Contrasting effects of unmodified and time-release forms of niacin on lipoproteins in hyperlipidemic subjects: clues to mechanism of action of niacin.
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.(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003692:Delayed-Action Preparations; D004041:Dietary Fats / Q000378:metabolism; D005260:Female; D005483:Flushing / Q000139:chemically induced; D006801:Humans; D006949:Hyperlipidemias / Q000378:metabolism*; D008074:Lipoproteins / Q000097:blood / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D009525:Niacin / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D010349:Patient Compliance; D011897:Random Allocation; D014280:Triglycerides / Q000097:blood
D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D003692:Delayed-Action Preparations; D004041:Dietary Fats; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D014280:Triglycerides; D009525:Niacin