What the label lists and what reports show
Niacin side effects
Niacin's FDA label: “Most common adverse reactions (incidence >5% and greater than placebo) are flushing, diarrhea, nausea, vomiting, increased cough, and pruritus.” FAERS holds 11,548 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (760 reports).
- Generic listed
Check it at the source: the niacin FDA label on DailyMed (effective February 14, 2023, Aurobindo Pharma Limited); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of niacin extended-release tablets?Niacin extended-release tablets may cause serious side effects, including: unexplained muscle pain, tenderness or weakness severe liver problems. Signs of liver problems include: increased tiredness dark colored urine (tea-colored) loss of appetite light colored stools nausea right upper stomach (abdomen) pain yellowing of your skin or whites of your eye itchy skin high blood sugar level (glucose) Call your doctor right away if you have any of the side effects listed above. The most common side effects of niacin extended-release tablets include: flushing diarrhea nausea vomiting increased cough rash itching Flushing is the most common side effect of niacin extended-release tablets. Flushing happens when tiny blood vessels near the surface of the skin (especially on the face, neck, chest and/or back) open wider. […]
Source: FDA drug label, Aurobindo Pharma Limited, effective February 14, 2023 (SPL set 43233a21-3f90-4c69-bbeb-f50d5f2d35ae), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence >5% and greater than placebo) are flushing, diarrhea, nausea, vomiting, increased cough, and pruritus.
Table 2. Treatment-Emergent Adverse Reactions by Dose Level in ≥ 5% of Patients and at an Incidence Greater than Placebo; Regardless of Causality Assessment in Placebo-Controlled Clinical Trials
| Reaction | Placebo (n = 157) % | 500 mg ‡ (n = 87) % | 1,000 mg (n = 110) % | 1,500 mg (n = 136) % | 2,000 mg (n = 95) % |
|---|---|---|---|---|---|
| Diarrhea | 13 | 7 | 10 | 10 | 14 |
| Nausea | 7 | 5 | 6 | 4 | 11 |
| Vomiting | 4 | 0 | 2 | 4 | 9 |
| Cough, Increased | 6 | 3 | 2 | < 2 | 8 |
| Pruritus | 2 | 8 | 0 | 3 | 0 |
| Rash | 0 | 5 | 5 | 5 | 0 |
| Flushing & | 19 | 68 | 69 | 63 | 55 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following adverse reactions are discussed in greater detail in other sections of the labeling: Mortality and Coronary Heart Disease Morbidity [see Warnings and Precautions (5.1) ] Skeletal Muscle (rhabdomyolysis) [see Warnings and Precautions (5.2) ] Liver Dysfunction [see Warnings and Precautions (5.3) ] Laboratory Abnormalities [see Warnings and Precautions (5.4) ] Most common adverse reactions (incidence >5% and greater than placebo) are flushing, diarrhea, nausea, vomiting, increased cough, and pruritus. ( 6.1 ) Flushing of the skin may be reduced in frequency or severity by pretreatment with aspirin (up to the recommended dose of 325 mg taken 30 minutes prior to niacin extended-release tablets dose). ( 2.2 ) To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. …
Source: FDA drug label, Aurobindo Pharma Limited, effective February 14, 2023 (SPL set 43233a21-3f90-4c69-bbeb-f50d5f2d35ae), via openFDA; the full label on DailyMed
What do FAERS reports show?
11,548 reports list niacin among the medicines taken, each a report of something that happened, not proof the medicine caused it; 757 are coded as a death and 3,226 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 11 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Niacin: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions