Niacin sustained-release

Several different niacin formulations are available niacin immediate-release (IR), niacin sustained-release (SR), and niacin extended-release (ER).28,29 These formulations differ in terms of dissolution and absorption rates, metabolism, efficacy, and side effects. Limitations of niacin IR and SR are flushing and hepatotoxicity, respectively. These differences appear related to the dissolution and absorption rates of niacin formulations and its subsequent metabolism. Niacin IR is available by prescription (Niacor ) as well as a dietary supplement which is not regulated by the FDA.28 Currently, there are no FDA-approved niacin SR products, thus, all SR products are available only as dietary supplements. 

Niacin 50 to 750 mg tabs or caps, i m med i ate- re I ease 250 to 750 mg sustained-release 1 -5 g/day in three or more divided doses 1-2 g/day (never exceed 2 g/day due to increased risk of hepatotoxicity) hyperuricemia. 

Potentially important laboratory abnormalities occurring with niacin therapy include elevated liver function tests, hyperuricemia, and hyperglycemia. Niacin-associated hepatitis is more common with sustained-release preparations, and their use should be restricted to patients intolerant of regular-release products. Niacin is contraindicated in patients with active liver disease, and it may exacerbate preexisting gout and diabetes. 

Sustained-release niacin (not the same as extended-release product) Should be avoided ... 

Knopp RH. Clinical profiles of plain versus sustained-release niacin (Niaspan) and the physiologic rationale for nighttime dosing. Am J Cardiol 1998 82(12A) 24U-28U ... 

Henkin Y, Johnson KC, Segrest JP. Rechallenge with crystalline niacin after drug-induced hepatitis from sustained-release niacin. JAMA 1990 264(2) 241-3. 

Keenan JM, Fontaine PL, Wenz JB, Myers S, Huang ZQ, Ripsin CM. Niacin revisited. A randomized, controlled trial of wax-matrix sustained-release niacin in hypercholesterolemia. Arch Intern Med 1991 151(7) 1424-32. 

Sources Shrimpton, 1997 institute of Medicine, 1997, 1998, 2000, 2001 Scientific Committee for Food, 1993 where two figures are shown for vitamin A, the lower is for women and the higher is for men (Tabie 2.5). for niacin and nicotinic acid, the lower values are for sustained release preparations theEU upper level of 25 mg of vitamin Be was proposed by the Scientific Committee for Food Opinion, 2000 and the EU upper level of 200 [jug of vitamin B12 was set because of the possible presence of inactive corrinoids in pharmaceutical preparations, not because of toxicity of the vitamin itself. 

A prescription-only sustained-release niacin, NiaSpan, has been widely promoted to doctors, but the formulation, frankly, is inferior to that of Endur-acin. Readers of mine whose doctors convinced them to switch from Endur-acin to NiaSpan have written to me complaining of flushing and gastric disturbances. 

Niacin TLDL and VLDL Synthesis 4-Triglyceride and cholesterol 4VLDL, 4LDL, fHDL Problems with patient acceptance good in combination with bile acid resins extended-release niacin causes less flushing and is less hepatotoxic than sustained-release niacin... 

In low HDL, the primary target remains LDL according to the ATP III, but emphasis shifts to weight reduction, increased physical activity, and smoking cessation and, if drug therapy is required, to fibric acid derivatives and niacin. Niacin has the potential for the greatest increase in HDL, and the effect is more pronounced with regular or immediate-release forms than with sustained-release forms. ... 

Niacin is indicated for hypertriglyceridemia and elevated LDL-C it is especially useful in patients with both hypertriglyceridemia and low HDL-C levels. There are two commonly available forms of niacin. Crystalline niacin (immediate-release or regular) refers to niacin tablets that dissolve quickly after ingestion. Sustained-release niacin refers to preparations that continuously release niacin for 6 to 8 hours after ingestion. Niaspan is the only preparation of niacin that has been approved by the FDA for treating dyslipidemia and that requires a prescription. 

Over-the-connter, snstained-release niacin preparations and Niaspan are effective up to a total daily dose of 2 g per day. All doses of sustained-release niacin, but particularly doses above 2 g per day, have been reported to cause hepatotoxicity, which may occur soon after beginning therapy or after several years of nse. The potential for severe liver damage shonld preclnde its nse in most patients, inclnding those who have taken an eqnivalent dose of crystalline niacin safely for many years and are considering switching to a sustained-release preparation. Niaspan may be less likely to cause hepatotoxicity. 

The most common serious side effects are hepatotoxicity, manifested as elevated serum transaminases and hyperglycemia Both regular (crystalline) niacin and sustained-release niacin have been reported to cause severe liver toxicity, and sustained-release niacin can cause fulminant hepatic failure. An extended-release niacin (NIASPAN), appears to be less likely to cause severe hepatotoxicity, perhaps because it is administered only once daily. The incidence of flushing and pruritus with this preparation is not substantially different from that with regular niacin. Severe hepatotoxicity is more likely to occur when patients take >2 g of sustained-release, over-the-counter preparations. Affected patients experience flu-like fatigue and weakness. Usually, serum transaminases are elevated serum albumin levels decline, and total cholesterol and LDL-C levels decline substantially. 

F. Acute ingestion of niacin but not niacinamide (nicotinamide) may produce unpleasant dramatic cutaneous flushing and pruritus, which may last for a few hours. Chronic excessive use (particularly the sustained-release form) has been associated with hepatitis. 

Fischer, D.J., Knight, L.L., and Vestal, R.E., 1991. Fulminant hepatic failure following low-dose sustained-release niacin therapy in hospital. The Western Journal of Medicine. 155 410-412. 

High intakes of both nicotinic acid and nicotinamide, in excess of 500 mg/day, also cause liver damage, and prolonged use can result in liver failure. This is especially a problem with sustained release preparations of niacin, which permit a high blood level to be maintained for a relatively long time. 

McKenney JM, Proctor JD, Harris S, Chinchili VM. A comparison of the efficacy and toxic effects of sustained-vs immediate-release niacin in hypercholesterolemic patients. JAMA 1994 271(9) 672-7. 

McKenney, J. M., Proctor, ]., Harris, S and Chinchili, V. (1994). A comparison of the efficacy and toKic effects of sustained- vs. immediate-release niacin in hypcrcholcstcrolemic patients, AMA 271, 672-677. 

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