NIACOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NIACOR (NIACOR).
Niacin (nicotinic acid) reduces VLDL and LDL synthesis by inhibiting lipolysis in adipose tissue, decreasing free fatty acid flux to the liver, and inhibiting hepatic triglyceride synthesis. It also increases HDL by reducing catabolism of apolipoprotein A-I.
| Metabolism | Hepatic metabolism via two pathways: conjugation with glycine to form nicotinuric acid (major, low-affinity high-capacity) and oxidation to N-methylnicotinamide and other metabolites (minor, high-affinity low-capacity). Enzymes involved: nicotinamide N-methyltransferase (NNMT) and aldehyde oxidase. |
| Excretion | Renal: 60-88% as unchanged drug and metabolites after oral administration; fecal: <2% |
| Half-life | 20–45 minutes for immediate-release niacin; terminal half-life of main metabolites (nicotinuric acid) is approximately 1.5–4 hours; short half-life necessitates multiple daily dosing for lipid effects |
| Protein binding | <20% bound to albumin; minimal binding to other plasma proteins |
| Volume of Distribution | 0.5–0.7 L/kg; indicates distribution into total body water and some tissue binding |
| Bioavailability | Oral immediate-release: 60–76% (variable due to first-pass metabolism); sustained-release: lower bioavailability (50–60%) due to increased presystemic metabolism |
| Onset of Action | Oral: 15–30 minutes for vasodilation/flushing; lipid-lowering effects require several days to weeks of chronic dosing |
| Duration of Action | Immediate-release: flushing lasts 0.5–2 hours; lipid effects persist with continued dosing; sustained-release formulations extend duration to 8–12 hours |
Initial: 250 mg orally once daily after evening meal; titrate up by 250–500 mg/day every 2–4 weeks. Maintenance: 1–2 g/day in divided doses (2–3 times daily). Maximum: 6 g/day.
| Dosage form | TABLET |
| Renal impairment | No specific adjustment recommended; use caution in severe renal impairment (CrCl <30 mL/min) due to potential accumulation; consider reducing dose or prolonging interval. |
| Liver impairment | Contraindicated in Child-Pugh class B and C; use with caution in mild impairment (Child-Pugh A) with dose reduction of 50% initially. |
| Pediatric use | For hyperlipidemia (off-label): Initial 50–100 mg/kg/day orally divided into 2–3 doses; titrate over 4–6 weeks up to 200–300 mg/kg/day; maximum 6 g/day. Not recommended in children <2 years. |
| Geriatric use | Start at lowest dose (250 mg daily); titrate slowly due to increased risk of flushing, hypotension, and hepatotoxicity; monitor liver function and glucose closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NIACOR (NIACOR).
| Breastfeeding | Niacin is excreted into human breast milk in minimal amounts; M/P ratio unknown. The American Academy of Pediatrics considers niacin compatible with breastfeeding. However, high maternal doses may lead to adverse effects in the infant due to potential accumulation. Caution is advised; monitor infant for flushing or gastrointestinal disturbances. |
| Teratogenic Risk | FDA Pregnancy Category C. Niacin is not recommended for use in pregnant women due to potential fetal harm, though no well-controlled studies exist. In animal studies, high doses have caused fetal abnormalities. First trimester: Avoid use due to theoretical risk of teratogenicity. Second and third trimesters: Use only if clearly needed, as niacin can cause vasodilation and potential hypotension, which may reduce uteroplacental perfusion. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to niacin or any component of formulation","Significant or unexplained hepatic dysfunction","Active peptic ulcer disease","Arterial hemorrhage"]
| Precautions | ["Hepatotoxicity: elevated liver enzymes, hepatitis; discontinue if persistent elevations occur","Flushing: prostaglandin-mediated, can be reduced by taking aspirin prior; tolerance develops","Hyperuricemia: may precipitate gout","Hyperglycemia: may increase blood glucose; use with caution in diabetes","Peptic ulcer disease: reactivation may occur","Hypotension: can occur, especially with vasoactive drugs"] |
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| Fetal Monitoring | Monitor maternal liver function tests (LFTs), serum glucose, uric acid, and lipid profile regularly. In pregnancy, monitor for signs of hepatotoxicity, hyperglycemia, and hypotension. Fetal monitoring includes assessment of growth and well-being via ultrasound and non-stress tests if prolonged use occurs. |
| Fertility Effects | No known adverse effects on fertility in humans. Animal studies have not shown impaired fertility at therapeutic doses. However, extreme hypertriglyceridemia (an indication for niacin) may be associated with infertility, which improves with treatment. |