recognized as a precursor to more severe liver disease, sometimes evolving into "cryptogenic" cirrhosis. The prevalence of NAFLD averages 20% and that of NASH 2% to 3% in the general population, making these conditions the most common liver diseases in the United States. Considering the pathogenic role that up-regulation of CYP2E1 also plays in alcoholic liver disease (vide supra), it is apparent that a major therapeutic challenge is now to find a way to control this toxic process. CYP2E1 inhibitors oppose alcohol-induced liver damage, but heretofore available compounds are too toxic for clinical use. Recently, however, polyenylphosphatidylcholine (PPC), an innocuous mixture of polyunsaturated phosphatidylcholines extracted from soybeans (and its active component dilinoleoylphosphatidylcholine), were discovered to decrease CYP2E1 activity. PPC also opposes hepatic oxidative stress and fibrosis. It is now being tested clinically.
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PMID:The discovery of the microsomal ethanol oxidizing system and its physiologic and pathologic role. 1555 33

Simvastatin is a long-established hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, first introduced in 1988. At the maximal recommended dose of 80 mg/day, it produces an average reduction in low-density lipoprotein cholesterol (LDL-C) of 47%, accompanied by reductions in very LDL-C, triglycerides and apolipoprotein B, and a modest increase in high-density lipoprotein cholesterol. The only important, although rare, adverse effect of simvastatin is myopathy, an effect shared by all members of the class; when severe, this can take the form of rhabdomyolysis, which may lead to acute renal failure. The mechanism of the myopathy is not understood. The risk is increased by certain concomitant drugs, including gemfibrozil and potent inhibitors of cytochrome P450 3A4. Simvastatin has been studied in two large outcome trials, the Scandinavian Simvastatin Survival Study (4S), and the Heart Protection Study (HPS), both of which demonstrated strikingly beneficial effects on a variety of cardiovascular outcomes, with minimal adverse effects. 4S was the first study with a cholesterol-lowering agent to demonstrate an unequivocal reduction in all-cause mortality (30%; p = 0.0003). HPS showed that the beneficial effects of simvastatin were obtainable in a broad array of patients with, or at high risk of, coronary heart disease (CHD) in categories previously little studied, including women, the elderly, patients with diabetes without known CHD, and, perhaps most importantly, patients with LDL-C well below the UK population average. Simvastatin has recently become available in many countries as a combination product with the cholesterol absorption inhibitor, ezetimibe. Because of its long record of safety and demonstrated ability to reduce cardiovascular risk, simvastatin has recently become available without a prescription in the UK at the 10 mg dosage level.
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PMID:Simvastatin: a review. 1557 75


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