Pharmacology · Class
Nicotinic acid and derivatives !
Niacin (vitamin B3) at lipid-lowering doses: it lowers triglycerides and LDL and raises HDL, but flushing limits its use and it is now rarely chosen.
Updated 2026-11-01
What they are
Nicotinic acid (niacin) and related compounds such as acipimox. At doses far above vitamin needs they act as lipid-modifying drugs.
Mechanism of action
Niacin activates a Gi-coupled receptor (GPR109A, also called HCA2) on adipocytes, lowering cAMP and hormone-sensitive lipase activity, so fewer free fatty acids reach the liver. In the liver it reduces triglyceride synthesis, increases apo B degradation and lowers VLDL and LDL output; it also raises HDL. The same receptor on skin immune cells releases prostaglandins, which cause flushing.
Target: Niacin receptor HCA2 (GPR109A), a Gi-coupled receptor
Drugs in this class
Others in the class
- acipimox
- nicotinamide (vitamin B3, no lipid effect)
Test yourself
Think of the answer, then tap the question to see it.
What causes niacin flushing and how is it reduced?
Prostaglandin release in the skin through the niacin receptor; aspirin before the dose reduces it, as does slow dose escalation.
Which two metabolic laboratory values rise on niacin?
Glucose (insulin resistance) and uric acid (gout risk).
Which niacin switch carries a risk of severe liver toxicity?
Replacing immediate-release niacin with a sustained-release product at the same dose.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - NIACIN tablet, extended release (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 37 (McGraw Hill, 2023); Cryo-EM structure of niacin bound human hydroxy-carboxylic acid receptor 2 (Local refinement) (RCSB Protein Data Bank, 2023).
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Representative model, for educational purposes only.