Niacin (Vitamin B 3) (Systemic)

Side Effects of This Dietary Supplement

Along with its needed effects, a dietary supplement may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your health care professional immediately if any of the following side effects occur:

With injection only

Skin rash or itching; wheezing

With prolonged use of extended-release niacin

Darkening of urine; light gray-colored stools; loss of appetite; severe stomach pain; yellow eyes or skin

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the dietary supplement. However, check with your health care professional if any of the following side effects continue or are bothersome:

Less common - with niacin only

Feeling of warmth; flushing or redness of skin, especially on face and neck; headache

With high doses

Diarrhea; dizziness or faintness; dryness of skin; fever; frequent urination; itching of skin; joint pain; muscle aching or cramping; nausea or vomiting; side, lower back, or stomach pain; swelling of feet or lower legs; unusual thirst; unusual tiredness or weakness; unusually fast, slow, or irregular heartbeat

Other side effects not listed above may also occur in some individuals. If you notice any other effects, check with your health care professional.