|
Efficacy and safety of an extended-release niacin (Niaspan): a long-term study
Crystalline nicotinic acid (immediate-release niacin) is effective therapy for lipoprotein regulation and cardiovascular risk reduction. However, inconvenient regimens and unpleasant side effects decrease compliance. Sustained-release formulations designed to circumvent these difficulties increase hepatotoxicity. Niaspan, a new US Food and Drug Administration (FDA)-approved, once-daily, extended-release form, has been found effective and safe in short-term trials. The long-term efficacy and safety of Niaspan lipid monotherapy was studied in 517 patients (aged 21-75 years) for < or =96 weeks in dosages < or =3,000 mg/day. Primary efficacy endpoints were low-density lipoprotein (LDL) cholesterol and apolipoprotein B (apo B) changes from baseline; secondary efficacy endpoints were changes in total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, lipoprotein(a), and total cholesterol/HDL-cholesterol ratio; safety data included adverse events and laboratory values over the 2-year study period. LDL-cholesterol levels decreased significantly: 18% at week 48 and 20% at week 96; apo B reduction was similar (16% decrease at week 48 and 19% at week 96). Large elevations in HDL cholesterol (26%, week 48; 28%, week 96) allowed only modest decreases in total cholesterol (12% and 13%, respectively), whereas total cholesterol/HDL-cholesterol ratio decreased by almost one third. Triglyceride and lipoprotein(a) levels were decreased by 27% and 30%, respectively (week 48), and by 28% and 40%, respectively (week 96). All changes from baseline were significant (p <0.001). Niaspan was generally well tolerated, although flushing was common (75%); however, there was a progressive decrease in flushing with time from 3.3 episodes in the first month to < or = 1 episode by week 48. Aspirin was used by one third of patients before Niaspan dosing to minimize flushing episodes. Although serious adverse events occurred in about 10% of patients, none were considered probably or definitely related to Niaspan. Adverse events in general varied widely, but their true relation to the study drug is difficult to ascertain without a placebo (control) group. No deaths occurred. There were statistically significant changes in hepatic transaminases, alkaline phosphatase, direct bilirubin, phosphorus, glucose, amylase, and uric acid. However, these changes were mostly small and are not likely to be biologically or clinically significant (the decrease in phosphorus is a new finding in niacin therapy). No myopathy was observed. Thus, this long-term study confirms the earlier short-term findings that Niaspan is safe and effective as monotherapy in plasma lipoprotein regulation.
|
A new extended-release niacin (Niaspan): efficacy, tolerability, and safety in hypercholesterolemic patients
Immediate-release niacin manifests beneficial effects in cardiovascular disease with respect to dyslipidemic states. It lowers low-density lipoprotein (LDL) cholesterol, triglycerides, lipoprotein(a), and apoprotein B; at the same time, it increases high-density lipoprotein (HDL) cholesterol, HDL2, and apoprotein A-I. However, use of crystalline niacin has drawbacks: therapy requires multidose regimens, and side effects include flushing and pruritus. Slowing absorption with sustained-release formulations succeeds in decreasing flushing and increasing tolerance, but increases in hepatic enzyme levels have raised safety concerns. A new extended-release, once-daily formulation of niacin (Niaspan) shows promise in minimizing flushing while avoiding hepatotoxicity. A multicenter, randomized, double-blind clinical trial of Niaspan enrolled 122 patients with confirmed diagnosis of primary dyslipidemia (LDL cholesterol >4.14 mmol/L [160 mg/dL] and triglycerides <9 mmol/L [800 mg/dL]) into 3 treatment groups: (1) Niaspan 1,000 mg/day; (2) Niaspan 2,000 mg/day; and (3) placebo. The primary treatment endpoint was LDL-cholesterol level. This endpoint was not significantly affected by placebo (0.2% increase), but Niaspan decreased LDL cholesterol by 5.8% (1,000 mg/day) and 14.6% (2,000 mg/day) (p <0.001). Likewise, with placebo there were significant changes in total cholesterol, triglycerides, lipoprotein(a), and apoprotein B, whereas both Niaspan 1,000 and 2,000 mg/day significantly (p <0.001) decreased these parameters. In addition, both Niaspan groups showed significant (p <0.001) increases in HDL cholesterol (17% and 23%, respectively), including HDL subfractions. With respect to flushing, 20% of the placebo group reported at least 1 episode, whereas 88% and 83% of the Niaspon 1,000- and 2,000-mg/day groups, respectively, reported episodes. There was no hepatotoxicity as liver enzyme levels remained within clinically accepted limits in all treatment groups. However, Niaspan 2,000 mg/day showed a significant increase in aspartate aminotransferase compared with baseline and placebo. This trial demonstrated a cholesterol-modifying effect of Niaspan consistent with those reported for niacin, but demonstrated a better tolerance for flushing. Moreover, in contrast to sustained-release formulations, Niaspan showed relatively mild hepatic effects.
|
Clinical trial experience with extended-release niacin (Niaspan): dose-escalation study
Niacin is a useful lipid-modifying drug because it (1) decreases low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, and lipoprotein(a), and (2) raises high-density lipoprotein (HDL) cholesterol. Its use tends to be limited by side effects and inconvenient dosing regimens. The availability of an extended-release preparation (Niaspan-which has safety and efficacy similar to immediate-release niacin but which can be given once a day) provides an opportunity to increase the use of this effective lipid-modifying agent. To study the safety and efficacy of escalating doses of extended-release niacin, hyperlipidemic patients were randomly assigned to placebo or Niaspan. A forced dose-titration was done with the dosage increasing by 500 mg every 4 weeks to a maximum of 3,000 mg/day. Niaspan showed dose-related changes in total, LDL, and HDL cholesterol levels, triglycerides, cholesterol/HDL ratio, and lipoprotein(a). At a dosage of 2,000 mg/day, total cholesterol decreased by 12.1%, LDL cholesterol by 16.7%, triglycerides by 34.5%, and lipoprotein(a) by 23.6%; HDL cholesterol increased by 25.8%. Flushing was the most commonly reported side effect; flushing episodes tended to decrease with time despite an increasing dose of niacin. Of the reported side effects, only pruritus and rash were significantly different between the 2 groups. Aspartate aminotransferase, lactate dehydrogenase, and uric acid increased in a dose-dependent fashion, but fasting blood sugar increased by about 5% across most dosages. Two subjects had aspartate aminotransferase levels greater than twice the upper limit of normal, but there were no subjects in whom transaminases increased to 3 times the upper limit of normal. Women tended to have a greater LDL cholesterol response to the medication and also experienced more side effects, especially at higher dosages. Thus, the use of lower dosages of niacin may be desirable in women. The results of this dose-escalation study show beneficial effects of Niaspan on the entire lipid profile. At the maximum recommended dosage of 2,000 mg/day, all lipid and lipoprotein levels changed in desirable directions. Side effects (other than flushing) and blood chemistries were comparable to those seen with immediate-release niacin.
|
|
|
|
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.
|
Extended-release niacin for modifying the lipoprotein profile
Niacin (nicotinic acid) favourably modifies all aspects of the lipoprotein profile; it raises high-density lipoprotein cholesterol (HDL-C) levels, lowers triglyceride, low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a) levels and reduces atherogenic small, dense LDL particles. One large monotherapy trial and multiple trials of niacin in combination with other lipid-modifying drugs show remarkable consistency in the ability of niacin to improve angiographic and clinical outcomes. In practice, however, the use of regular, immediate-release niacin (niacin IR) has been limited by the side effect of flushing. Sustained-release (SR) formulations, developed in order to reduce flushing, were found to cause serious hepatotoxicity at varying frequencies. Extended-release niacin (niacin ER; Niaspan), Kos Pharmaceuticals, Inc.) is a prescription formulation of niacin, administered once-daily at bedtime. Niacin ER is as effective in modifying lipoprotein levels as an equal daily dose of niacin IR and it causes less flushing. In addition, niacin ER administered once-daily is not associated with the increased hepatotoxicity reported with SR formulations. Niacin ER has been studied extensively in combination therapy with statins, including lovastatin in a recently introduced combination tablet. Myopathy has not been a substantial problem in statin/niacin ER combination therapy. Finally, a study of niacin ER given to diabetic patients showed only mild trends towards increased glycosylated haemoglobin concentrations and a need for additional antidiabetic medication. Thus, niacin ER represents an effective and safe option in the management of low levels of HDL-C and other lipoprotein abnormalities in a variety of settings.
|
|
|
