A comparison of the efficacy and toxic effects of sustained- vs immediate-release niacin in hypercholesterolemic patients.
Level 2 - randomized trial
Double-blind randomized controlled trial comparing two active drug formulations.
What was done
A randomized, double-blind, parallel trial compared immediate-release (IR) versus sustained-release (SR) niacin in 46 hypercholesterolemic adults (23 per group) with LDL cholesterol levels exceeding 4.14 mmol/L (160 mg/dL) after 1 month of a Step 1 NCEP diet. Doses were escalated sequentially through 500, 1000, 1500, 2000, and 3000 mg/d, with each dose maintained for 6 weeks. Outcomes included fasting lipid and lipoprotein levels, clinical laboratory tests, symptom questionnaires, and withdrawal rates.
What was found
SR niacin reduced LDL cholesterol significantly more than IR niacin at doses of 1500 mg/d and above, while IR niacin increased HDL cholesterol significantly more than SR niacin at all dose levels. Triglyceride reductions were similar between groups. In the IR group, 9 of 23 patients (39%) withdrew before completing 3000 mg/d (primarily due to vasodilatory symptoms, fatigue, and acanthosis nigricans), with 0 of 23 (0%) developing hepatotoxicity. In the SR group, 18 of 23 patients (78%) withdrew before completing 3000 mg/d (primarily due to gastrointestinal symptoms, fatigue, and aminotransferase elevations), and 12 of 23 (52%) developed hepatotoxic effects.
Why it matters
This trial showed that sustained-release niacin carries a substantial risk of hepatotoxicity compared to immediate-release niacin, providing strong evidence against the unrestricted use of sustained-release formulations.
Limits
The study was small (46 participants) and conducted at a single center. The high attrition rate in both arms (especially 78% in the SR arm) limited the evaluation of the highest doses. Exact numerical lipid changes, confidence intervals, and baseline demographics were not reported in the abstract.
Cited by
- supports In published literature, liver toxicity from niacin is associated with time-released formulations rather than immediate-release free niacin.