Pharmacology Update

Niaspan: A New Long-Acting Niacin

By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD

The food and drug administration has granted approval to Kos Pharmaceuticals, Inc. to market Niaspan, a new long-acting niacin preparation. Niacin is an effective antilipemic that not only lowers LDL-C but raises HDL-C and lowers triglycerides. Kos has used a hydrogel extended-release tablet delivery system that is designed to be taken at bedtime. Slow-release niacin products are associated with fewer bothersome side effects common with immediate-release niacin, such as flushing, but concern about liver toxicity has limited their use.

Indications

Niaspan is indicated as an adjunct to diet for reduction of elevated total cholesterol, LDL-cholesterol, Apo B, and triglycerides levels in adults with primary hypercholesterolemia and mixed dyslipidemia (Type IIa and IIIb); as combination therapy with bile acid binding resins for reduction of elevated total and LDL-cholesterol in adults with primary hypercholesterolemia; treatment of adults with very high triglyceride levels at risk of pancreatitis; to reduce the risk of recurrent nonfatal myocardial infarction in hypercholesterolemic patients; and to slow progression or promote regression of atherosclerosis in combination with a bile acid binding resin in patients with a history of coronary artery disease and hypercholesterolemia.1

Potential Advantages

Niaspan is dosed once daily allowing better compliance and causing fewer flushing episodes. In a comparative study with intermediate niacin, following four weeks of maintenance therapy at daily doses of 1500 mg, the incidence of flushing averaged 8.56 events per patient for intermediate niacin compared to 1.88 following Niaspan. In placebo-controlled trials (n = 245), less than 6% of patients discontinue therapy due to flushing.1

Potential Disadvantages

Flushing is still the most common side effect of Niaspan. Flushing episodes were reported by up to 88% of the patients.1 A statistically significant elevation in aspartate aminotransferase has been reported, although the mean values remained within normal limits.2 It has been suggested that controlled-release formulations of niacin may be more hepatotoxic than immediate-release formulations.3,4 The long-term safety of Niaspan has not been established. The manufacturer warns that Niaspan not be substituted for equivalent doses of immediate-release niacin.1

Dosing Information

Niaspan is available in 350 mg, 500 mg, 750 mg, and 1000 mg tablets. Therapy should be initiated with 375 mg at bedtime, after a low-fat snack. After one week, the dose is increased to 500 mg for one week then 750 mg for one week.

The dose is increased to 1000 mg (2 ´ 500 mg) on week four. If this dose is inadequate after week 7, the dose should be titrated to response or tolerance. The recommended maintenance dose is 1000-2000 mg per day. Taking an NSAID 30 minutes before Niaspan and avoiding hot drinks or alcohol around the time of Niaspan may help to minimize flushing.1 Niaspan is available as a 21-day starter pack to facilitate titration during the first three weeks.

Comments

Niacin has long been established as an effective antilipidemic agent. It decreases total cholesterol, LDL-cholesterol, liproprotein(a), and triglycerides and elevates HDL-cholesterol. In clinical studies, it has been shown to decrease mortality and the incidence of recurrent nonfatal myocardial infarctions.5 In combination with bile acid-binding drugs (i.e., colestipol, cholestyramine), niacin has been shown to slow or promote progression of atherosclerotic plaques.6 Niaspan has been reported to have a similar effect on the lipid profile as other niacin products. A dose of 1500 mg/d of Niaspan reduced total cholesterol by 20%, LDL-cholesterol by 12%, liproprotein(a) by 15%, and triglycerides by 15%, while HDL-cholesterol was elevated by 20%.1 It appears to be more effective in elevating HDL-cholesterol than in lowering LDL-cholesterol. This profile more closely mimics the effects of immediate-release niacin than some sustained-release products.7,8 Side effects, particularly flushing, have limited the broad use of niacin as a first-line agent. Various controlled-release formulations have been marketed to improve tolerance. Niaspan offers an FDA-approved once-daily form. As with all niacin products, patient selection and monitoring are essential.

Niaspan is priced at $0.75 to $1.22 per day (1000-2000 mg) It is less expensive than the statins but more expensive than generic gemfibrozil.

Clinical Implications

Niaspan offers an effective, well-tolerated form of niacin, the tried and true anti-lipemic that improves all lipid fractions. Although long-term safety of the drug is not yet established, Niaspan offers clinicians an alternative in the battle against cardiovascular disease.

References

1. Niaspan Product Information. Kos Pharmaceuticals, Inc. August 1997.

2. Morgan JM, et al. J Cardiovasc Pharmacol Therapeut 1996;1:196-202.

3. McKenney JM, et al. JAMA 1994;271:672-677.

4. Rader JI, et al. Am J Med 1992;92:77-81.

5. Canner PL, et al. J Am Coll Cardiol 1986;8:1245-1255.

6. Blankenhorn DH, et al. JAMA 1987;257:3233-3240.

7. Schectman G, et al. Ann Intern Med 1996;125: 990-1000.

8. Gray DR, et al. Ann Intern Med 1994;121:252-258.