Contrasting effects of unmodified and time-release forms of niacin on lipoproteins in hyperlipidemic subjects: clues to mechanism of action of niacin

• Published in: Metabolism, clinical and experimental Vol. 34; no. 7; p. 642
• Main Authors: Knopp, R.H, Ginsberg, J, Albers, J.J, Hoff, C, Ogilvie, J.T, Warnick, G.R, Burrows, E, Retzlaff, B, Poole, M
• Format: Journal Article
• Language: English
• Published: United States 01.07.1985
• Subjects: Adult; Apolipoprotein A-I; Apolipoprotein A-II; Apolipoproteins A - blood; Cholesterol, HDL - blood; Cholesterol, LDL - blood; Delayed-Action Preparations; Dietary Fats - metabolism; Female; Flushing - chemically induced; Humans; HYPERLIPEMIA; Hyperlipidemias - metabolism; LIPOPROTEINAS; LIPOPROTEINE; LIPOPROTEINS; Lipoproteins - blood; Lipoproteins - metabolism; Lipoproteins, HDL - blood; Male; METABOLISM; METABOLISME; METABOLISMO; Middle Aged; Niacin - administration & dosage; Niacin - adverse effects; Niacin - therapeutic use; NICOTINAMIDA; NICOTINAMIDE; Patient Compliance; Random Allocation; Triglycerides - blood
• ISSN: 0026-0495; 1532-8600
• DOI: 10.1016/0026-0495(85)90092-7

To minimize the cutaneous flushing symptoms associated with niacin use, a time-release capsule form of niacin has been formulated. Thus study compares the effects of time-release niacin with those of unmodified niacin on lipoprotein lipids, including HDL2 and HDL3, apoproteins A-I and A-II, clinical chemistries, symptomatic side effects, and adherence to the medication regimen. Seventy-one primarily hypercholesterolemic subjects were randomized to either unmodified niacin or time-release niacin ad took medication for a six-month period. The two groups were closely matched on anthropomorphic and lipid variables. Adherence to the therapeutic regimen at a dose of 1.5 g/d in the first month of treatment was similar in the two groups. Thereafter, at a dose of 3.0 g/d, adherence was in excess of 90% among subjects taking unmodified niacin but only 64% among those taking time-release niacin, chiefly because of aggravated gastrointestinal symptoms; cutaneous flushing side effects, however, were slightly less common with time-release niacin. At these levels of adherence, LDL cholesterol (C) was reduced 21% by unmodified niacin and 13% by the time release form. Plasma total triglyceride was reduced more with unmodified niacin (27%) than with time-release niacin (8% maximum), and HDL-C and HDL2-C were increased significantly with unmodified niacin (26% and 36%) and were not significantly changed by time-release niacin. Increased to a similar degree on both regimens were HDL3-C (approximately 35%) and apoA-I (approximately 12%). ApoA-II was not affected by either drug regimen.