Comparison of the efficacy and safety of a combination tablet of niacin extended-release and simvastatin with simvastatin 80 mg monotherapy: the SEACOAST II (high-dose) study

Niacin-induced flushing: Mechanism, pathophysiology, and future perspectives

Flushing is a typical physiological reaction to high emotional reactions. It is characterized by cutaneous vasodilation and a feeling of warmth and skin redness, especially in the face areas. Flushing is frequently linked to social anxiety, but it can also be a sign of a number of benign and malignant medical disorders. The study focuses on niacin-induced flushing, a well-researched side effect of the niacin, a drug which increases cholesterol levels. Niacin-induced flushing occurs when the hydroxycarboxylic acid receptor 2 (HCA2 or GPR109A) is activated. This starts a signaling cascade that releases prostaglandins, especially PGD2, which causes cutaneous vasodilation. Furthermore, niacin directly interacts with the transient receptor potential (TRP) channel TRPV1, offering a different, non-prostaglandin-based explanation for flushing brought on by niacin, highlighting the intricate physiological mechanisms behind this widespread occurrence. The review delves deeper into the advantages of niacin treatment for the cardiovascular system, highlighting how it can improve lipid profiles and lower cardiovascular events when used with statins. To sum it up, this study offers a thorough understanding of flushing, including its physiological foundation, many etiologies, diagnostic difficulties, and the subtleties of flushing caused by niacin. The investigation of innovative dose forms and nanomedicine highlights the continuous endeavors to improve patient compliance and reduce side effects, laying the groundwork for further developments in flushing treatment.

Emerging Pharmacotherapy to Reduce Elevated Lipoprotein(a) Plasma Levels

Lipoprotein(a) is a unique form of low-density lipoprotein. It is associated with a high incidence of premature atherosclerotic disease such as coronary artery disease, myocardial infarction, and stroke. Plasma levels of this lipoprotein and its activities are highly variable. This is because of a wide variability in the size of the apolipoprotein A moiety, which is determined by the number of repeats of cysteine-rich domains known as "kringles." Although the exact mechanism of lipoprotein(a)-induced atherogenicity is unknown, the lipoprotein has been found in the arterial walls of atherosclerotic plaques. It has been implicated in the formation of foam cells and lipid deposition in these plaques. Pharmacologic management of elevated levels of lipoprotein(a) with statins, fibrates, or bile acid sequestrants is ineffective. The newer and emerging lipid-lowering agents, such as the second-generation antisense oligonucleotides, cholesteryl ester transfer protein inhibitors, and proprotein convertase subtilisin/kexin type 9 inhibitors offer the most effective pharmacologic therapy.

Effects of Non-statin Lipid-Modifying Agents on Cardiovascular Morbidity and Mortality Among Statin-Treated Patients: A Systematic Review and Network Meta-Analysis

Background: Currently, there is a lack of information on the comparative efficacy and safety of non-statin lipid-lowering agents (NST) in cardiovascular (CV) disease risk reduction when added to background statin therapy (ST). This study determine the relative treatment effects of NST on fatal and non-fatal CV events among statin-treated patients.

Methods: A network meta-analysis based on a systematic review of randomized controlled trials (RCTs) comparing non-statin lipid-modifying agents among statin-treated patients was performed. PubMed, EMBASE, CENTRAL, and Clinicaltrial.gov were searched up to April 10, 2018. The primary outcomes were CV and all-cause mortalities. Secondary CV outcomes were coronary heart disease (CHD) death, non-fatal myocardial infarction (MI), any stroke, and coronary revascularization. Risks of discontinuations were secondary safety outcomes.

Results: Sixty-seven RCTs including 259,429 participants with eight interventions were analyzed. No intervention had significant effects on the primary outcomes (CV mortality and all-cause mortality). For secondary endpoints, proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK) plus statin (PCSK/ST) significantly reduced the risk of non-fatal MI (RR 0.82, 95% CI 0.72–0.93, p = 0.003), stroke (RR 0.74, 95% CI 0.65–0.85, p < 0.001), coronary revascularization (RR 0.84, 95% CI 0.75–0.94, p = 0.003) compared to ST. Combinations of ST and all NST except PCSK and ezetimibe showed higher rate of discontinuation due to adverse events compared to ST.

Conclusions: None of NST significantly reduced CV or all-cause death when added to ST. PCSKs and to a lesser extent, ezetimibe may help reduce cardiovascular events with acceptable tolerability profile among broad range of patients.

Niacin for primary and secondary prevention of cardiovascular events

BACKGROUND

Nicotinic acid (niacin) is known to decrease LDL-cholesterol, and triglycerides, and increase HDL-cholesterol levels. The evidence of benefits with niacin monotherapy or add-on to statin-based therapy is controversial.

OBJECTIVES

To assess the effectiveness of niacin therapy versus placebo, administered as monotherapy or add-on to statin-based therapy in people with or at risk of cardiovascular disease (CVD) in terms of mortality, CVD events, and side effects.

SEARCH METHODS

Two reviewers independently and in duplicate screened records and potentially eligible full texts identified through electronic searches of CENTRAL, MEDLINE, Embase, Web of Science, two trial registries, and reference lists of relevant articles (latest search in August 2016).

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that either compared niacin monotherapy to placebo/usual care or niacin in combination with other component versus other component alone. We considered RCTs that administered niacin for at least six months, reported a clinical outcome, and included adults with or without established CVD.

DATA COLLECTION AND ANALYSIS

Two reviewers used pre-piloted forms to independently and in duplicate extract trials characteristics, risk of bias items, and outcomes data. Disagreements were resolved by consensus or third party arbitration. We conducted random-effects meta-analyses, sensitivity analyses based on risk of bias and different assumptions for missing data, and used meta-regression analyses to investigate potential relationships between treatment effects and duration of treatment, proportion of participants with established coronary heart disease and proportion of participants receiving background statin therapy. We used GRADE to assess the quality of evidence.

MAIN RESULTS

We included 23 RCTs that were published between 1968 and 2015 and included 39,195 participants in total. The mean age ranged from 33 to 71 years. The median duration of treatment was 11.5 months, and the median dose of niacin was 2 g/day. The proportion of participants with prior myocardial infarction ranged from 0% (4 trials) to 100% (2 trials, median proportion 48%); the proportion of participants taking statin ranged from 0% (4 trials) to 100% (12 trials, median proportion 100%).Using available cases, niacin did not reduce overall mortality (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.97 to 1.12; participants = 35,543; studies = 12; I2 = 0%; high-quality evidence), cardiovascular mortality (RR 1.02, 95% CI 0.93 to 1.12; participants = 32,966; studies = 5; I2 = 0%; moderate-quality evidence), non-cardiovascular mortality (RR 1.12, 95% CI 0.98 to 1.28; participants = 32,966; studies = 5; I2 = 0%; high-quality evidence), the number of fatal or non-fatal myocardial infarctions (RR 0.93, 95% CI 0.87 to 1.00; participants = 34,829; studies = 9; I2 = 0%; moderate-quality evidence), nor the number of fatal or non-fatal strokes (RR 0.95, 95% CI 0.74 to 1.22; participants = 33,661; studies = 7; I2 = 42%; low-quality evidence). Participants randomised to niacin were more likely to discontinue treatment due to side effects than participants randomised to control group (RR 2.17, 95% CI 1.70 to 2.77; participants = 33,539; studies = 17; I2 = 77%; moderate-quality evidence). The results were robust to sensitivity analyses using different assumptions for missing data.

AUTHORS' CONCLUSIONS

Moderate- to high-quality evidence suggests that niacin does not reduce mortality, cardiovascular mortality, non-cardiovascular mortality, the number of fatal or non-fatal myocardial infarctions, nor the number of fatal or non-fatal strokes but is associated with side effects. Benefits from niacin therapy in the prevention of cardiovascular disease events are unlikely.

Effects of Extended-Release Niacin and Extended-Release Niacin/Laropiprant on the Pharmacokinetics of Simvastatin in Healthy Subjects

The use of multiple lipid-modifying agents with different mechanisms of action is often required to regulate lipid levels in patients with dyslipidemia. During combination therapy, alterations in the pharmacokinetics of any of the drugs used and their metabolites may occur. Three separate open-label, randomized, crossover studies evaluated the potential for pharmacokinetic interaction between extended-release niacin (with and without concomitant laropiprant) and simvastatin in healthy subjects. Study 1 used single doses of extended-release niacin and simvastatin; study 2 used multiple-dose coadministration of extended-release niacin/laropiprant and simvastatin in healthy subjects; and study 3 used single doses of both extended-release niacin and the coadministration of extended-release niacin/laropiprant and simvastatin in healthy Chinese subjects. During each treatment period, plasma samples were collected predose and at prespecified postdose time points for pharmacokinetic analyses. The safety and tolerability of simvastatin with and without coadministered extended-release niacin (or extended-release niacin/laropiprant) were assessed by clinical evaluation of adverse experiences. In 2 studies in healthy subjects, modest increases in exposure to simvastatin acid (by ∼60%) by extended-release niacin and extended-release niacin/laropiprant were observed. Based on the clinical experience with simvastatin, these effects are not believed to be clinically meaningful. In the third study on healthy Chinese subjects, no statistically meaningful increases in exposure to simvastatin by extended-release niacin and extended-release niacin/laropiprant were observed. In all populations examined in these studies, the coadministration of extended-release niacin and simvastatin was generally well tolerated.

Lipoprotein(a), cardiovascular disease, and contemporary management

Elevated lipoprotein(a) (Lp[a]) is a causal genetic risk factor for cardiovascular disease. To determine if current evidence supports both screening and treatment for elevated Lp(a) in high-risk patients, an English-language search of PubMed and MEDLINE was conducted. In population studies, there is a continuous association between Lp(a) concentrations and cardiovascular risk, with synergistic effects when low-density lipoprotein (LDL) is also elevated. Candidates for Lp(a) screening include patients with a personal or family history of premature cardiovascular disease, familial hypercholesterolemia, recurrent cardiovascular events, or inadequate LDL cholesterol (LDL-C) responses to statins. Given the comparative strength of clinical evidence, reducing LDL-C to the lowest attainable value with a high-potency statin should be the primary focus of lipid-modifying therapies. If the Lp(a) level is 30 mg/dL or higher in a patient who has the aforementioned characteristics plus residual LDL-C elevations (≥70-100 mg/dL) despite maximum-potency statins or combination statin therapy, the clinician may consider adding niacin (up to 2 g/d). If, after these interventions, the patient has progressive coronary heart disease (CHD) or LDL-C levels of 160-200 mg/dL or higher, LDL apheresis should be contemplated. Although Lp(a) is a major causal risk factor for CHD, no currently available controlled studies have suggested that lowering it through either pharmacotherapy or LDL apheresis specifically and significantly reduces coronary risk. Further research is needed to (1) optimize management in order to reduce CHD risk associated with elevated Lp(a) and (2) determine what other intermediate- or high-risk groups might benefit from Lp(a) screening.

The current state of niacin in cardiovascular disease prevention: a systematic review and meta-regression

OBJECTIVES

This study sought to assess the efficacy of niacin for reducing cardiovascular disease (CVD) events, as indicated by the aggregate body of clinical trial evidence including data from the recently published AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes) trial.

BACKGROUND

Previously available randomized clinical trial data assessing the clinical efficacy of niacin has been challenged by results from AIM-HIGH, which failed to demonstrate a reduction in CVD event incidence in patients with established CVD treated with niacin as an adjunct to intensive simvastatin therapy.

METHODS

Clinical trials of niacin, alone or combined with other lipid-altering therapy, were identified via MEDLINE. Odds ratios (ORs) for CVD endpoints were calculated with a random-effects meta-analyses. Meta-regression modeled the relationship of differences in on-treatment high-density lipoprotein cholesterol with the magnitude of effect of niacin on CVD events.

RESULTS

Eleven eligible trials including 9,959 subjects were identified. Niacin use was associated with a significant reduction in the composite endpoints of any CVD event (OR: 0.66; 95% confidence interval [CI]: 0.49 to 0.89; p = 0.007) and major coronary heart disease event (OR: 0.75; 95% CI: 0.59 to 0.96; p = 0.02). No significant association was observed between niacin therapy and stroke incidence (OR: 0.88; 95% CI: 0.5 to 1.54; p = 0.65). The magnitude of on-treatment high-density lipoprotein cholesterol difference between treatment arms was not significantly associated with the magnitude of the effect of niacin on outcomes.

CONCLUSIONS

The consensus perspective derived from available clinical data supports that niacin reduces CVD events and, further, that this may occur through a mechanism not reflected by changes in high-density lipoprotein cholesterol concentration.

A review of the rationale for additional therapeutic interventions to attain lower LDL-C when statin therapy is not enough

Statins alone are not always adequate therapy to achieve low-density lipoprotein (LDL) goals in many patients. Many options are available either alone or in combination with statins that makes it possible to reach recommended goals in a safe and tolerable fashion for most patients. Ezetimibe and bile acid sequestrants reduce cholesterol transport to the liver and can be used in combination. Niacin is very effective at lowering LDL, beyond its ability to raise high-density lipoprotein and shift LDL particle size to a less atherogenic type. When statins cannot be tolerated at all, red yeast rice can be used if proper formulations of the product are obtained. Nutrients can also be added to the diet, including plant stanols and sterols, soy protein, almonds, and fiber, either individually or all together as a portfolio diet. A clear understanding of how each of these strategies works is essential for effective results.

Attenuation of niacin-induced prostaglandin D(2) generation by omega-3 fatty acids in THP-1 macrophages and Langerhans dendritic cells

Niacin, also known as nicotinic acid, is an organic compound that has several cardio-beneficial effects. However, its use is limited due to the induction of a variable flushing response in most individuals. Flushing occurs from a niacin receptor mediated generation of prostaglandins from arachidonic acid metabolism. This study examined the ability of docosahexaenoic acid, eicosapentaenoic acid, and omega-3 polyunsaturated fatty acids (PUFAs), to attenuate niacin-induced prostaglandins in THP-1 macrophages. Niacin induced both PGD₂ and PGE₂ generation in a dose-dependent manner. Niacin also caused an increase in cytosolic calcium and activation of cytosolic phospholipase A₂. The increase in PGD₂ and PGE₂ was reduced by both docosahexaenoic acid and eicosapentaenoic acid, but not by oleic acid. Omega-3 PUFAs efficiently incorporated into cellular phospholipids at the expense of arachidonic acid, whereas oleic acid incorporated to a higher extent but had no effect on arachidonic acid levels. Omega-3 PUFAs also reduced surface expression of GPR109A, a human niacin receptor. Furthermore, omega-3 PUFAs also inhibited the niacin-induced increase in cytosolic calcium. Niacin and/or omega-3 PUFAs minimally affected cyclooxygenase-1 activity and had no effect on cyclooxygenase -2 activity. The effects of niacin on PGD₂ generation were further confirmed using Langerhans dendritic cells. Results of the present study indicate that omega-3 PUFAs reduced niacin-induced prostaglandins formation by diminishing the availability of their substrate, as well as reducing the surface expression of niacin receptors. In conclusion, this study suggests that the regular use of omega-3 PUFAs along with niacin can potentially reduce the niacin-induced flushing response in sensitive patients.

Niacin extended release (ER)/simvastatin (Simcor®): a guide to its use in lipid regulation

Oral fixed-dose niacin extended release/simvastatin is associated with clinically relevant improvements in plasma lipid profiles, including lowering of non-high-density lipoprotein cholesterol levels, relative to simvastatin monotherapy in patients with mixed dyslipidemias who had not responded fully to simvastatin monotherapy, and is generally well tolerated.

Extended release niacin-laropiprant in patients with hypercholesterolemia or mixed dyslipidemias improves clinical parameters

The progression of atherosclerosis remains a major cause of morbidity and mortality. Plaque formation is an immunological response driven by a number of risk factors, and reduction of risk is the primary goal of treatment. The role of LDL-C is well established and statins have proved effective drugs, although the relative risk reduction is only around 30%. The importance of other factors-notably low HDL-C and high TGs-has become increasingly clear and the search for alternative strategies continues. Niacin is particularly effective in achieving normalization of HDL-C but is clinically underutilized due to the side effect of cutaneous flushing. The discovery that flushing is mediated by mechanisms distinct from the lipid-lowering effects has led to the development of combination drugs with reduced side effects. This review considers the evidence regarding the clinical efficacy of extended-release niacin and the DP1 antagonist laropiprant in the treatment of hypercholesterolemia and mixed dyslipidemias.

Niacin extended-release therapy in phase III clinical trials is associated with relatively low rates of drug discontinuation due to flushing and treatment-related adverse events: a pooled analysis

BACKGROUND AND OBJECTIVE

Niacin is a highly effective agent for increasing low high-density lipoprotein cholesterol (HDL-C) levels. It also has beneficial effects on key pro-atherogenic lipoprotein parameters. However, the side effect of flushing can challenge patient adherence to treatment. In this study, we pooled safety data from available trials of at least 16 weeks' duration to evaluate the impact of flushing on patient adherence to niacin extended-release (NER) therapy.

METHODS

Data were pooled from eight NER studies (administered as NER with a maximum dosage of 1000, 1500, and 2000 mg/day, either as monotherapy or in combination with simvastatin 20 or 40 mg/day [NER/S], or lovastatin 20 or 40 mg/day [NER/L]) to evaluate rates of study discontinuation due to flushing or any treatment-related adverse events.

RESULTS

While 66.6% of patients experienced flushing, only 5.2% of patients discontinued treatment due to flushing. Of the total number of patients treated with NER (n = 307), NER/S (n = 912), or NER/L (n = 928), 34 (11%), 105 (11%), and 127 (14%) patients discontinued due to any treatment-related adverse event, respectively, while 14 (5%), 43 (5%), and 55 (6%) discontinued due to flushing. Discontinuation for flushing did not differ with regard to maximum dose, or to the presence or type of statin combined with NER.

CONCLUSION

Although flushing was common with NER treatment, discontinuation due to flushing occurred in only 5-6% of patients in this pooled analysis. This could be due to several factors, including the fact that all patients in the NER trials were educated about flushing and its management. Translation of methodology employed in these trials into clinical practice may improve long-term adherence to NER therapy, which would enhance the therapeutic benefit of NER for reducing cardiovascular risk.

Assessment of potential pharmacokinetic interactions of ezetimibe/simvastatin and extended-release niacin tablets in healthy subjects

BACKGROUND

Efforts to lower plasma lipid levels sometimes require multiple agents with different mechanisms of action to achieve results specified by national treatment guidelines.

METHODS

This was an open-label, randomized, three-period, multiple-dose crossover study that assessed the potential for pharmacokinetic interaction between extended-release niacin and ezetimibe/simvastatin and their major metabolites. Eighteen adults received three randomized treatments: (A) extended-release (ER) niacin 1000 mg/day for 2 days, followed by 2000 mg/day for 5 days; (B) ezetimibe/simvastatin 10 mg/20 mg/day; (C) coadministration of Treatments A and B. Treatments were given once a day after a low fat breakfast for a total of 7 days, with a 7-day inter-dose period.

RESULTS

There were small (mean ≤35%) increases in drug exposure for all analytes after coadministration of ER niacin and ezetimibe/simvastatin 10 mg/20 mg. The least-square mean between treatment C(max) (maximum plasma concentration) ratios (×100) were 97, 98, and 109% for ezetimibe, simvastatin and niacin, respectively. The corresponding ratios for total ezetimibe, simvastatin acid, and nicotinuric acid were 99, 118, and 110%. The AUC((0-24)) (area under the plasma concentration-time curve from time zero to 24 h after dosing) ratios for ezetimibe, simvastatin, and niacin were 109, 120, and 122%, respectively, and the corresponding ratios for total ezetimibe, simvastatin acid, and nicotinuric acid were 126, 135 and 119%.

CONCLUSION

There is a small pharmacokinetic drug interaction between ER niacin and ezetimibe/simvastatin and although this is not considered to be clinically significant, the concomitant use of these drugs should be appropriately monitored, especially during the niacin titration period.

'Trig-onometry': non-high-density lipoprotein cholesterol as a therapeutic target in dyslipidaemia

Targeting elevations in low-density lipoprotein cholesterol (LDL-C) remains the cornerstone of cardiovascular prevention. However, this fraction does not adequately capture elevated triglyceride-rich lipoproteins (TRLs; e.g. intermediate-density lipoprotein, very low density lipoprotein) in certain patients with metabolic syndrome or diabetic dyslipidaemia. Many such individuals have residual cardiovascular risk that might be lipid/lipoprotein related despite therapy with first-line agents (statins). Epidemiological evidence encompassing > 100,000 persons supports the contention that non-high-density lipoprotein cholesterol (non-HDL-C) is a superior risk factor vs. LDL-C for incident coronary heart disease (CHD) in certain patient populations. In studies with clinical end-points evaluated in the current article, a 1:1 to 1:3 relationship was observed between reductions in non-HDL-C and in the relative risk of CHD after long-term treatment with statins, niacin (nicotinic acid) and fibric-acid derivatives (fibrates); this relationship increased to 1:5 to 1:10 in smaller subgroups of patients with elevated triglycerides and low HDL-C levels. Treatment with statin-, niacin-, fibrate-, ezetimibe-, and omega 3 fatty acid-containing regimens reduced non-HDL-C by approximately 9-65%. In a range of clinical trials, long-term treatment with these agents also significantly decreased the incidence of clinical/angiographic/imaging efficacy outcome variables. For patients with dyslipidaemia, consensus guidelines have established non-HDL-C treatment targets 30 mg/dl higher than LDL-C goals. Ongoing prospective randomised controlled trials should help to resolve controversies concerning (i) the clinical utility of targeting non-HDL-C in patients with dyslipidaemia; (ii) the most efficacious and well-tolerated therapies to reduce non-HDL-C (e.g. combination regimens); and (iii) associations between such reductions and clinical, angiographic, and/or imaging end-points.

Treating mixed hyperlipidemia and the atherogenic lipid phenotype for prevention of cardiovascular events

Statins reduce cardiovascular events and cardiovascular and total mortality in persons at risk for and with coronary disease, but there remains a significant residual event rate, particularly in those with the atherogenic lipid phenotype that is characterized by a low high-density lipoprotein (HDL) cholesterol and increase in non-HDL cholesterol. Large outcome trials designed to assess the value of combining statins with other agents to target HDL cholesterol and non-HDL cholesterol will not be completed for a few years, but there is ample evidence for the clinician to consider combination therapy. The choices for therapies to supplement statins include niacin, fibrates, and omega-3 fatty acids. We present the argument that after therapeutic lifestyle changes, the first priority should be the maximally tolerated effective dose of a potent statin. Evidence supports the addition of niacin as the second agent. In some situations, high-dose omega-3 fatty acid therapy could be the first agent added to statins. Although fibrate monotherapy alone or in combination with non-statin low-density lipoprotein cholesterol-lowering agents can be effective in mixed hyperlipidemia when statins are not tolerated, the combination of statin+fibrate should be considered second-line therapy until the efficacy and safety are established.

A new paradigm for managing dyslipidemia with combination therapy: laropiprant + niacin + simvastatin

IMPORTANCE OF THE FIELD

Despite effective lowering of low-density lipoprotein cholesterol (LDL-C) with statin for prevention of cardiovascular adverse events, residual risk remains high due to low high-density lipoprotein cholesterol (HDL-C) levels in patients with mixed dyslipidemia. As a result, alternative treatment options to raise HDL-C are being investigated intensively. Currently, niacin is the most potent lipid lowering agent for raising HDL-C levels together with lowering of triglyceride and LDL-C. Previous clinical studies have demonstrated that niacin therapy significantly reduces the risk of cardiovascular events in high risk subjects. However, the clinical use of niacin is limited by its major adverse effect, cutaneous flushing. Although the use of extended-release (ER) formulation can reduce flushing, the tolerability and compliance of niacin remains suboptimal. A selective antagonist of prostaglandin D Type 1 receptor, laropiprant, has been investigated in a number of clinical studies and shown to be effective in reducing niacin-induced flushing. Despite the potential of laropiprant in reducing niacin-induced flushing, the long-term clinical efficacy and potential off-target side effects are not well studied. AREAS COVERED IN THIS REVIEWS: In this article, the pharmacological properties, clinical efficacy and future perspective of this combination therapy of simvastatin/ER niacin/laropiprant are reviewed.

WHAT THE READER WILL GAIN

Readers will understand both the mechanism and clinical effects of the combination therapy of simvastatin/ER niacin/laropiprant.

TAKE HOME MESSAGE

The triple combination therapy of simvastatin/ER niacin/laropiprant may reduce flushing side effects and facilitate a more comprehensive treatment for patients with mixed dyslipidemia.

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.

Niacin, an old drug with new perspectives for the management of dyslipidaemia

Niacin has been used for decades to treat dyslipidaemic disorders. Niacin is the most effective agent currently available for increasing levels of high-density lipoprotein. Moreover, significant improvements in cardiovascular outcomes in niacin treated patients have been demonstrated. However, tolerability concerns, particularly flushing, have limited its use in the past. Therefore, ER niacin, a prolonged-release formulation of niacin, has been developed with similar efficacy but a superior tolerability profile compared to the immediate-release formulations. Recent insights on niacin mechanisms of action have led to the development of a new agent called laropiprant. Laropiprant selectively blocks the binding of prostaglandin D2 to its receptor (DP1) in dermal capillaries, which mediates niacin-induced vasodilation. When co-administered with ER niacin, a marked reduction in ER niacin induced flushing is seen.The clinical use of niacin and the novel flush-reducing co-medication, will be discussed.

The mechanism and mitigation of niacin-induced flushing

AIMS

To summarise the metabolic responses to niacin that can lead to flushing and to critically evaluate flushing mitigation research.

METHODS AND RESULTS

This comprehensive review of the mechanism of action of niacin-induced flushing critically evaluates research regarding flushing mitigating formulations and agents. Niacin induces flushing through dermal Langerhans cells where the activation of G protein-coupled receptor 109A (GPR109A) increases arachidonic acid and prostaglandins, such as prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)), subsequently activating prostaglandin D(2) receptor (DP(1)), prostaglandin E(2) receptor (EP(2)) and prostaglandin E receptor 4 (EP(4)) in capillaries and causing cutaneous vasodilatation. Controlling niacin absorption rates, inhibiting prostaglandin production, or blocking DP(1), EP(2) and EP(4) receptors can inhibit flushing. Niacin extended-release (NER) formulations have reduced flushing incidence, duration and severity relative to crystalline immediate-release niacin with similar lipid efficacy. Non-steroidal anti-inflammatory drugs (NSAIDs), notably aspirin given 30 min before NER at bedtime, further reduce flushing. An antagonist to the DP(1) receptor (laropiprant) combined with an ER niacin formulation can reduce flushing; however, significant residual flushing occurs with clinically-relevant dosages.

CONCLUSIONS

Niacin is an attractive option for treating dyslipidemic patients, and tolerance to niacin-induced flushing develops rapidly. Healthcare professionals should particularly address flushing during niacin dose titration.

Management of complex lipid abnormalities with a fixed dose combination of simvastatin and extended release niacin

ER niacin combined with simvastatin provides an additional option for achieving LDL-C and non-HDL-C goals for cardiovascular prevention, with greater efficacy in those with triglyceride levels >200 mg/dL. ER niacin 1000 mg combined with simvastatin 20 mg reduced LDL-C by 6%, non-HDL-C by 7%, and triglycerides by 13%, and raised HDL-C by 11% compared to simvastatin 20 mg alone. The 2000 mg dose combined with simvastatin 20 to 40 mg raised reduced LDL-C by 7% to 24%, non-HDL-C by 16% to 28%, and triglycerides by 23% to 34%, and increased HDL-C by 18% to 22% compared to similar dose simvastatin therapy. While cardiovascular risk is reduced in proportion to the magnitude of LDL-C lowering, the additive benefit of raising HDL-C and lowering triglycerides remains to be determined. ER niacin-simvastatin is reasonably well tolerated, with a <7% discontinuation rate due to flushing in patients who used aspirin or non-steroidal anti-inflammatory medications as needed. However, drop-out rates were high in both the simvastatin and ER niacin-simvastatin treatment groups in both the 24- and 52-week studies. The safety profile of the combination appears to be similar to that of niacin and simvastatin used as monotherapies. Results of ongoing morbidity/mortality trials of ER niacin added to statin therapy are eagerly awaited.

Fixed-dose combination of extended-release niacin plus simvastatin for lipid disorders

Coronary heart disease (CHD) carries significant morbidity and mortality worldwide. Elevated LDL-cholesterol and reduced HDL-cholesterol levels are well-recognized CHD risk factors. Despite guideline recommendations for intensive therapy among patients at high risk for CHD to lower LDL-cholesterol, such lowering has failed to prevent approximately two-thirds of cardiovascular events. As a result of new data, guidelines have begun to focus on non-HDL-cholesterol, HDL-cholesterol and triglycerides as treatment targets, with the end result being a recommendation for combination therapy, such as niacin plus statin for the treatment of dyslipidemia. Compared with statin monotherapy, a combination of niacin and statin therapy provides beneficial effects on a broad range of lipid particles and some evidence suggests a further reduction in CHD risk. Recent studies have shown that the combination of a fixed dose of extended-release niacin plus simvastatin reduces non-HDL-cholesterol, LDL-cholesterol, triglycerides and total cholesterol:HDL-cholesterol ratio by approximately 50% while increasing HDL-cholesterol by 25%. The safety of this combination is consistent with the safety profiles of each individual component and is well tolerated. A long-term study is currently being conducted to evaluate whether this combination therapy confers an additive impact on clinical end points.

Niacin extended-release/simvastatin

Niacin extended-release (ER)/simvastatin is a once-daily, fixed-dose combination of the HMG-CoA reductase inhibitor simvastatin and an ER formulation of niacin (a B-complex vitamin). In healthy volunteers who were given niacin ER/simvastatin 2000 mg/40 mg, niacin exposure was similar to that with niacin ER 2000 mg, while simvastatin exposure was increased compared to that with simvastatin 40 mg. In patients with elevated non-high-density lipoprotein cholesterol (non-HDL-C) but with low-density lipoprotein cholesterol (LDL-C) at or below the National Cholesterol Education Program (NCEP) goal after a > or = 2-week simvastatin 20 mg/day run-in period (SEACOAST I), 24 weeks of niacin ER/simvastatin 1000 mg/20 mg or 2000 mg/20 mg per day reduced median plasma non-HDL-C levels to a significantly greater extent than simvastatin 20 mg/day. In patients with elevated non-HDL-C and LDL-C at any level after a > or = 2-week simvastatin 40 mg/day run-in period (SEACOAST II), 24 weeks of niacin ER/simvastatin 1000 mg/40 mg or 2000 mg/40 mg per day was noninferior to simvastatin 80 mg/day in reducing median plasma non-HDL-C levels. Compared with simvastatin monotherapy, there was no significant difference in reduction in plasma LDL-C levels with niacin ER/simvastatin in SEACOAST I, and the noninferiority criterion for LDL-C was not met in SEACOAST II. However, plasma HDL-C levels increased more and triglyceride levels were lowered more than with simvastatin monotherapy (SEACOAST I and II). Niacin ER/simvastatin was generally well tolerated, with flushing being the most common adverse reaction.

Comparison of the safety and efficacy of a combination tablet of niacin extended release and simvastatin vs simvastatin monotherapy in patients with increased non-HDL cholesterol (from the SEACOAST I study)

The efficacy and safety of 2 regimens of a combination of a proprietary niacin extended release plus simvastatin (NER/S; 1,000/20 and 2,000/20 mg/day) were compared with simvastatin monotherapy (20 mg/day) for 24 weeks in 319 high-risk patients with predominantly mixed dyslipidemia who were already at National Cholesterol Education Program Adult Treatment Panel III risk-adjusted goals for low-density lipoprotein cholesterol. After a run-in on simvastatin 20 mg/day, both NER/S doses (1,000/20 and 2,000/20 mg/day) resulted in greater decreases in non-high-density lipoprotein (HDL) cholesterol vs simvastatin 20 mg/day (-13.9% and -22.5% vs -7.4%, respectively; p <0.01). Significant improvements in HDL cholesterol, triglycerides, apolipoprotein B, lipoprotein(a), and total/HDL cholesterol ratio were also observed. Patients with hypertriglyceridemia (triglycerides > or =200 mg/dl) typically had greater lipid responses to NER/S with the notable exception that HDL cholesterol responses to NER/S were similar in those with or without increased triglycerides. Treatment with both doses of NER/S was well tolerated; < or =60% of patients in any treatment group experienced flushing, >90% of flushing was mild or moderate in intensity, and only 7.5% of patients in both NER/S treatment groups discontinued because of flushing. The safety of NER/S was consistent with the safety profile of each individual component. In conclusion, this study showed that NER/S provided additional clinically relevant improvements in multiple lipid parameters and was safe and well tolerated.

Safety of niacin and simvastatin combination therapy

Niacin is the most potent lipid-altering agent for raising high-density lipoprotein (HDL) cholesterol levels. Niacin also lowers triglyceride (TG) levels, lowers low-density lipoprotein (LDL) cholesterol levels, and improves lipoprotein particle size and subclass distribution. Niacin's major adverse experience (AE) is flushing. Niacin may also increase glucose levels, liver enzymes, and uric acid levels and cause other AEs that may have clinical relevance in selected patients. Simvastatin is representative of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) class of lipid-altering drugs, which are the most effective agents for lowering LDL cholesterol levels and also have modest benefits in raising HDL cholesterol and lowering TG levels. The most common AEs with statins are muscle AEs and modest liver enzyme elevations. Because niacin and statins have complementary lipid effects and because individually, niacin and statins have been shown in outcomes studies to reduce atherosclerotic coronary artery disease events, the combined use of these 2 agents has significant potential to not only improve the lipid values of patients but improve their lives as well. Equally important is ensuring that the combination of niacin and simvastatin has an acceptable safety profile, with no greater AEs than would otherwise be expected by adding 1 agent to the other.

Niacin use and cutaneous flushing: mechanisms and strategies for prevention

Niacin, or nicotinic acid, has established efficacy for the treatment of dyslipidemia, but the clinical use of niacin has been limited by cutaneous flushing, a well-recognized associated adverse effect. Flushing has been cited as the major reason for the discontinuation of niacin therapy, estimated at rates as high as 25%-40%. A number of studies have established that moderate doses of prostaglandin inhibitors reduce the cutaneous flushing response from niacin administration. Other strategies for reducing flushing include regular consistent dosing, the use of extended-release formulations, patient education, dosing with meals or at bedtime, and the avoidance of alcohol, hot beverages, spicy foods, and hot baths or showers close to or after dosing. Because niacin has recognized cardiovascular benefits, promoting patient awareness of factors that can minimize niacin-induced flushing can help enhance the tolerability of this valuable dyslipidemic agent.