Niacor B3

Niacin 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)


The most common side effects of niacin include:

• flushing
• rash
• diarrhea
• nausea
• vomiting
• increased cough

Flushing is the most common side effect of niacin. Flushing happens when tiny blood vessels near the surface of the skin (especially on the face, neck, chest and/or back) open wider. Symptoms of flushing may include any or all of the following:

• warmth,
• redness,
• itching,
• tingling of the skin

Flushing does not always happen. If it does, it is usually within 2 to 4 hours after taking a dose of niacin. Flushing may last for a few hours. Flushing is more likely to happen when you first start taking niacin or when your dose of niacin is increased. Flushing may get better after several weeks.

If you wake up at night because of flushing, get up slowly, especially if you:

• feel dizzy or faint
• take blood pressure medicines

To lower your chance of flushing:

• Ask your doctor if you can take aspirin to help lower the flushing side effect from niacin. You can take aspirin (up to the recommended dose of 325 mg) about 30 minutes before you take niacin to help lower the flushing side effect.
• Do not drink hot beverages (including coffee), alcohol, or eat spicy foods around the time you take niacin.
• Take niacin with a low-fat snack to lessen upset stomach.

People with high cholesterol and heart disease are at risk for a heart attack. Symptoms of a heart attack may be different from a flushing reaction from niacin. The following may be symptoms of a heart attack due to heart disease and not a flushing reaction:

• chest pain
• pain in other areas of your upper body such as one or both arms, back, neck, jaw or stomach
• shortness of breath
• sweating
• nausea
• lightheadedness

The chest pain you have with a heart attack may feel like uncomfortable pressure, squeezing, fullness or pain that lasts more than a few minutes, or that goes away and comes back. Heart attacks may be sudden and intense, but often start slowly, with mild pain or discomfort.

Call your doctor or 911 right away if you have any symptoms of a heart attack.

Tell your doctor if you have any side effect that bothers you or does not go away.

These are not all the possible side effects of niacin. For more information, ask your doctor or pharmacist.

Do not take niacin if you have:

• liver problems
• a stomach ulcer
• bleeding problems
• an allergy to niacin or any of the ingredients in niacin.

Tell your doctor about all of your medical conditions, including if you:

• have diabetes. Tell your doctor if your blood sugar levels change after you take niacin.
• have gout
• have kidney problems
• are pregnant or plan to become pregnant. It is not known if niacin will harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant while taking niacin.
• are breastfeeding or plan to breast-feed. Niacin can pass into your breast milk. You and your doctor should decide if you will take niacin or breastfeed. You should not do both. Talk to your doctor about the best way to feed your baby if you take niacin.


Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, herbal supplements or other nutritional supplements containing niacin or nicotinamide. Niacin and other medicines may affect each other causing side effects. Niacin may affect the way other medicines work, and other medicines may affect how niacin works.

Especially tell your doctor if you take:

• other medicines to lower cholesterol or triglycerides
• aspirin
• blood pressure medicines
• blood thinner medicines
• large amounts of alcohol

Know the medicines you take. Keep a list of them to show your doctor and pharmacist when you get a new medicine.

Tell your doctor if you are breastfeeding or plan to breastfeed. Niacin is excreted into human breast milk. It is not known if niacin will harm your nursing baby.

• Take niacin exactly as your doctor tells you to take it.
• Take niacin tablets whole. Do not break, crush or chew niacin tablets before swallowing.
• Take niacin 1 time a day at bedtime after a low-fat snack. Niacin should not be taken on an empty stomach.
• All forms of niacin are not the same as niacin. Do not switch between forms of niacin without first talking to your doctor as severe liver damage can occur.
• Do not change your dose or stop taking niacin unless your doctor tells you to.
• If you need to stop taking niacin, call your doctor before you start taking niacin again. Your doctor may need to lower your dose of niacin.
• If you forget to take a dose of niacin, take it as soon as you remember.
• If you take too much niacin, call your doctor right away.
• Medicines used to lower your cholesterol called bile acid resins, such as colestipol and cholestyramine, should not be taken at the same time of day as niacin. You should take niacin and the bile acid resin medicine at least 4 to 6 hours apart.
• Your doctor may do blood tests before you start taking niacin and during your treatment. You should see your doctor regularly to check your cholesterol and triglyceride levels and to check for side effects.

If you wake up at night because of flushing, get up slowly, especially if you:

• feel dizzy or faint
• take blood pressure medicines

To lower your chance of flushing:

• Ask your doctor if you can take aspirin to help lower the flushing side effect from niacin. You can take aspirin (up to the recommended dose of 325 mg) about 30 minutes before you take niacin to help lower the flushing side effect.
• Do not drink hot beverages (including coffee), alcohol, or eat spicy foods around the time you take niacin.
• Take niacin with a low-fat snack to lessen upset stomach.

If you take too much niacin, call your local Poison Control Center or seek emergency medical attention right away.