Safety review of combination drugs for hyperlipidemia

INTRODUCTION: Despite statin monotherapy, many high-risk patients are not at recommended low-density lipoprotein cholesterol goals. Moreover, these patients are also likely to exhibit an atherogenic dyslipidemia characterized by decreased high-density lipoprotein cholesterol and elevated triglycerides. As a consequence, combination lipid-altering drug therapies are frequently required to improve the lipid profile. The long-term safety and tolerability of these combination therapies are key determinants for good compliance and cardiovascular benefits. AREAS COVERED: This review summarizes the safety data published on combination drugs for the treatment of hyperlipidemia by examining the various combinations with a statin and also the other combination therapies used when statin treatment is not tolerated. The reader will gain insight into the incidence and severity of the major adverse events expected with combination therapies and the recommendations on the use of these combined treatments. A specific focus is made on muscle-related side effects. EXPERT OPINION: The existing data suggest that ezetimibe, bile acid sequestrants and ω-3 fatty acids appear unlikely to increase the risk of adverse events, particularly myopathy, when used in combination with a statin, even with a high-dose statin. Although the combination of niacin or fenofibrate with moderate-dose statins appears to be safe, prescribing a combination of these drugs with high-dose statins needs caution and requires giving careful information to the patient.     

Fibrate therapy in the management of dyslipidemias,alone and in combination with statins: role of delayed-release fenofibric acid

Importance of the field: Optimization of lipid management is a crucial aspect in the treatment of cardiovascular disease. Currently, HMG-CO reductase inhibitors (statins) are a mainstay of therapy. While this class of drugs has proven efficacy at lowering low-density lipoprotein cholesterol (LDL-C), their effects on other important lipid parameters, such as high-density lipoprotein cholesterol (HDL-C) and triglycerides, are less robust.

Areas covered in this review: The current paper will address the significance of these secondary targets and review currently available therapies, including a new formulation of delayed-release fenofibric acid. A comprehensive MEDLINE search (1966 to September 2009) was performed.

What the reader will gain: The reader will gain a comprehensive review of the importance of secondary cholesterol targets, as well as the effectiveness of currently available therapies to address non-LDL-C. The role of the newly released fenofibric acid will also be addressed, as well as its potential use in combination therapy with a statin.

Take home message: Adequate treatment of lipid parameters beyond LDL-C is an essential component in the treatment of dyslipidemia. The fibrate class of drugs has proven efficacy in improving secondary targets; however, concerns regarding severe myopathy and rhabdomyolysis have limited their combination with statins. Recently, a new fibrate derivative, fenofibric acid, has become available. Studies to date reflect a positive safety and tolerability profile when combined with statins. This may offer a new tool to address the important secondary cholesterol targets that are becoming increasingly recognized as important contributors to cardiovascular outcomes.     

Impact of SLCO1B1 (OATP1B1) and ABCG2 (BCRP) genetic polymorphisms and inhibition on LDL-C lowering and myopathy of statins

1. Statins are the preferred class of drugs for treating patients with atherosclerosis and related coronary heart disease. Treatment with statins leads to significant low-density lipoprotein cholesterol (LDL-C) lowering, resulting in reductions in major coronary and vascular events. Statins are generally well tolerated and safe; however, their use is complicated by infrequent, but often serious, muscular adverse events.

2. For many statins, both efficacy and risk of adverse muscle events can be influenced by membrane transporters, which are important determinants of statin disposition. Genetic polymorphisms and drug–drug interactions (DDIs) involving organic anion-transporting polypeptide 1B1 and breast cancer resistance protein have shown the capacity to reduce the activity of these transporters, resulting in changes in LDL-C lowering by statins, as well as changes in the frequency of adverse muscle events associated with their use.

3. This review presents evidence for how reduced transporter activity impacts the safety and pharmacology of statins. It expands on the scope of other recent statin reviews by providing recommendations on in vitro evaluation of statin interaction potential, discussing how reduced transporter activity impacts statin management during drug development, and proposing ideas on how to evaluate the impact of DDI on statin efficacy during clinical trials. Furthermore, the potential clinical consequences of perturbing statin efficacy via DDI are discussed.

     

Emerging drugs for hyperlipidemia

Importance of the field: Elevated concentrations of low-density lipoprotein (LDL) cholesterol are associated with increased risk of coronary atherosclerosis, and morbidity and mortality from coronary heart disease (CHD). Lowering of LDL cholesterol leads to a reduction in cardiovascular morbidity and all-cause mortality in individuals at risk for cardiovascular events and patients with established CHD. The mainstays of lipid lowering therapy today are the HMG-CoA reductase inhibitors (statins); however, the residual risk of cardiovascular events amongst individuals treated with statins remains a major healthcare concern.

Areas covered in this review: Emerging targets for lipid lowering therapy target pathways that regulate lipoprotein assembly, lipoprotein clearance and pro-atherogenic lipoprotein modification. These emerging drugs have novel mechanisms that include inhibition of lipoprotein assembly (antisense mRNA inhibitors of apolipoprotein B and microsomal transfer protein inhibitors), enhanced lipoprotein clearance (proprotein convertase subtilisin kexin type 9, thyroid hormone analogues), inhibition of pro-atherogenic lipoprotein remodeling (cholesterol ester transfer protein inhibitors (dalcetrapib, anacetrapib) and peroxisome proliferator activator agents (GFT-505, aleglitazar)) and inhibition of lipoprotein modification (heme oxygenase-1 inhibitor (succinobucol), phospholipase A₂ inhibitors (varespladib, darapladib)).

What the reader will gain: A review of the most recent data on emerging drugs in the treatment of hyperlipidemia.

Take home message: With these medications, we will achieve more effective reductions in cardiovascular morbidity and mortality than achieved with current lipid lowering therapies.     

Perioperative statin therapy

Introduction: The lipid lowering class of drugs known as “Statins” are being increasing recognized for their pleiotropic effects which include anti-inflammation, antioxidant, vasodilatation, improved endothelial function and stabilization of atherosclerotic plaques. These effects may counteract, to some extent, the deleterious impact of surgical stress on various organ systems during the perioperative period.

Areas covered: A literature review was undertaken to examine current evidence for the effect of perioperative statin use on postoperative morbidity and mortality. A search of PubMed, Medline and Scopus databases was performed using a combination of search terms including statins and perioperative risk reduction, outcomes, morbidity and mortality. Further searches were made on specific areas such as statins and thrombosis, kidney injury, renal protection, cancer, cost and safety.

Expert opinion: Current evidence supports a reduction in cardiovascular morbidity and mortality associated with perioperative statin use in high risk patients undergoing non cardiac surgery and this represents a very cost effective application of statin therapy with few adverse events reported. Data is emerging that point to other benefits such as renal protection but this requires further confirmation from prospective studies. Future research needs to address the questions of the optimal type, timing and dosage of statin therapy as well as whether there are problems associated with abrupt withdrawal and adverse effects associated with long term use.     

Colesevelam hydrochloride in clinical practice: a new approach in the treatment of hypercholesterolaemia

ABSTRACT

Objective: Hypercholesterolaemia is a major risk factor for atherosclerosis and coronary heart disease. Treatment with lipid lowering agents reduces the risk of vascular events. Colesevelam is a novel bile acid sequestrant (BAS) indicated for the treatment of hypercholesterolaemia, either as monotherapy or in combination with statins.

Scope: This article reviews the efficacy, tolerability and safety of colesevelam in clinical practice. The literature search was based on a PubMed search up to January 2008.

Findings: Colesevelam, used alone or in combination with other hypolipidaemic agents (statins, ezetimibe and fenofibrate), has an overall favourable effect on lipid profile. Specifically, colesevelam reduces total and low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B levels and increases high-density lipoprotein cholesterol and apolipoprotein AI. However, colesevelam may slightly raise triglyceride levels. Colesevelam can improve glycaemic control in diabetic patients. Moreover, it may have anti-inflammatory properties, as it can reduce high sensitivity C-reactive protein concentration. Colesevelam almost lacks the intense side effects of previously used BASs, thus resulting in better patient compliance. However, the dose regimen consisting of up to 7 tablets/day and high cost may limit its use.

Conclusions: Colesevelam is a safe alternative for those intolerant to other lipid lowering medication. This BAS also provides an option for patients who do not reach their LDL-C goal despite treatment with a statin.     

Combination therapy with statin and fibrate in patients with dyslipidemia associated with insulin resistance,metabolic syndrome and type 2 diabetes mellitus

Introduction: People with insulin resistance/metabolic syndrome (IR/MS) and/or type 2 diabetes mellitus (T2DM) have increased rates of cardiovascular disease (CVD) even when low-density lipoprotein cholesterol levels are at or near target levels. Contributors to this problem are the high triglyceride (TG) levels and low levels of high-density lipoprotein cholesterol (HDLC) that are commonly present in this population, even with statin therapy.

Areas covered: This review focuses on the use of a combination of statins with fibrates, which lower TG and raise HDLC concentrations and, therefore, have the potential to further lower rates of CVD more in people with IR/MS and/or T2DM. Treatment with this combination is uncommon because doctors and patients are fearful of muscle, liver and renal complications and because the evidence that the combination will actually reduce risk has been lacking. In this review, the authors examine the efficacy and safety of the statin–fibrate combination, particularly fenofibrate and simvastatin, the combination used in the ACCORD trial.

Expert opinion: The authors' opinion is that this combination of fenofibrate and statin is as safe as either drug alone and, in patients with significant dyslipidemia, is likely to reduce CVD. Concerns remain concerning fenofibrate-associated increases in serum creatinine levels and the significant heterogeneity in the reduction in CVD by the combination in women. A trial of statin + fenofibrate in people with IR/MS and/or T2DM who also have significant dyslipidemia is needed.     

The controversy of a wider statin utilization: why?

Introduction: Several medical journals published viewpoints and counter-viewpoints supporting or opposing a wider utilization of statins for primary prevention. The objective of this article is not to weigh in the benefits versus risks of statin use, but to discuss various aspects of this controversy.

Areas covered: This review discusses the challenges in examining the pleotropic effects/adverse events of statins. It also discusses the pitfalls in assessment of adverse events in randomized controlled trials and observational studies.

Expert opinion: The challenges in solving this controversy include that the pleotropic effect of statins results in an extremely wide spectrum of reported benefits or adverse events, the reported harms/benefits are contradictory, there is basic research ground supporting both sides of the controversy, it is difficult to separate if adverse events are due to statins or due to lower cholesterol, and that there is a lack of standardized definition of statin-associated adverse events and their methods of ascertainment. Both randomized controlled trials and observational studies have pitfalls and caveats in assessment of adverse events. Understanding the points of debate is of paramount significance to enable clinicians to individualize patient care.     

Statin drug interactions and related adverse reactions

Introduction: Statin monotherapy is generally well tolerated, with a low frequency of adverse events. The most important adverse effects associated with statins are myopathy and an asymptomatic increase in hepatic transaminases, both of which occur infrequently. Because statins are prescribed on a long-term basis, their possible interactions with other drugs deserve particular attention, as many patients will typically receive pharmacological therapy for concomitant conditions during the course of statin treatment.

Areas covered: This review summarizes the pharmacokinetic properties of statins and emphasizes their clinically relevant drug interactions and related adverse reactions.

Expert opinion: Avoiding drug–drug interactions and consequent adverse drug reactions is essential in order to optimize compliance, and thus improve the treatment of patients at high cardiovascular risk. The different pharmacokinetic profiles among statins should be carefully considered, in order to understand the possible spectrum of drug interactions. The growing trend toward earlier statin treatment for the prevention of cardiovascular disease means that physicians must anticipate future polypharmacy when their patients require additional medications for comorbid conditions.     

Ezetimibe/simvastatin single tablet versus rosuvastatin in patients with hypercholesterolemia

ABSTRACT

Recent guidelines recommend strict goals for low density lipoprotein cholesterol (LDL-C) (70–100?mg/dL; 1.8–2.6 mmol/L). These goals were set following the publication of several trials. In the current issue of the journal, a study compares different doses of the combination tablet (ezetimibe/simvastatin) with statin monotherapy (rosuvastatin). In keeping with previous literature, the combination therapy was more effective in achieving LDL-C goals.

This editorial comments on the potential disadvantages of using monotherapy with high-dose statins and considers the issue of statin-induced proteinuria.

Combination therapy may need to be increasingly used to achieve the LDL-C targets set by recent guidelines.     

Clinical implications of the IMPROVE-IT trial in the light of current and future lipid-lowering treatment options

Introduction: A residual risk of morbidity and mortality from cardiovascular (CV) disease remains despite statin therapy. This situation has generated an interest in finding novel approaches of combining statins with other lipid-lowering agents, or finding new lipid and non-lipid targets, such as triglycerides, high-density lipoprotein cholesterol (HDL-C), non-HDL-C, proprotein convertase subtilisin/kexin type 9 (PCSK9) gene, cholesterol ester transfer protein (CETP), lipoprotein (a), fibrinogen or C-reactive protein. Areas covered: The recent results from the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) demonstrated an incremental clinical benefit when ezetimibe, a non-statin agent, was added to simvastatin therapy. Expert opinion: The results from IMPROVE-IT revalidated the concept that low-density lipoprotein cholesterol (LDL-C) levels are a clinically relevant treatment goal. This trial also suggested that further decrease of LDL-C levels (53 vs. 70 mg/dl; 1.4 vs. 1.8 mmol/l) was more beneficial in lowering CV events. This “even lower is even better” evidence for LDL-C levels may influence future guidelines and the use of new drugs. Furthermore, these findings make ezetimibe a more realistic option to treat patients with statin intolerance or those who cannot achieve LDL-C targets with statin monotherapy.     

Combination lipid therapy in type 2 diabetes mellitus

Introduction: A significant drop in cardiovascular risk has been seen in patients with type 2 diabetes treated with statins. However, this cardiovascular risk remains high, compared with nondiabetic individuals. This is partly due to the typical abnormalities of diabetic dyslipidemia – hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) – that are uncontrolled by statins. For this reason, combination lipid therapy may be considered in patients with type 2 diabetes.

Areas covered: This review presents the main reasons for a combination lipid therapy in type 2 diabetes and the effects of several drugs, including fibrates, pioglitazone, niacin and omega 3, on diabetic dyslipidemia and the prevention of cardiovascular events. The real cardiovascular benefit of fibrates in patients with type 2 diabetes is not totally clear, but they may produce a significant benefit in patients with type 2 diabetes and diabetic dyslipidemia (hypertriglyceridemia, low HDL-C). Pioglitazone, which reduces triglycerides and increases HDL-C, has been shown to reduce the risk for major cardiovascular events in type 2 diabetes. Niacin and omega 3 fatty acids have a positive effect on diabetic dyslipidemia, but warrants clinical trials to demonstrate a clear cardiovascular benefit in type 2 diabetes.

Expert opinion: Although combination lipid therapy seems to be useful to control diabetic dyslipidemia, the efficacy of such combined therapies on significantly reducing cardiovascular risk has still to be confirmed by additional clinical trials.     

Role of Colesevelam in Combination Lipid-Lowering Therapy

Hyperlipidemia is associated with an increased risk of cardiovascular events; reducing low-density lipoprotein cholesterol (LDL-C), the primary target for cholesterol-lowering therapy, lowers the risk for such events. Although bile acid sequestrants were the first class of drugs to show a mortality benefit related to LDL-C lowering, statins are now considered first-line pharmacological therapy for reducing LDL-C levels because of their potency and their remarkable record of successful outcomes studies. Nevertheless, a substantial proportion of patients do not achieve LDL-C goals with statin monotherapy. In addition, because of adverse effects (primarily myopathy), some patients may be unwilling to use or unable to tolerate statin therapy at all or may not tolerate a full therapeutic statin dose. Also, statins may increase risk of new-onset diabetes in patients at high risk for diabetes. Thus, there remains a need for other lipid-lowering drugs to be used in combination with or in place of statins. The purpose of this article is to review available data from the literature on the use of colesevelam, a second-generation bile acid sequestrant, in combination with other lipid-lowering agents. Colesevelam has been studied in combination with statins, niacin, fibrates, and ezetimibe (including some three-drug combinations). An additive reduction in LDL-C was seen with all combinations. Other observed effects of colesevelam in combination with other lipid-lowering drugs include reductions in apolipoprotein (apo) B (with statins, fibrates, ezetimibe, statin plus niacin, or statin plus ezetimibe) and high-sensitivity C-reactive protein (with statins), and increases in apo A-I (with statins, ezetimibe, or statins plus niacin). Triglyceride levels remained relatively unchanged when colesevelam was combined with statins, fibrates, ezetimibe, or statin plus ezetimibe, and decreased with the triple combination of colesevelam, statin, and niacin. Colesevelam offset the negative glycemic effects of statins and niacin in subjects with insulin resistance or impaired glucose tolerance. Colesevelam was generally well tolerated when added to other lipid-lowering therapies in clinical trials, with gastrointestinal effects such as constipation being the predominant adverse events. Since colesevelam is not absorbed and works primarily in the intestine, it has a low potential for systemic metabolic drug–drug interactions with other drugs. Colesevelam has been shown to not interact with the lipid-lowering drugs lovastatin and fenofibrate; where interaction may be anticipated, separating dosing times by 4 h reduces the impact of any interaction. Available data confirms that colesevelam has additive cholesterol-lowering effects when used in combination with other lipid-lowering therapies. Furthermore, in some patient populations, the additional glucose-lowering effect of colesevelam may be beneficial in offsetting hyperglycemic effects of other lipid-lowering drugs.     

Perspectives on low-density lipoprotein cholesterol goal achievement

ABSTRACT

Background: Elevated levels of low-density lipoprotein cholesterol (LDL-C) are associated with an increased risk of coronary heart disease (CHD). European and US guidelines now recommend lower LDL-C levels, particularly in high-risk patients. Although LDL-C treatment goals to reduce the risk of CHD are clear, many patients do not reach their LDL-C goals.

Objectives: Examine consensus guideline targets for LDL-C lowering in patients at high or very high cardiovascular risk; examine cholesterol goal achievement in clinical practice; evaluate the effectiveness of ezetimibe/statin and other adjunctive lipid-lowering treatments in achieving LDL-C goals; and consider ongoing controversies and the randomized controlled trials that may help to resolve or better illuminate them.

Methods: An English-language PubMed search was conducted to identify prospective randomized controlled trials, open-label studies, and retrospective and observational studies from 2001 (same year that the executive summary of the National Cholesterol Education Program's Adult Treatment Panel III was published) to present for an analysis of the effects of adjunctive therapies on LDL-C lowering and goal attainment in patients at elevated cardiovascular risk.

Results: Elevated LDL-C is the primary target of lipid-lowering therapy; aggressive lowering is of great benefit to those at high risk. Statins are recommended first-line lipid-lowering agents, with a long, well-regarded history of efficacy and safety. Not all patients, however, can achieve recommended LDL-C goals simply using starting doses of statins. For such patients, more intensive therapy utilizing high-dose statins or combination therapy, including statins combined with other lipid-lowering agents, such as ezetimibe, bile acid resins (BARs), or niacin, is warranted. Potential limitations of the present review include possible publication bias and the focus on pharmacotherapy rather than lifestyle modification and the important objective of multiple risk-factor modification to reduce absolute global cardiovascular risk.

Conclusions: With a well-established link between elevated LDL-C and cardiovascular risk, aggressive LDL-C lowering becomes particularly important. Patients needing intensive LDL-C lowering to achieve goals will often require adjunctive treatments, including ezetimibe, BARs, or niacin along with statins. Given both their high mg: mg potency in lowering LDL-C and favorable tolerability and patient acceptance/adherence profile, ezetimibe/statin combination regimens arguably provide the greatest likelihood for patients to reach new, lower LDL-C targets; however, efficacy and safety data of any adjunctive treatment, along with drug costs and patient adherence to treatment (partly related to complexity of the regimen) all need to be considered when determining the optimal regimen to achieve LDL-C goals in individual patients according to their baseline absolute cardiovascular risk, LDL-C level, and consensus LDL-C targets.     

Statin-fibrate combination therapy for hyperlipidaemia: a review

SUMMARY

Statins and fibrates are well-established treatments for hyperlipidaemias and the prevention of vascular events. However, fibrate?+?statin therapy has been restricted following early reports of rhabdomyolysis that mainly involved gemfibrozil, originally with lovastatin, and recently, with cerivastatin. Despite this limitation, several reports describing combination therapy have been published. This review considers these studies and the relevant indications and contraindications.

Statin?+?fibrate therapy should be considered if monotherapy or adding other drugs (e.g. cholesterol absorption inhibitors, omega-3 fatty acids or nicotinic acid) did not achieve lipid targets or is impractical. Combination therapy should be hospital-based and reserved for high-risk patients with a mixed hyperlipidaemia characterised by low density lipoprotein cholesterol (LDL)?>?2.6?mmol/l (100?mg/dl), high density lipoprotein cholesterol (HDL)?<?1.0?mmol/l (40?mg/dl) and/or triglycerides?>?5.6?mmol/l (500?mg/dl). These three ‘goals’ are individually mentioned in guidelines. Patients should have normal renal, liver and thyroid function tests and should not be receiving therapy with cyclosporine, protease inhibitors or drugs metabolised through cytochrome P450 (especially 3A4). Combination therapy is probably best conducted using drugs with short plasma half-lives; fibrates should be prescribed in the morning and statins at night to minimise peak dose interactions. Both drug classes should be progressively titrated from low doses. Regular (3-monthly) monitoring of liver function and creatine kinase is required.

In conclusion, fibrate?+?statin therapy remains an option in high-risk patients. However, long-term studies involving safety monitoring and vascular endpoints are required to demonstrate the efficacy of this regimen.     

Retrospective study on antihyperlipidemic efficacy and safety of simvastatin,ezetimibe and their combination in Korean adults

Antihyperlipidemic agents such as 3-hydroxymethyglutaryl-coenzyme A reductase inhibitors and cholesterol transporter inhibitors are used in coronary heart disease. However, controversy remains over the pharmacologic effects and safety of these drugs, especially when used in combination therapies. This retrospective study evaluated the therapeutic effect and safety of simvastatin 20 mg and ezetimibe 10 mg combination therapy compared to simvastatin 20 mg or ezetimibe 10 mg monotherapy in Korean patients according to gender, age, baseline low-density lipoprotein cholesterol, and cardiovascular risk factors. We observed significant differences among patient subgroups. Simvastatin and ezetimibe monotherapies and combination therapy reduced low-density lipoprotein cholesterol levels by 27.6%, 10.1%, and 36.8% (p < 0.001) and total cholesterol levels by 17.5%, 9.2%, and 25.3% (p < 0.001), respectively. Both monotherapy and combination therapy groups had similar incidences of all types of adverse events. However, one case of rhabdomyolysis was observed in the combination therapy group. These results suggest that, compared to monotherapy, combination therapy has an additive effect that is not influenced by risk factors. Despite the low incidence of adverse events, caution is required when using these drugs, especially in the context of musculoskeletal side effects.     

PCSK9 inhibitors for treating hypercholesterolemia

ABSTRACT

Introduction: Scientific evidence on subjects treated with statin or other lipid-lowering treatments has established that treatments aiming to lower low-density lipoprotein cholesterol (LDL-C) can reduce atherosclerosis. PCSK9 inhibitors (PCSK9-i), thanks to their efficacy in reducing LDL-C constitute a further step in the treatment of dyslipidemia and cardiovascular (CV) diseases.

Areas covered: The purpose of this narrative review is to summarize the current knowledge of PCSK9-i, with particular regard to pharmacodynamic, pharmacokinetic, and clinical data on evolocumab and alirocumab.

Expert opinion: PCSK9-I are effective in reducing atherosclerotic events through their significant LDL-C-lowering action similarly to statins. Furthermore, these drugs can be considered safe and well-tolerated. However, some controversies remain with regard to their efficacy in reducing mortality and the paucity of data on both pleiotropic effects and long-term safety of these drugs. However, future studies will focus on understanding the effects of very low cholesterol levels on health. At present, we know that the genetic model of PCSK9 deficiency is characterized by very low LDL-C levels without particular health problems. Yet, we do not know the effect of prolonged PCSK9 inhibition induced by antibody action during the lifetime of normal subjects.     

The use of ezetimibe in achieving low density lipoprotein lowering goals in clinical practice: position statement of a United Kingdom consensus panel

ABSTRACT

There is no doubt that lowering serum cholesterol levels reduces the risk of major coronary events. This evidence has led treatment guidelines to set progressively lower targets for low density lipoprotein cholesterol (LDL-C). However, despite widespread use of statins, substantial numbers of patients do not achieve the LDL-C goals. Using higher doses of statins in an attempt to achieve these targets may increase the risk of serious adverse effects. Furthermore, the use of combination therapy with agents such as bile acid sequestrants, niacin and fibrates has been limited by increased potential for side effects, drug interactions and poor compliance.

Ezetimibe, a selective cholesterol transport inhibitor, reduces the intestinal uptake of cholesterol without affecting absorption of triglycerides or fatsoluble vitamins. In clinical studies, ezetimibe 10?mg, in combination with statins or as monotherapy, was well tolerated and reduced LDL-C by 34–53% and 17–18%, respectively.

The available evidence for ezetimibe is reviewed. The role of ezetimibe in increasing the proportion of patients attaining LDL-C treatment goals is discussed.     

Impact of SLCO1B1 (OATP1B1) and ABCG2 (BCRP) genetic polymorphisms and inhibition on LDL-C lowering and myopathy of statins

Statins are the preferred class of drugs for treating patients with atherosclerosis and related coronary heart disease. Treatment with statins leads to significant low-density lipoprotein cholesterol (LDL-C) lowering, resulting in reductions in major coronary and vascular events. Statins are generally well tolerated and safe; however, their use is complicated by infrequent, but often serious, muscular adverse events. For many statins, both efficacy and risk of adverse muscle events can be influenced by membrane transporters, which are important determinants of statin disposition. Genetic polymorphisms and drug-drug interactions (DDIs) involving organic anion-transporting polypeptide 1B1 and breast cancer resistance protein have shown the capacity to reduce the activity of these transporters, resulting in changes in LDL-C lowering by statins, as well as changes in the frequency of adverse muscle events associated with their use. This review presents evidence for how reduced transporter activity impacts the safety and pharmacology of statins. It expands on the scope of other recent statin reviews by providing recommendations on in vitro evaluation of statin interaction potential, discussing how reduced transporter activity impacts statin management during drug development, and proposing ideas on how to evaluate the impact of DDI on statin efficacy during clinical trials. Furthermore, the potential clinical consequences of perturbing statin efficacy via DDI are discussed.