Comparative efficacy and safety of pravastatin, nicotinic acid and the two combined in patients with hypercholesterolemia

Pravastatin for lowering lipids

BACKGROUND

A detailed summary and meta-analysis of the dose-related effect of pravastatin on lipids is not available.

OBJECTIVES

Primary objective To assess the pharmacology of pravastatin by characterizing the dose-related effect and variability of the effect of pravastatin on the surrogate marker: low-density lipoprotein (LDL cholesterol). The effect of pravastatin on morbidity and mortality is not the objective of this systematic review. Secondary objectives • To assess the dose-related effect and variability of effect of pravastatin on the following surrogate markers: total cholesterol; high-density lipoprotein (HDL cholesterol); and triglycerides. • To assess the effect of pravastatin on withdrawals due to adverse effects.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to September 2021: CENTRAL (2021, Issue 8), Ovid MEDLINE, Ovid Embase, Bireme LILACS, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

Randomized placebo-controlled trials evaluating the dose response of different fixed doses of pravastatin on blood lipids over a duration of three to 12 weeks in participants of any age with and without evidence of cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included, and extracted data. We entered lipid data from placebo-controlled trials into Review Manager 5 as continuous data and withdrawal due to adverse effects (WDAEs) data as dichotomous data. We searched for WDAEs information from all trials. We assessed all trials using Cochrane's risk of bias tool under the categories of sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases.

MAIN RESULTS

Sixty-four RCTs evaluated the dose-related efficacy of pravastatin in 9771 participants. The participants were of any age, with and without evidence of cardiovascular disease, and pravastatin effects were studied within a treatment period of three to 12 weeks. Log dose-response data over the doses of 5 mg to 160 mg revealed strong linear dose-related effects on blood total cholesterol and LDL cholesterol, and a weak linear dose-related effect on blood triglycerides. There was no dose-related effect of pravastatin on blood HDL cholesterol. Pravastatin 10 mg/day to 80 mg/day reduced LDL cholesterol by 21.7% to 31.9%, total cholesterol by 16.1% to 23.3%,and triglycerides by 5.8% to 20.0%. The certainty of evidence for these effects was judged to be moderate to high. For every two-fold dose increase there was a 3.4% (95% confidence interval (CI) 2.2 to 4.6) decrease in blood LDL cholesterol. This represented a dose-response slope that was less than the other studied statins: atorvastatin, rosuvastatin, fluvastatin, pitavastatin and cerivastatin. From other systematic reviews we conducted on statins for its effect to reduce LDL cholesterol, pravastatin is similar to fluvastatin, but has a decreased effect compared to atorvastatin, rosuvastatin, pitavastatin and cerivastatin. The effect of pravastatin compared to placebo on WADES has a risk ratio (RR) of 0.81 (95% CI 0.63 to 1.03). The certainty of evidence was judged to be very low.

AUTHORS' CONCLUSIONS

Pravastatin lowers blood total cholesterol, LDL cholesterol and triglyceride in a dose-dependent linear fashion. This review did not provide a good estimate of the incidence of harms associated with pravastatin because of the lack of reporting of adverse effects in 48.4% of the randomized placebo-controlled trials.

Nicotinic acid promotes sleep through prostaglandin synthesis in mice

Nicotinic acid has been used for decades for its antiatherogenic properties in humans. Its actions on lipid metabolism intersect with multiple sleep regulatory mechanisms, but its effects on sleep have never been documented. For the first time, we investigated the effects of acute systemic administration of nicotinic acid on sleep in mice. Intraperitoneal and oral gavage administration of nicotinic acid elicited robust increases in non-rapid-eye movement sleep (NREMS) and decreases in body temperature, energy expenditure and food intake. Preventing hypothermia did not affect its sleep-inducing actions suggesting that altered sleep is not secondary to decreased body temperature. Systemic administration of nicotinamide, a conversion product of nicotinic acid, did not affect sleep amounts and body temperature, indicating that it is not nicotinamide that underlies these actions. Systemic administration of monomethyl fumarate, another agonist of the nicotinic acid receptor GPR109A, fully recapitulated the somnogenic and thermoregulatory effects of nicotinic acid suggesting that they are mediated by the GPR109A receptor. The cyclooxygenase inhibitor indomethacin completely abolished the effects of nicotinic acid indicating that prostaglandins play a key role in mediating the sleep and thermoregulatory responses of nicotinic acid.

P465L-PPARγ mutation confers partial resistance to the hypolipidaemic action of fibrates

AIMS

Familial partial lipodystrophic syndrome 3 (FPLD3) is associated with mutations in the transcription factor PPARγ. One of these mutations, the P467L, confers a dominant negative effect. We and others have previously investigated the pathophysiology associated with this mutation using a humanized mouse model that recapitulates most of the clinical symptoms observed in patients who have been phenotyped under different experimental conditions. One of the key clinical manifestations observed, both in humans and mouse models, is the ectopic accumulation of fat in the liver. With this study we aim to dissect the molecular mechanisms that contribute to the excessive accumulation of lipids in the liver and characterize the negative effect of this PPARγ mutation on the activity of PPARα in vivo when activated by fibrates.

MATERIAL AND METHODS

P465L-PPAR mutant and wild-type mice were divided into 8 experimental groups, 4 different conditions per genotype. Briefly, mice were fed a chow diet or a high-fat diet (HFD 45% Kcal from fat) for a period of 28 days and treated with WY14643 or vehicle for five days before culling. At the end of the experiment, tissues and plasma were collected. We performed extensive gene expression, fatty acid composition and histological analysis in the livers. The serum collected was used to measure several metabolites and to perform basic lipoprotein profile.

RESULTS

P465L mice showed increased levels of insulin and free fatty acids (FFA) as well as increased liver steatosis. They also exhibit decreased levels of very low density lipoproteins (VLDL) when fed an HFD. We also provide evidence of impaired expression of a number of well-established PPARα target genes in the P465L mutant livers.

CONCLUSION

Our data demonstrate that P465L confers partial resistance to the hypolipidemic action of fibrates. These results show that the fatty liver phenotype observed in P465L mutant mice is not only the consequence of dysfunctional adipose tissue, but also involves defective liver metabolism. All in all, the deleterious effects of P465L-PPARγ mutation may be magnified by their collateral negative effect on PPARα function.

Niacin inhibits fat accumulation, oxidative stress, and inflammatory cytokine IL-8 in cultured hepatocytes: Impact on non-alcoholic fatty liver disease

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is a common disorder characterized by excessive hepatic fat accumulation, production of reactive oxygen species (ROS), inflammation and potentially resulting in non-alcoholic steatohepatitis (NASH), cirrhosis and end-stage liver disease. Recently, we have shown that niacin significantly prevented hepatic steatosis and regressed pre-existing steatosis in high-fat fed rat model of NAFLD. To gain further insight into the cellular mechanisms, this study investigated the effect of niacin on human hepatocyte fat accumulation, ROS production, and inflammatory mediator IL-8 secretion.

MATERIALS AND METHODS

Human hepatoblastoma cell line HepG2 or human primary hepatocytes were first stimulated with palmitic acid followed by treatment with niacin or control for 24 h.

RESULTS

The data indicated that niacin (at 0.25 and 0.5 mmol/L doses) significantly inhibited palmitic acid-induced fat accumulation in human hepatocytes by 45-62%. This effect was associated with inhibition of diacylglycerol acyltransferase 2 (DGAT2) mRNA expression without affecting the mRNA expression of fatty acid synthase (FAS) and carnitine palmitoyltransferase 1 (CPT1). Niacin attenuated hepatocyte ROS production and it also inhibited NADPH oxidase activity. Niacin reduced palmitic acid-induced IL-8 levels.

CONCLUSIONS

These findings suggest that niacin, through inhibiting hepatocyte DGAT2 and NADPH oxidase activity, attenuates hepatic fat accumulation and ROS production respectively. Decreased ROS production, at least in part, may have contributed to the inhibition of pro-inflammatory IL-8 levels. These mechanistic studies may be useful for the clinical development of niacin and niacin-related compounds for the treatment of NAFLD/NASH and its complications.

Important considerations for treatment with dietary supplement versus prescription niacin products

Niacin is a water-soluble B vitamin (B3) known to have favorable effects on multiple lipid parameters, including raising high-density lipoprotein cholesterol (HDL-C) levels and lowering triglycerides (TGs), lipoprotein(a), and low-density lipoprotein cholesterol (LDL-C). Although LDL-C remains the primary target of lipid-altering therapy, current guidelines emphasize HDL-C and other modifiable lipid factors as key secondary targets. Thus, niacin is considered an important therapeutic option to help reduce the risk of cardiovascular disease in patients with mixed dyslipidemia who, in addition to high LDL-C, have elevated TGs and low HDL-C. Although available prescription niacin products, including immediate-release niacin (IR; Niacor) and an extended-release niacin formulation (Niaspan), have demonstrated safety and efficacy in randomized clinical trials, confusion remains among health care providers and their patients regarding the various commercially available nonprescription dietary supplement niacin products. These dietary supplements, which include IR, sustained-release (SR), and "no-flush" or "flush-free" niacin products, are not subject to the same stringent US Food and Drug Administration regulations as prescription drugs. In fact, both the American Heart Association and the American Pharmacists Association recommend against the use of dietary supplement niacin as a substitute for prescription niacin. Although some dietary supplement IR and SR niacin products have demonstrated a lipid response in clinical trials, products labeled as "no-flush" or "flush-free" that are intended to avoid the common niacin-associated adverse effect of flushing generally contain minimal or no free, pharmacologically active niacin and therefore lack beneficial lipid-modifying effects. To clarify important differences between available prescription and dietary supplement niacin products, this article contrasts current regulatory standards for dietary supplements and prescription drugs and provides an overview of available clinical data from key trials of niacin.

A "hot" topic in dyslipidemia management--"how to beat a flush": optimizing niacin tolerability to promote long-term treatment adherence and coronary disease prevention

Niacin is the most effective lipid-modifying agent for raising high-density lipoprotein cholesterol levels, but it also causes cutaneous vasodilation with flushing. To determine the frequency of flushing in clinical trials, as well as to delineate counseling and treatment approaches to prevent or manage flushing, a MEDLINE search was conducted of English-language literature from January 1, 1985, through April 7, 2009. This search used the title keywords niacin or nicotinic acid crossed with the Medical Subject Headings adverse effects and human. Niacin flushing is a receptor-mediated, mainly prostaglandin D(2)-driven phenomenon, the frequency, onset, and duration of which are largely determined by the distinct pharmacological and metabolic profiles of different niacin formulations. Subjective assessments include ratings of redness, warmth, itching, and tingling. In clinical trials, most (>60%) niacin users experienced mild or moderate flushing, which tended to decrease in frequency and severity with continued niacin treatment, even with advancing doses. Approximately 5% to 20% of patients discontinued treatment because of flushing. Flushing may be minimized by taking niacin with meals (or at bedtime with a low-fat snack), avoiding exacerbating factors (alcohol or hot beverages), and taking 325 mg of aspirin 30 minutes before niacin dosing. The current review advocates an initially slow niacin dose escalation from 0.5 to 1.0 g/d during 8 weeks and then from 1.0 to 2.0 g in a single titration step (if tolerated). Through effective counseling, treatment prophylaxis with aspirin, and careful dose escalation, adherence to niacin treatment can be improved significantly. Wider implementation of these measures should enable higher proportions of patients to reach sufficient niacin doses over time to prevent cardiovascular events.

The Role of Statin Drugs in the Management of the Peripheral Vascular Patient

The impact of statin therapy on established vascular conditions and recurrent disease is most relevant for long-term care. Patients receiving statin therapy have been shown to experience less recurrent stenosis following carotid endarterectomy and stent angioplasty, reduced cardiac events following cardiac and noncardiac vascular surgery, and reduction in aneurysm development. In patients with peripheral arterial disease, claudication distance is increased, as well as patency rates following infrainguinal arterial bypass grafting. Of note, statins drugs may also prove beneficial in the prevention of certain cancers, Alzheimer's disease, and osteoporosis (all diseases frequently seen concurrently in the patient with peripheral arterial disease). As such, it is becoming all the more necessary that vascular surgeons remain informed about clinical research initiatives related to statin use and lipid management in general. The following is a review of lipid metabolism as it applies to statins as well as a review of the beneficial effects of statins.

Rosuvastatin Alone or With Extended‐Release Niacin: A New Therapeutic Option for Patients With Combined Hyperlipidemia

Combination therapy with a statin and niacin may provide optimal therapy for patients with combined hyperlipidemia and low levels of high-density lipoprotein (HDL) cholesterol. The authors assessed the efficacy and safety of rosuvastatin monotherapy, extended-release (ER) niacin monotherapy, or rosuvastatin and ER niacin combined therapy in patients with atherogenic dyslipidemia. In a 24-week, open-label, multicenter trial, men and women aged > or =18 years with fasting levels of total cholesterol > or =200 mg/dL, HDL cholesterol > or =45 mg/dL, triglycerides 200-800 mg/dL, and apolipoprotein B > or =110 mg/dL were randomly assigned to one of four treatment groups: rosuvastatin 10-40 mg, ER niacin 0.5-2 g, rosuvastatin 40 mg plus ER niacin 0.5-1 g, or rosuvastatin 10 mg plus ER niacin 0.5-2 g. Daily doses of rosuvastatin 40 mg monotherapy reduced low-density lipoprotein (LDL) cholesterol and non-HDL cholesterol levels significantly more than did either ER niacin 2 g monotherapy or rosuvastatin 10 mg combined with ER niacin 2 g. Addition of ER niacin 1 g to rosuvastatin 40 mg did not further reduce total or non-HDL cholesterol. Triglyceride reductions were similar among the four treatment groups. ER niacin mono- and combined therapy produced significantly greater rises in HDL cholesterol and apolipoprotein A-1 than did rosuvastatin monotherapy. Rosuvastatin monotherapy was better tolerated than ER niacin taken either alone or with rosuvastatin. In this study, rosuvastatin very effectively improved the three major lipoprotein-lipid abnormalities of combined hyperlipidemia.

Suppression of Niacin-induced Vasodilation with an Antagonist to Prostaglandin D2 Receptor Subtype 1

Niacin (nicotinic acid) reduces cardiovascular events in patients with dyslipidemia. However, symptoms associated with niacin-induced vasodilation (e.g., flushing) have limited its use. Laropiprant is a selective antagonist of the prostaglandin D(2) receptor subtype 1 (DP1), which may mediate niacin-induced vasodilation. The aim of this proof-of-concept study was to evaluate the effects of laropiprant (vs placebo) on niacin-induced cutaneous vasodilation. Coadministration of laropiprant 30, 100, and 300 mg with extended-release (ER) niacin significantly lowered flushing symptom scores (by approximately 50% or more) and also significantly reduced malar skin blood flow measured by laser Doppler perfusion imaging. Laropiprant was effective after multiple doses in reducing symptoms of flushing and attenuating the increased malar skin blood flow induced by ER niacin. In conclusion, the DP1 receptor antagonist laropiprant was effective in suppressing both subjective and objective manifestations of niacin-induced vasodilation.

Evaluation of efficacy and safety of fixed dose lovastatin and niacin(ER) combination in asian Indian dyslipidemic patients: a multicentric study

Asian Indian dyslipidemia is characterized by: borderline high low-density lipoprotein (LDL) cholesterol and apolipoprotein (apo) B; high triglycerides, low high-density lipoprotein (HDL) cholesterol and apoA1; and high lipoprotein(a) (lp[a]). We performed a controlled multicentric trial in India to evaluate the efficacy and safety of a fixed dose combination of lovastatin and niacin extended release (niacin^ER) formulation in patients with moderate to severe dyslipidemia. Consecutive subjects that satisfied the selection criteria, agreed to an informed consent, and with no baseline presence of liver/renal disease or heart failure were enrolled in the study. After a 4-week run-in period there were 142 patients with LDL levels ≥130 mg/dL. Eleven patients were excluded because of uncontrolled hyperglycemia and 131 patients were recruited. After baseline evaluation of clinical and biochemical parameters all subjects were administered lovastatin (20 mg) and niacin^ER (500 mg) combination once daily. Dose escalation was done on basis of lipid parameters at 8 weeks and in 11 patients increased to lovastatin (20 mg) and niacin^ER (1000 mg). An intention-to-treat analysis was performed and data was analyzed using nonparametric Wilcoxon signed rank test. Thirteen patients (10%) were lost to follow-up and 4 (3%) withdrew because of dermatological adverse effects: flushing, pruritus, and rash. The mean values of various lipid parameters (mg/dL) at baseline, and at weeks 4, 12, and 24 respectively were: total cholesterol 233.9 ± 27, 206.3 ± 27, 189.8 ± 31, and 174.9 ± 27 mg/dL; LDL cholesterol 153.4 ± 22, 127.3 ± 21, 109.2 ± 27, and 95.1 ± 23 mg/dL; triglycerides 171.1 ± 72, 159.5 ± 75, 149.2 ± 45, and 135.2 ± 40 mg/dL; HDL cholesterol 45.6 ± 7, 48.9 ± 7, 51.6 ± 9, and 53.9 ± 10 mg/dL; lp(a) 48.5 ± 26, 40.1 ± 21, 35.4 ± 21, and 26.9 ± 19 mg/dL; and apoA1/apoB ratio 0.96 ± 0.7, 1.04 ± 0.4, 1.17 ± 0.5, and 1.45 ± 0.5 (p < 0.01). The percentage of decline in various lipids at 4, 12, and 24 weeks was: total cholesterol 11.8%, 18.8%, and 25.2%; LDL cholesterol 17.0%, 28.8%, and 38.0%; triglyceride 6.8%, 12.8%, and 21.0%; lp(a) 17.5%, 26.9%, and 44.5% respectively (p < 0.01). HDL cholesterol and apoA1/apoB increased by 7.2%, 13.1%, and 18.2%; and 7.9%, 21.9%, and 51.6% respectively (p < 0.01). Target LDL levels (<100 mg/dL in subjects with manifest coronary heart disease or diabetes; <130 mg/dL in subjects with >2 risk factors) were achieved in 92 (80.7%) patients. No significant changes were observed in systolic or diastolic blood pressure, blood creatinine, transaminases, or creatine kinase. A fixed dose combination of lovastatin and niacin^ER significantly improved cholesterol lipoprotein lipids as well as lp(a) and apoA1/apoB levels in Asian Indian dyslipidemic patients. Satisfactory safety and tolerability profile in this population was also demonstrated.

Safety of lovastatin/extended release niacin compared with lovastatin alone, atorvastatin alone, pravastatin alone, and simvastatin alone (from the United States Food and Drug Administration adverse event reporting system)

Recent national guidelines support combination drug therapy targeting multiple lipid abnormalities. Current drug labeling warns of an increased risk of adverse events with statin and niacin combinations. These recommendations have been based solely on case reports. We compared the rates of adverse event reports (AERs) received by the United States Food and Drug Administration (1999 to March 2005) associated with the combination of lovastatin/niacin-extended release (ER) with those of lovastatin or niacin-ER alone, and other commonly used statins. The following AERs were considered: events that were fatal, life-threatening, or resulted in hospitalization (serious AERs), hepatotoxicity (liver AERs), and rhabdomyolysis (rhabdomyolysis AERs). We also calculated the prevalence of concomitant niacin-ER therapy in statin-associated AERs. The rate of serious AERs associated with the combination lovastatin/niacin-ER was similar to that of lovastatin or niacin-ER alone, and significantly less than that of atorvastatin or simvastatin. Likewise, the rates of liver and rhabdomyolysis AERs associated with lovastatin/niacin-ER were similar to those of the other statins or niacin-ER alone and lower than those of simvastatin-associated rhabdomyolysis reports (p <0.01). Concomitant niacin-ER use in statin-associated AERs was rare (<or=1%). In conclusion, these findings do not support a clinically significant adverse drug interaction between niacin-ER and statins and should encourage the safe use of this combination in appropriate high-risk patients, as recommended by the national guidelines.

Systematic review and meta-analysis of clinically relevant adverse events from HMG CoA reductase inhibitor trials worldwide from 1982 to present

PURPOSE

Our objective was to determine the association of clinically relevant adverse events from a systematic review and meta-analysis of statin randomized controlled trials (RCT).

METHODS

We performed the meta-analysis in the manner of a Cochrane Collaboration systematic review. Outcomes were discontinuances of therapy or muscle-related symptoms due to adverse events. We searched for articles from 1982 through June 2006 in MEDLINE and other databases. The main inclusion criteria were double blind, placebo controlled RCTs with a monotherapy intervention of any marketed statin and active surveillance of adverse events. We excluded studies of drug interactions, organ transplants, or exercise, or those not meeting all of the study quality criteria. The primary analysis was a statin formulation stratified fixed-effect model using Peto odds-ratios (POR). Secondary analyses explored the stability of the primary results.

RESULTS

Over 86,000 study participants from 119 studies were included. Available statins were associated with a lower POR of discontinuance (overall: 0.88 [0.84, 0.93], largest effect with pravastatin: 0.79 [0.74, 0.84]), an elevated POR of rhabdomyolysis (1.59 [0.54, 4.70]) and myositis (2.56 [1.12, 5.85]), and null odds of myalgia (1.09 [0.97, 1.23]). Cerivastatin by comparison demonstrated larger PORs for discontinuances and muscle-related adverse events. Secondary analyses demonstrated the stability of the results.

CONCLUSIONS

Overall, discontinuation of statin therapy due to adverse events was no worse than placebo. The risks of muscle-related adverse events were in general agreement with the known risks of statins.

Clinical evidence for use of acetyl salicylic acid in control of flushing related to nicotinic acid treatment

Nicotinic acid (NA) is highly effective and widely used in the management of dyslipidaemia. For many patients, the side effect of flushing of the face and upper body leads to discontinuation. Flushing with NA is mediated by prostaglandins, and as acetyl salicylic acid (ASA, 'aspirin') is a highly effective inhibitor of prostaglandin synthesis, there is a rationale for its use to prevent or reduce the severity of NA-related flushing. This literature survey identified four studies specifically exploring the utility of ASA in preventing NA-related flushing in healthy volunteers. Twenty-three NA studies, where ASA was mandatory or optional within the protocol, and four studies, where background ASA therapy was reported in most participants, were also identified. Although the incidence of flushing in studies using ASA was often high, discontinuation rates due to flushing were low (mean 7.7%). This figure compares favourably with discontinuation rates with NA commonly reported in the literature (up to approximately 40%). There is good supportive evidence for the use of ASA in reducing the severity of NA-related flushing.

Efficacy and safety of high-density lipoprotein cholesterol-increasing compounds: a meta-analysis of randomized controlled trials

OBJECTIVES

The aim of this research was to estimate the efficacy and safety of current high-density lipoprotein cholesterol (HDL-C)-increasing drugs.

BACKGROUND

Epidemiologic evidence has shown that HDL-C is inversely related to coronary heart disease (CHD) risk. However, the evidence for reducing CHD risk by raising HDL-C is thin, predominantly due to the paucity of effective and safe HDL-increasing drugs.

METHODS

Randomized controlled trials with fibrates and niacin, published between 1966 through February 2004 (MEDLINE), were retrieved. Information on treatment, baseline characteristics, serum lipids, end points, and side-effects were independently abstracted by two authors using a standardized protocol.

RESULTS

Data from 53 trials (16,802 subjects) using fibrates and 30 trials (4,749 subjects) using niacin were included. Random-effects model showed 11% versus 10% reduction in total cholesterol, 36% versus 20% reduction in triglycerides, 8% versus 14% reduction in low-density lipoprotein cholesterol, and 10% versus 16% increase in HDL-C for fibrates and niacin, respectively. Apart from flushes in the niacin group, both fibrates and niacin were shown to be well-tolerated and safe. Fibrates reduced the risk for major coronary events by 25% (95% confidence interval 10% to 38%), whereas current available data for niacin indicate a 27% reduction.

CONCLUSIONS

Fibrates reduce major coronary events and increase HDL-C levels without significant toxicity. Niacin has a more potent effect on HDL-C levels, whereas data on cardiovascular event rate reduction are limited. Future studies need to evaluate whether additional HDL increase by fibrates or particularly newer niacin formulations on top of statin therapy translates into further event reduction in high-risk subjects, without significant toxicity.

Clinical Update on the Use of Niacin for the Treatment of Dyslipidemia

PURPOSE

To provide nurse practitioners (NPs) with clinical and practical information about the use of niacin in the treatment of dyslipidemia.

DATA SOURCES

Research-based and review articles in the medical literature and National Cholesterol Education Program guidelines.

CONCLUSIONS

Niacin provides beneficial effects on all major lipid fractions, particularly high-density lipoprotein cholesterol and triglycerides. Niacin also reduces low-density lipoprotein (LDL) cholesterol; lipoprotein (a); and the number of highly atherogenic small, dense LDL particles. Niacin promotes angiographic regression when used in combination with other drugs that lower LDL cholesterol and can reduce cardiovascular risk in patients with coronary heart disease. Several niacin formulations are available, but the safety (i.e., from hepatotoxicity) and tolerability (i.e., severity of flushing) of these niacin formulations may differ.

IMPLICATIONS FOR PRACTICE

Niacin therapy is appropriate for many types of lipid abnormalities, including complex dyslipidemias. NPs can take several steps to minimize potential side effects of niacin therapy and to ensure that patients adhere to this important intervention.

Management of atherogenic dyslipidemia of the metabolic syndrome: evolving rationale for combined drug therapy

Atherogenic dyslipidemia is prevalent in various conditions associated with central obesity, hypertension, hyperurecemia, and impaired beta-cell function (ie, the metabolic syndrome). Because of clinical trial evidence, most high-risk patients with atherogenic dyslipidemia require statin therapy. Coadministration of drugs targeted to reduction of low-density lipoprotein precursors, however,is likely to improve the metabolic profile of all non-high-density lipoproteins and produce a significant rise in high-density lipoprotein cholesterol. Large-scale clinical trials with combined drug therapy that show coronary heart disease (CHD) risk reduction or improvement in CHD are needed. It is also possible that new drugs are needed to target fatty acid metabolism and inflammation. As understanding of the metabolic origins of atherogenic dyslipidemia increases, it is possible that new targets of therapy will be identified and that new drug combinations will prove to be even more efficacious than those currently available for treatment of this condition.

The triglyceride-high-density lipoprotein axis: an important target of therapy?

Coronary heart disease is the single largest cause of morbidity and mortality in the United States. The link between elevated low-density lipoprotein cholesterol (LDL-C) levels and coronary heart disease (CHD) has been clearly established. However, triglycerides (TG) are increasingly believed to be independently associated with CHD, while high-density lipoprotein cholesterol (HDL-C) is inversely associated with CHD risk. High TG and low HDL often occur together, often with normal levels of LDL-C, and can be described as abnormalities of the TG-HDL axis. This lipid abnormality is a fundamental characteristic of patients with the metabolic syndrome, a condition strongly associated with the development of both type 2 diabetes and CHD. Patients with high TG and low HDL-C should be aggressively treated with therapeutic lifestyle changes. For high-risk patients, lipid-modifying therapy that specifically addresses the TG-HDL axis should also be considered. Current pharmacologic treatment options for such patients include statins, fibrates, niacin, fish oils, and combinations thereof. Several new pharmacologic approaches to treating the TG-HDL axis are currently being investigated. More clinical trial data is needed to test the hypothesis that pharmacologic therapy targeting the TG-HDL axis reduces atherosclerosis and cardiovascular events.

Current overview of statin-induced myopathy

Statins are an efficacious and well-tolerated class of lipid-altering agents that have been shown to reduce the risk of initial and recurrent cardiovascular events. However, cerivastatin was withdrawn from the world market because of its potential for severe myotoxic effects. Since the benefits of statin treatment outweigh the small risk of adverse events, statins remain the first-line therapy for lipid lowering and preventing atherosclerotic cardiovascular diseases. The risk of myopathy may be minimized with the appropriate choice of agent and by identifying patients at risk of myotoxic effects. Elderly or female patients, or those with concomitant medications or impaired metabolic processes, may be at increased risk and should be monitored closely. The risk of myopathy may also be inferred from the pharmacologic and pharmacokinetic properties of the statin used. Since myotoxic events are more frequent at higher doses, statins that are effective in reducing cholesterol levels and helping patients to reach target levels at start doses may be useful. The lipophilicity of a statin and its potential for drug-drug interactions may also help to determine the likelihood of muscular effects. Drug-drug interactions may be avoided by selecting a statin that does not share the same metabolic pathway.

Treating dyslipidemic patients with lipid-modifying and combination therapies

Updated guidelines from the National Cholesterol Education Program give greater emphasis to lipoproteins other than low-density lipoprotein cholesterol (LDL) than previous guidelines. Although statins remain first-line therapy for most patients to lower LDL, combination therapy is the next logical step in achieving goals in patients with mixed dyslipidemia or elevated LDL despite statin therapy. As the prevalence of diabetes, metabolic syndrome, and atherogenic dyslipidemia rises, the importance of treating the total lipid profile becomes even more crucial. Niacin, fibrates, and bile acid sequestrants are effective in combination with statins in lowering LDL, triglycerides, and total cholesterol levels and increasing high-density lipoprotein cholesterol (HDL). Although combination therapies may increase the risk of myopathy, both fibrate-statin and niacin-statin combinations are considered safe. In addition, niacin-statin therapy reduces atherosclerotic progression and coronary events. New pharmacologic formulations exist that will further affect treatment: a single-tablet combination of lovastatin and extended-release niacin is available, as is ezetimibe, a cholesterol-absorption inhibitor. In all, both HDL and triglyceride levels correlate with cardiovascular risk and should be considered secondary targets of therapy. Combination therapy can be safe and effective and can be constructed to affect all lipoprotein parameters.

Niacin-ER and lovastatin treatment of hypercholesterolemia and mixed dyslipidemia

OBJECTIVE

To review the currently available information on the once-daily combination of niacin extended-release (ER)/lovastatin in the treatment of patients with hypercholesterolemia and mixed dyslipidemia at high risk for cardiovascular events.

DATA SOURCES

MEDLINE (1966-July 2002) was searched for primary and review articles. Data from the manufacturer were also included.

STUDY SELECTION/DATA EXTRACTION

All articles and product labeling deemed relevant to the combination of niacin and statins (i.e., lovastatin) were included for review. English-language studies selected for inclusion were limited to those with human subjects.

DATA SYNTHESIS

The Food and Drug Administration approved a new fixed-dose combination of niacin-ER/lovastatin, which is administered once daily. The efficacy and safety of the combined agent have been proven to be similar to either component used alone or in combination for management of hyperlipidemia and mixed dyslipidemia.

CONCLUSIONS

Elevated low-density lipoprotein cholesterol (LDL-C) is independently associated with a higher risk for cardiovascular events. Lowering of elevated LDL-C concentrations with statin monotherapy may be insufficient in patients at high risk for cardiovascular events. In fact, consideration of elevated triglycerides (TGs) and/or low concentrations of high-density lipoprotein cholesterol (HDL-C) in patients with elevated LDL-C places them at greater risk. The addition of niacin may enhance or improve the lipid profile of those who require a further decrease of TGs and/or increase of HDL-C even after stable statin therapy. Niacin-ER offers efficacy similar to that of immediate-release niacin, but minimal myopathy and hepatotoxicity (compared with sustained-release niacin). Although no clinical outcomes are available, current evidence shows that the combination product offers adequate lowering of LDL-C and TGs and increasing HDL-C. The data suggest that therapy with the niacin-ER and lovastatin combination product is safe and does not increase the incidence of adverse effects.

A novel mechanism for the beneficial vascular effects of high-density lipoprotein cholesterol: enhanced vasorelaxation and increased endothelial nitric oxide synthase expression

BACKGROUND

Low levels of high-density lipoprotein (HDL) cholesterol increase the risk of coronary artery disease (CAD), and recent clinical studies suggest that interventions in low-HDL patients are beneficial. The purpose of this study was to examine the effect of increased HDL levels on endothelium-dependent vasodilation.

METHODS

We studied patients with CAD with a low-density lipoprotein (LDL) level of <100 mg/dL. Patients with an HDL level of < or =36 mg/dL were treated with niacin (n = 11), and patients with an HDL level of >36 mg/dL were followed as controls (n = 10). Baseline and 3-month follow-up studies of flow-mediated dilation (FMD) and blood lipid levels were obtained.

RESULTS

HDL levels increased from 30.1 +/- 1.2 to 40.5 +/- 1.2 mg/dL in the niacin-treated patients (P <.001) but remained unchanged in the control patients. At baseline, FMD was impaired in both the treated (6.5% +/- 1%) and the control (7.3% +/- 1%) patients compared with 10 healthy subjects (16% +/- 2%, P <.01). After 3 months, FMD improved in the niacin-treated patients (11.8% +/- 1%, P =.001) but remained unchanged in the control patients (6.2% +/- 1%). Exposure of cultured human vascular endothelial cells to HDL in vitro enhanced expression of endothelial nitric oxide synthase (eNOS), as shown by immunoblotting.

CONCLUSIONS

In patients with CAD and well-controlled LDL levels, elevation of HDL with niacin improves endothelial function. HDL increases eNOS protein expression in cultured vascular endothelial cells. Taken together, these observations suggest that HDL-mediated increases in eNOS expression may contribute to the observed enhancement in vasorelaxation and thus support a previously unrecognized mechanism for the beneficial cardiovascular effects of HDL.

Effect of very-low-dose niacin on high-density lipoprotein in patients undergoing long-term statin therapy

BACKGROUND

A low level of high-density lipoprotein (HDLC) is a proven risk factor for coronary artery disease. Niacin raises HDLC levels, but it is infrequently used because of its side effect profile. Niacin's side effects are dose related. This study tests the hypothesis that very low-dose niacin, in conjunction with long-term statin therapy, will improve the lipid profile by significantly raising the level of HDLC, with fewer side effects than traditional doses of niacin.

METHODS

Fifty patients undergoing stable statin therapy for 3 months were blindly randomized to receive either placebo or niacin 50 mg administered by mouth 2 times daily for 3 months. Patients with diabetes and active smokers were excluded. Each patient completed a questionnaire regarding current medical problems, medications, and lifestyle before and after the therapy. Patients were questioned about any possible side effects that occurred during the medication trial. The primary end points were change in HDLC level and patient-reported side effects.

RESULTS

Thirty-nine patients completed the study. Very low-dose niacin added to statin therapy increased the mean HDLC, 2.1 mg/dL in niacin group (standard error of the mean, 0.767) versus -0.56 mg/dL for placebo group (standard error of the mean-.816, P =.0246 by analysis of variance). Five patients receiving niacin, versus 2 patients receiving placebo, had episodes of flushing. No major side effects were noted. No patients stopped the study medication as a result of side effects.

CONCLUSIONS

The addition of very low-dose niacin to statin therapy increased HDLC cholesterol significantly, while avoiding the side effects that are associated with traditional doses of niacin therapy.

Combination lipid-altering therapy: an emerging treatment paradigm for the 21st century

For the care of an expanding segment of the US population with multiple coronary risk factors, combination lipid-altering therapy is emerging as a treatment imperative. The most recent National Cholesterol Education Program's consensus guidelines emphasize long-term global coronary heart disease (CHD) risk status, designate patients with CHD risk equivalents (eg, diabetes, peripheral arterial disease, 20% or more 10-year absolute CHD risk) for aggressive lipid-altering therapy, and deem the metabolic syndrome (eg, obesity, insulin resistance, hypertension, elevated triglycerides, low levels of high-density lipoprotein cholesterol, small dense low-density lipoprotein particles) as a secondary target for intervention. With the advancing age of the US population and the high prevalence of diabetes, the metabolic syndrome, and CHD, increasing numbers of patients will require a more balanced metabolic attack attainable only through combination lipid-altering regimens. Many of these patients, as well as persons at heightened risk for cardiovascular disease because of a range of heritable conditions (eg, familial hypercholesterolemia, familial combined hyperlipidemia), will undoubtedly require binary or ternary regimens involving statins in concert with niacin, fibric-acid derivatives, or bile acid resins. Such approaches enable the clinician to exploit the complementary effects of these agents, allowing them to be administered at low, optimally tolerable doses that are consistent with superior efficacy and a lower risk of adverse events as compared with escalating doses of monotherapy.

Effective and safe modification of multiple atherosclerotic risk factors in patients with peripheral arterial disease

BACKGROUND

Patients with peripheral arterial disease (PAD) are at an increased risk of cardiovascular mortality and morbidity and thus are an excellent group in whom to evaluate the feasibility and the effect of an aggressive multifactorial intervention on atherosclerotic vascular disease risk factors. The Arterial Disease Multiple Intervention Trial (ADMIT) was designed to determine the efficacy, safety, and compliance of an multifactorial therapy on selected atherosclerotic disease risk factors in patients with PAD.

METHODS

By a 2 x 2 x 2 factorial design, eligible participants (N = 468) were randomly assigned to low-dose warfarin, antioxidant vitamins, and niacin or its corresponding placebo, and followed up for 1 year. All participants were encouraged to use aspirin. Pravastatin was added to the drug regimen for those who needed to reduce LDL cholesterol to recommended levels.

RESULTS

Niacin increased HDL cholesterol levels by 30%, with the majority of effect achieved at a dosage of 500 mg twice daily. Warfarin had an anticoagulant effect. The antioxidant vitamins resulted in a significant increase in vitamin E, C, and beta-carotene plasma levels. Overall, compliance was high and few adverse effects were reported.

CONCLUSIONS

ADMIT demonstrates that it is both feasible and safe to modify multiple atherosclerotic disease risk factors effectively with intensive combination therapy in patients with PAD.

Comparative tolerability of the HMG-CoA reductase inhibitors

The availability of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors has revolutionised the treatment of lipid abnormalities in patients at risk for the development of coronary atherosclerosis. The relatively widespread experience with HMG-CoA therapy has allowed a clear picture to emerge concerning the relative tolerability of these agents. While HMG-CoA reductase inhibitors have been shown to decrease complications from atherosclerosis and to improve total mortality, concern has been raised as to the long term safety of these agents. They came under close scrutiny in early trials because ocular complications had been seen with older inhibitors of cholesterol synthesis. However, extensive evaluation demonstrated no significant adverse alteration of ophthalmological function by the HMG-CoA reductase inhibitors. Extensive experience with the potential adverse effect of the HMG-CoA reductase inhibitors on hepatic function has accumulated. The effect on hepatic function for the various HMG-CoA reductase inhibitors is roughly dose-related and 1 to 3% of patients experience an increase in hepatic enzyme levels. The majority of liver abnormalities occur within the first 3 months of therapy and require monitoring. Rhabdomyolysis is an uncommon syndrome and occurs in approximately 0.1% of patients who receive HMG-CoA reductase inhibitor monotherapy. However, the incidence is increased when HMG-CoA reductase inhibitors are used in combination with agents that share a common metabolic path. The role of the cytochrome P450 (CYP) enzyme system in drug-drug interactions involving HMG-CoA reductase inhibitors has been extensively studied. Atorvastatin, cerivastatin, lovastatin and simvastatin are predominantly metabolised by the CYP3A4 isozyme. Fluvastatin has several metabolic pathways which involve the CYP enzyme system. Pravastatin is not significantly metabolised by this enzyme and thus has theoretical advantage in combination therapy. The major interactions with HMG-CoA reductase inhibitors in combination therapy involving rhabdomyolysis include fibric acid derivatives, erythromycin, cyclosporin and fluconazole. Additional concern has been raised relative to overzealous lowering of cholesterol which could occur due to the potency of therapy with these agents. Currently, there is no evidence from clinical trials of an increase in cardiovascular or total mortality associated with potent low density lipoprotein reduction. However, a threshold effect had been inferred by retrospective analysis of the Cholesterol and Recurrent Events study utilising pravastatin and the role of aggressive lipid therapy is currently being addressed in several large scale trials.

Current perspectives on the management of hypertriglyceridemia

BACKGROUND

Observational studies have demonstrated that triglycerides are an independent risk factor for coronary heart disease. Atherothrombosis may be mediated by uptake and incorporation of triglyceride-rich lipoproteins by macrophages and through an association with small, dense LDL and HDL particles. There are considerable data that lowering LDL cholesterol reduces cardiovascular events. However, the importance of triglyceride lowering remains elusive.

METHODS

A summary of major arteriographic and clinical end point trials is reviewed. Studies evaluating various strategies, including dietary and hygienic measures as well as pharmacologic therapies, are discussed.

RESULTS

Dietary reduction of saturated fat, coupled with aerobic activity, reduces triglyceride levels approximately 20% to 24%. Omega-3 fatty acids may also reduce triglyceride levels appreciably. Effective pharmacologic therapies that lower triglyceride levels include nicotinic acid (20% to 40%), fibrates (20% to 55%), and statins (10% to 30%). Nevertheless, an independent benefit of triglyceride lowering on coronary event rate has not been demonstrated.

CONCLUSIONS

There are little data that triglyceride reduction improves cardiovascular event rate. In contrast, lowering LDL cholesterol and, more recently, raising HDL cholesterol are proven therapies in coronary heart disease prevention. As such, these modalities remain the top priority in the management of dyslipidemia with triglyceride reduction as an adjunctive consideration.

Does differing metabolism by cytochrome p450 have clinical importance?

The cytochrome P450 (CYP) is a group of enzymes that oxidatively modify drugs to a more water-soluble form for renal excretion. Nearly 50% of all clinically used medications and endogenous steroids are metabolized by the CYP enzyme 3A4, which explains why many of the important potential drug interactions involved this enzyme. Despite an excellent safety record, CYP 3A4 statins (lovastatin, simvastatin, atorvastatin) taken concomitantly with a potent CYP 3A4 inhibitor may increase the risk for adverse events (myopathy, rhabdomyolysis). This article describes the clinical significance of CYP metabolism as the pathways relate to the use of statins, including brief discussions on statins, fibrates, cyclosporine, and calcium channel blockers. In light of these potential interactions, continued vigilance by physicians is necessary to ensure the safe use of statins.

Niacin dosing: relationship to benefits and adverse effects

Because of the original observation by Altschul et al., that nicotinic acid (niacin), not nicotinamide, in pharmacologic doses lowered human serum cholesterol levels, an avalanche of reports have been published over the past 45 years on the plasma lipid-regulating properties of this drug and its beneficial cardiovascular effects. A myriad of studies that have examined efficacy, safety, adverse effects, and pharmacologic properties of niacin rendered convincing evidence that niacin, used alone or combined with other agents, has favorable effects on serum lipoprotein regulation and on containment of atherothrombotic cardiovascular diseases. However, because of the unusual side effect profile of niacin and the availability of various formulations of this drug, niacin must be used prudently and with careful instruction and monitoring of patients. This review summarizes the pertinent and recent literature on niacin that impacts its therapeutic use. We also discuss some controversial issues and personal clinical experience and opinions on this topic.

Combination drug therapy for combined hyperlipidemia

Combination therapy for hyperlipidemia, especially combined hyperlipidemia, may have advantages over single drug therapy, affording better improvement in lipoprotein risk factors and possibly better prevention of atherothrombotic events. Although preliminary experience has been gained using treatment combinations of niacin with statins, and fibrates with statins, few studies have focused on angiographic or clinical outcomes. Both of these treatment combinations increase the risk of drug-induced myopathy and rhabdomyolysis. Current estimates of myopathy incidence are much lower than original estimates, but the relative safety of combined therapy might depend upon employing low or moderate statin doses. Safety depends critically upon educating the patient to respond appropriately to muscle symptoms, to intercurrent illness, and to concurrent use of certain other medications. Other useful drug combinations include those derived by addition of fish oil, bile acid binding resins, or stanol esters, as well as nonstatin combinations such as niacin-resin or fibrate-niacin.

Combination drug therapy for dyslipidemia

Effective treatment of dyslipidemia improves prognosis. Statin therapy has been documented to decrease the cardiovascular event rate in the setting of elevated low-density lipoprotein (LDL) cholesterol levels and coronary heart disease, but most patients are not treated to the target (LDL <or=100 mg/dL) set by the National Cholesterol Education Program. The triglyceride level is also being increasingly recognized as an important mediator in the process of progressive atherosclerosis and cardiovascular events. Studies suggest the target level for triglycerides should be the same as for LDL cholesterol levels-- no more than 100 mg/dL. In order to achieve these LDL and triglyceride levels, combination therapy is required frequently. Probably the most effective combination for mixed dyslipidemia is a statin with niacin. The use of adjunctive omega-3 supplementation also should be considered especially for patients with elevated triglyceride levels. Other adjunctive agents including sitostanol ester (in the form of a margarine) and a well-tolerated second generation bile acid sequestrant that will lower LDL cholesterol an additional 10% to 18% and will be available soon.

A population-based treat-to-target pharmacoeconomic analysis of HMG-CoA reductase inhibitors in hypercholesterolemia

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors have become the drugs of choice for the treatment of patients with hypercholesterolemia. However, one of the major concerns with these drugs is cost. In an attempt to develop a cost-effective treatment strategy for patients referred to our lipid clinic, we conducted a meta-analysis to estimate the lipid-lowering efficacy of the various HMG-CoA reductase inhibitors alone or in combination with niacin or cholestyramine. Based on cholesterol-lowering efficacy estimates derived from a literature-based meta-analysis, we performed a population-based treat-to-target analysis. Fifty-six trials with 101 monotherapy cohorts and 20 trials with 31 combination-therapy cohorts (573 patients) were included in the meta-analysis. Based on reduction in low-density lipoprotein cholesterol (LDL-C), the most effective monotherapy was atorvastatin and the least effective monotherapy was fluvastatin. Combination therapy was more effective in reducing LDL-C than monotherapy with the respective HMG-CoA reductase inhibitor. However, on the basis of dollars spent per percentage of LDL-C reduction, combination therapy was frequently less cost-effective than monotherapy. In addition, combination therapy was associated with a higher rate of noncompliance and a greater risk of drug-drug interactions. As a result, we based our treat-to-target analysis on the use of monotherapy as first-line treatment, with combination therapy reserved for patients failing to achieve the target LDL-C levels of the US National Cholesterol Education Program Adult Treatment Panel II (NCEP ATP-II) with monotherapy. In the population-based treat-to-target analysis, atorvastatin was the most cost-effective drug for high-risk patients (those with coronary heart disease [CHD]), whereas fluvastatin was the most cost-effective agent for low-risk patients (<2 risk factors for CHD) and moderate-risk patients (> or =2 risk factors for CHD). If 1 drug is chosen to treat all patients (i.e., in cases of formulary restriction), atorvastatin would be the most cost-effective agent. In adapting the findings on cholesterol-lowering efficacy from this analysis to our lipid clinic, we concluded that the most cost-effective treatment approach is to individualize the selection of an HMG-CoA reductase inhibitor based on both coronary risk and the LDL-C reduction required to achieve NCEP ATP-II goals. Based on our results, 2 agents--atorvastatin and fluvastatin--should be available on the formulary.

Clinical profiles of plain versus sustained-release niacin (Niaspan) and the physiologic rationale for nighttime dosing

Niacin is the oldest and most versatile agent in use for the treatment of dyslipidemia. It has beneficial effects on low-density lipoprotein cholesterol; high-density lipoprotein cholesterol; the apolipoproteins B and A-I constituting these fractions; triglyceride; and lipoprotein(a). Together, these benefits lead to a diminished incidence of coronary artery disease among niacin users. The chief constraints against niacin use have been flushing, gastrointestinal discomfort, and metabolic effects including hepatotoxicity. Time-release niacin has been developed in part to limit flushing, and now a nighttime formulation (Niaspan) has been developed that assists in containing this untoward effect. In a pivotal metabolic study, bed-time administration of 1.5 g time-release niacin was shown to have the same beneficial effects as 1.5 g plain niacin in 3 divided doses and to be well tolerated. Previous studies suggest that bedtime niacin administration diminishes lipolysis and release of free fatty acids to the liver; this, in turn, leads to an abolition of the usual diurnal increase in plasma triglyceride, which may result in diminished formation and secretion of triglyceride in the very-low-density lipoprotein fraction.

Treatment of hyperlipidemia with combined niacin-statin regimens

Combined use of niacin with a statin is an attractive option, since these types of medication have the best records in clinical trials for reduction in cardiovascular events and improvement in progression/regression of coronary lesions. In early use, the niacin-statin combination generated a few case reports documenting severe myopathy and rhabdomyolysis. Subsequent prospective trials in >400 patients, however, have not encountered myopathy. This experience includes 165 patients who took a statin in combination with Niaspan, a new, extended-release niacin administered once nightly. Hepatic toxicity with immediate-release niacin and with Niaspan used in combination with statins has been minimal. However, substantial transaminase elevations occurred with the use of a sustained-release niacin (Nicobid) given twice daily. The niacin-statin treatment regimens gave augmented low-density lipoprotein (LDL)-cholesterol reduction along with favorable changes in high-density lipoprotein (HDL) cholesterol, lipoprotein(a), and triglycerides. This combination therapy can be used safely as long as (1) careful attention is given to niacin formulation and dosing; (2) liver functions are monitored; and (3) patients are educated to recognize symptoms of myopathy. However, special caution should apply to use of niacin in combination with high doses of statins, or with statins introduced into clinical practice in 1997 or later, since little experience has accumulated in these circumstances.

Effectiveness of once-nightly dosing of extended-release niacin alone and in combination for hypercholesterolemia

We performed a multicenter, open-label study to determine the long-term safety and efficacy of a new extended-release once-a-night niacin preparation, Niaspan, in the treatment of hypercholesterolemia. Niaspan, 0.5 to 3.0 g once a night at bedtime, was used alone or in combination with a statin (inhibitor of hydroxymethylglutaryl coenzyme A reductase), a bile acid sequestrant, or both. Patients included 269 hypercholesterolemic male and female adults enrolled in a 96-week study, and 230 additional adults for whom short-term safety data were available. The dosages of Niaspan attained by 269 patients were 1,000 mg (95% of patients), 1,500 mg (86%), and 2,000 mg (65%). After 48 weeks of treatment, Niaspan alone (median dose 2,000 mg) reduced low-density lipaprotein (LDL) cholesterol (18%), apolipoprotein B (15%), total cholesterol (11%), triglycerides (24%), and lipoprotein(a) (36%), and increased high-density lipoprotein (HDL) cholesterol (29%). Niaspan plus a statin lowered LDL cholesterol (32%), apolipoprotein B (26%), total cholesterol (23%), triglycerides (30%), and lipoprotein(a) (19%), and increased HDL cholesterol (26%). Reversible elevations of aspartate aminotransferase or alanine aminotransferase more than twice the normal range occurred in 2.6% of patients. One patient discontinued Niaspan because of transaminase elevations. Intolerance to flushing, leading to discontinuation of Niaspan, occurred in 4.8% of patients. The overall rate of discontinuance due to flushing in this study combined with 2 previous randomized trials was 7.3%. In the long-term treatment of hypercholesterolemia, Niaspan produced favorable changes in LDL and HDL cholesterol, triglycerides, and lipoprotein(a). Adverse hepatic effects were minor and occurred at rates similar to those reported for statin therapy.

Equivalent efficacy of a time-release form of niacin (Niaspan) given once-a-night versus plain niacin in the management of hyperlipidemia

This study compared the efficacy and safety of a once-a-night, time-release niacin formulation, Niaspan (Kos Pharmaceuticals, Miami Lakes, FL), with plain niacin and placebo for the treatment of primary hypercholesterolemia. The study was conducted in nine academic lipid research clinics in a randomized, double-blind design. Niaspan 1.5 g at bedtime was compared with plain niacin 1.5 g/d after 8 weeks and 3.0 g/d after 16 weeks in divided doses and with placebo. A total of 223 hypercholesterolemic adult men and women participated. Compared with placebo at 8 weeks, Niaspan versus plain niacin at 1.5 g/d showed comparable efficacy, comparably lowering total cholesterol (C) (8%/8%), triglycerides (16%/18%), low-density lipoprotein (LDL)-C (12%/12%), apolipoprotein (apo B) (12%/12%), apo E (9%/7%), and lipoprotein(a) [Lp(a)] (15%/11%), and raising high-density lipoprotein (HDL)-C (20%/17%), HDL2-C (37%/33%), HDL3-C (17%/16%), and apo A-I (8%/6%) (P < or = .05 in all instances). After 16 weeks, the Niaspan effect on LDL-C and triglyceride was unchanged while the plain niacin effect approximately doubled. At equal doses of 1.5 g/d of Niapan versus plain niacin, respectively, AST increased 5.0% versus 4.8% (difference not significant [NS]), fasting plasma glucose increased 4.8% versus 4.5% (NS), and uric acid concentrations increased less, 6% versus 16% (P=.0001). Flushing events were more frequent with plain niacin versus Niaspan (1,905 v 576, P < .001). Flushing severity was slightly greater with Niaspan, but still well tolerated. In conclusion, Niaspan 1.5 g hour of sleep (hs) has comparable efficacy, a lower incidence of flushing, a lesser uric acid rise, and an equivalent hepatic enzyme effect than 500 mg thrice-daily plain niacin in hyperlipidemic subjects. Niaspan may be an equivalent or better alternative to plain niacin at moderate doses in the management of hyperlipidemia.

A randomized trial of the effects of atorvastatin and niacin in patients with combined hyperlipidemia or isolated hypertriglyceridemia. Collaborative Atorvastatin Study Group

BACKGROUND

To assess the lipid-lowering effects and safety of atorvastatin and niacin in patients with combined hyperlipidemia or isolated hypertriglyceridemia.

METHODS

We performed a randomized, open-label, parallel-design, active-controlled, study in eight centers in the United States. We enrolled 108 patients with total cholesterol (TC) of > or =200 mg/dL, serum triglycerides (TG) > or =200 and < or =800 mg/dL, and apolipoprotein B (apo B) > or =110 mg/dL. Patients were randomly assigned to receive atorvastatin 10 mg once daily (n=55) or immediate-release niacin 1 g three times daily for 12 weeks (n=53). Patients were stratified based on low-density lipoprotein cholesterol (LDL-C): Patients with LDL-C > or =135 mg/dL were considered to have combined hyperlipidemia and patients with LDL-C <135 mg/dL were considered to have isolated hypertriglyceridemia. The primary outcome measure was percent change from baseline in LDL-C. Other lipid levels were evaluated as secondary parameters.

RESULTS

Atorvastatin reduced LDL-C 30% and TC 26% from baseline, and increased high-density lipoprotein cholesterol (HDL-C) 4%. Total TG were reduced 17%. Niacin reduced LDL-C 2%, TC 7%, increased HDL-C 25%, and reduced total TG 29% from baseline. There was a significant difference in LDL-C reduction, the primary efficacy parameter, between the two treatment groups (P <0.05, favoring atorvastatin), as well as a significant difference in the improvement in HDL-C (P <0.05, favoring niacin). The effect of atorvastatin was relatively consistent between patients with combined hyperlipidemia and isolated hypertriglyceridemia, whereas there was more variability between these strata in the niacin treatment group. Atorvastatin was better tolerated than niacin.

CONCLUSION

Atorvastatin may allow patients with combined hyperlipidemia to be treated with monotherapy and offers an efficacious and well-tolerated alternative to niacin for the treatment of patients with isolated hypertriglyceridemia.

Comparison of pravastatin with crystalline nicotinic acid monotherapy in treatment of combined hyperlipidemia

Pravastatin treatment of combined hyperlipidemia lowers low-density lipoprotein effectively; nicotinic acid lowers remnant cholesterol and raises high-density lipoprotein. A combination of these 2 drugs may be indicated for optimal treatment of lipoprotein abnormalities in combined hyperlipidemia.

Pravastatin. A reappraisal of its pharmacological properties and clinical effectiveness in the management of coronary heart disease

Pravastatin is an HMG-CoA reductase inhibitor which lowers plasma cholesterol levels by inhibiting de novo cholesterol synthesis. Pravastatin produces consistent dose-dependent reductions in both total and low density lipoprotein (LDL)-cholesterol levels in patients with primary hypercholesterolaemia. Favourable changes in other parameters such as total triglyceride and high density lipoprotein (HDL)-cholesterol levels are generally modest. Combination therapy with other antihyperlipidaemic agents such as cholestyramine further enhances the efficacy of pravastatin in patients with severe dyslipidaemias. Available data suggest that pravastatin is effective in elderly patients and in patients with hypercholesterolaemia secondary to diabetes mellitus or renal disease. The benefit of cholesterol-lowering in terms of patient outcomes is currently an area of considerable interest. Recently completed regression studies (PLAC I, PLAC II, KAPS and REGRESS) show that pravastatin slows progression of atherosclerosis and lowers the incidence of coronary events in patients with mild to moderately severe hypercholesterolaemia and known coronary heart disease. Large scale primary (WOSCOPS) and secondary (CARE) prevention studies, moreover, demonstrate that pravastatin has beneficial effects on coronary morbidity and mortality. In WOSCOPS, all-cause mortality was reduced by 22%. Pravastatin is generally well tolerated by most patients (including the elderly), as evidenced by data from studies of up to 5 years in duration. As with other HMG-CoA reductase inhibitors, myopathy occurs rarely (< 0.1% of patients treated with pravastatin): approximately 1 to 2% of patients may present with raised serum levels of hepatic transaminases. Thus, with its favourable effects on cardiovascular morbidity/mortality and total mortality, pravastatin should be considered a first-line agent in patients with elevated cholesterol levels, multiple risk factors or coronary heart disease who are at high risk of cardiovascular morbidity.

Effectiveness and safety of low-dose pravastatin and squalene, alone and in combination, in elderly patients with hypercholesterolemia

A double-blind, placebo-controlled study was conducted to compare the efficacy and safety of low-dose (10 mg) prevastatin and squalene (860 mg), either alone or in combination therapy, with placebo in the treatment of elderly patients with hypercholesterolemia. Ambulatory elderly patients (N = 102) were assigned in randomized fashion to receive active treatment or placebo for 20 weeks after a single-blind placebo lead-in period of 8 weeks. Total cholesterol and triglyceride levels in plasma were at least 250 mg/dL and less than 300 mg/dL, respectively. Concentrations of lipids and lipoproteins were measured, and clinical laboratory tests included liver function and creatine kinase determinations. Pravastatin 10 mg daily was more effective than squalene in reducing total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides and in increasing levels of high-density lipoprotein (HDL) cholesterol. Combination therapy significantly reduced total cholesterol and LDL cholesterol and increased HDL cholesterol to a greater extent than either drug alone. Adverse events and clinical laboratory abnormalities were generally mild and transient in all groups, and all but two patients finished the study. The incidence of side effects was low; myopathy did not occur. Coadministration of pravastatin and squalene combined the specific effects of the two drugs on lipoprotein concentrations. This combination may be useful and more cost-effective in elderly patients with hypercholesterolemia, who might have a higher incidence of side effects when using larger doses of pravastatin alone.

Efficacy and Tolerability of Low-dose Simvastatin and Niacin, Alone and in Combination, in Patients With Combined Hyperlipidemia: A Prospective Trial

BACKGROUND: Combination lipid-lowering therapy may be desirable in patients with elevated low-density lipoprotein cholesterol, high triglycerides, and low high-density lipoprotein cholesterol. This study was conducted to determine the lipid-lowering efficacy of the combination of low-dose simvastatin and niacin in patients with combined hyperlipidemia and low high-density lipoprotein cholesterol. METHODS AND RESULTS: In this multicenter, prospective, randomized trial, 180 patients with hypercholesterolemia and hypertriglyceridemia and/or low high-density lipoprotein cholesterol were randomized to combination simvastatin (10 mg/day) and niacin (0.75 g/day) or to either drug alone for 9 weeks. The dose of niacin was doubled (from 0.75 g/day to 1.5 g/day) in both the combination and niacin arms for the remaining 8 weeks. The combination of simvastatin, 10 mg/day, and niacin, 1.5 g/day, reduced total, low-density lipoprotein, and very low-density lipoprotein cholesterol and triglycerides by 24%, 29%, 45%, and 31%, respectively, while increasing high-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol-lowering effect of simvastatin; however, the combination was more effective than either monotherapy at raising high-density lipoprotein cholesterol and lowering very low-density lipoprotein cholesterol (P <.05). More patients discontinued treatment because of an adverse event in the niacin (P <.03) and combination groups (P =.06) than the simvastatin group. CONCLUSIONS: Treatment of patients with combined hyperlipidemia and/or low high-density lipoprotein with combination low-dose simvastatin and niacin resulted in large reductions in total, low-density lipoprotein, and very low-density lipoprotein cholesterol and increases in HDL cholesterol. Although the combination was well tolerated in the current trial, its safety needs to be evaluated in larger trials of longer duration.

Drug therapy for hypercholesterolemia in patients with cardiovascular disease: factors limiting achievement of lipid goals

PURPOSE

To determine the extent that goal lipid levels derived from the National Cholesterol Education Program (NCEP) are achievable in clinical practice, and to identify factors associated with the achievement of these goals.

PATIENTS AND METHODS

We conducted a retrospective cohort study consisting of a consecutive sample of 244 patients with either coronary artery disease or peripheral vascular disease treated for hypercholesterolemia at a large Veterans Affairs medical center. Primary outcomes, recorded prospectively, were lipid levels and lipoprotein cholesterol response, and tolerance and compliance to drug therapy. Goal lipid levels were defined as low-density lipoprotein cholesterol (LDL-C) < or = 130 mg/dL and triglyceride (TG) < or = 200 mg/dL.

RESULTS

Lipid-lowering drug therapy reduced LDL-C from 25% to 42% below baseline in patients with hypercholesterolemia varying from mild (130 to 160 mg/dL) to severe ( > 220 mg/dL), respectively. Approximately 75% of patients with LDL-C < or = 160 mg/dL ultimately achieved their lipid goal with drug therapy; however, less than half of patients with baseline LDL-C > 160 mg/dL achieved target lipid values. Multivariate analysis indicated that lower baseline LDL-C and triglycerides, use of combinations of drug therapy rather than monotherapy, and patient adherence to treatment predicted the achievement of goal lipid levels.

CONCLUSIONS

Successful implementation of NCEP guidelines, frequently requires combination drug therapies, and is limited by poor patient tolerance and acceptance of niacin and the sequestrants.

Treatment of Dyslipidemias

OBJECTIVE

To summarize recommended treatment strategies for various dyslipidemias.

METHODS

The basic pathways of lipoprotein metabolism are reviewed, and the potential for interventional alterations to correct specific dyslipidemias is outlined. Guidelines for treatment based on published clinical trials, including the consensus report of the National Cholesterol Education Program, are discussed.

RESULTS

The nonpharmacologic options of diet and exercise are important elements in the treatment of dyslipidemias. In most patients, a reduced dietary intake of fat (particularly saturated fat) should be maintained for 3 months before drug therapy is initiated. The various mechanisms of action of the bile acid resins, niacin, hydroxy-methylglutaryl-coenzyme A reductase inhibitors, and fibric acid derivatives are described, and their roles in monotherapy or combination therapy for hypercholesterolemia, combined hyperlipidemia, and hypertriglyceridemia are examined.

CONCLUSION

With an understanding of the metabolic pathways responsible for the production and removal of lipoproteins and an overview of results of previous pharmacologic interventions, clinicians can optimize lipid-lowering treatment in individual patients with dyslipidemia.