NIASPAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NIASPAN (NIASPAN).
Niacin (nicotinic acid) reduces hepatic production of VLDL and LDL, and increases HDL by inhibiting diacylglycerol acyltransferase-2 (DGAT2) and reducing hepatic triglyceride synthesis. It also decreases the catabolism of HDL apolipoproteins A-I and A-II.
| Metabolism | Primarily hepatic metabolism via two pathways: conjugation with glycine to form nicotinuric acid (major pathway, saturable) and conversion to nicotinamide adenine dinucleotide (NAD). Minor metabolism via oxidation to N-methylnicotinamide and other metabolites. |
| Excretion | Primarily renal (60-76% as unchanged drug and metabolites). Hepatic metabolism is extensive; less than 2% excreted in feces. |
| Half-life | Terminal half-life is 20-45 minutes (immediate-release) but due to prolonged release formulation of Niaspan, the half-life is extended to 2-4 hours for total nicotinic acid and 12 hours for nicotinuric acid, allowing once-daily dosing. |
| Protein binding | <20% bound to plasma proteins (mainly albumin). Binding is negligible at therapeutic concentrations. |
| Volume of Distribution | Approximately 0.5 L/kg (around 35 L in a 70 kg adult), indicating distribution into total body water. |
| Bioavailability | Oral (extended-release): ~60-76% due to extensive first-pass metabolism. Bioavailability is dose-dependent and saturable at higher doses. |
| Onset of Action | Oral (extended-release): Onset of lipid-lowering effects occurs within days, with maximal reduction in triglycerides and LDL-C seen at 4-8 weeks. Flushing occurs within 30-60 minutes after dose. |
| Duration of Action | Lipid-lowering effects persist for 24 hours with once-daily dosing due to extended-release formulation. Flushing lasts 30-60 minutes but tolerance develops over weeks. |
Starting dose: 500 mg orally once daily at bedtime; after 4 weeks, increase to 1000 mg once daily; then titrate to maintenance dose of 1500-2000 mg once daily; maximum dose: 2000 mg/day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | No specific dose adjustment provided by manufacturer; use with caution in patients with renal impairment; avoid in patients with severe renal impairment or nephrotic syndrome. |
| Liver impairment | Contraindicated in patients with significant or unexplained hepatic dysfunction; use with caution in patients with Child-Pugh class A, avoid in Child-Pugh class B or C. |
| Pediatric use | Safety and efficacy not established in pediatric patients; not recommended for use. |
| Geriatric use | No specific dose adjustment recommended; monitor for adverse effects such as myopathy and hepatotoxicity; initiate at low end of dosing range. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NIASPAN (NIASPAN).
| Breastfeeding | Niacin is excreted in human breast milk in amounts that are likely comparable to maternal plasma levels. The milk-to-plasma (M/P) ratio for niacin is approximately 1.0. The American Academy of Pediatrics considers niacin compatible with breastfeeding at usual dietary intakes, but high pharmacological doses should be avoided due to potential adverse effects in the infant, such as flushing and gastrointestinal disturbances. |
| Teratogenic Risk | Niacin (NIASPAN) is classified as FDA Pregnancy Category C. Animal studies have shown adverse effects at high doses, but there are no adequate and well-controlled studies in pregnant women. Niacin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There is no evidence of teratogenicity in humans at recommended doses, but high doses may cause fetal harm. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Active liver disease or unexplained transaminase elevations","Active peptic ulcer disease","Arterial bleeding","Hypersensitivity to niacin or any component of the formulation"]
| Precautions | ["Hepatotoxicity: elevated liver enzymes, rare severe hepatotoxicity; avoid in patients with active liver disease","Flushing: prostaglandin-mediated, can be reduced by taking aspirin or starting with low doses","Hyperglycemia: may increase blood glucose, use with caution in diabetic patients","Hyperuricemia: may precipitate gout, monitor uric acid","Gastrointestinal effects: can cause peptic ulcer, use caution with history of GI bleeding","Cardiovascular: may cause hypotension, especially with concurrent use of antihypertensives"] |
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| Fetal Monitoring | Monitor liver function tests (LFTs) before initiation and periodically during therapy due to risk of hepatotoxicity. Check fasting lipid profile, blood glucose, and uric acid levels. Monitor for symptoms of flushing, pruritus, and gastrointestinal intolerance. Fetal monitoring is not specifically required but consider periodic fetal assessments if prolonged therapy is necessary. |
| Fertility Effects | There are no known adverse effects of niacin on fertility in humans. Animal studies have not shown impaired fertility at clinically relevant doses. Niacin is not known to affect reproductive function in either males or females. |