Niacin, also called nicotinic acid, is a B vitamin (vitamin B3). It occurs naturally in plants and animals, and is also added to many foods as a vitamin supplement. Niacin is also present in many multiple vitamins and nutritional supplements.

Niacin is used to treat and prevent a lack of natural niacin in the body, and to lower cholesterol and triglycerides (types of fat) in the blood. It is also used to lower the risk of heart attack in people with high cholesterol who have already had a heart attack. Niacin is sometimes used to treat coronary artery disease (also called atherosclerosis).

Niacin may also be used for purposes other than those listed in this medication guide.

Do not take this medication if you are allergic to niacin, or if you have severe liver disease, a stomach ulcer, or active bleeding.

Niacin can cause certain side effects, such as flushing (warmth, itching, redness, or tingly feeling under your skin). These effects can be made worse if you drink alcohol or hot beverages shortly after you take niacin. These effects should disappear over time as you keep taking the medication.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

Avoid taking colestipol (Colestid) or cholestyramine (Locholest, Prevalite, Questran) at the same time you take niacin. If you take either of these other medications, take them at least 4 to 6 hours before or after you take niacin.

Niacin is only part of a complete program of treatment that may also include diet, exercise, weight control, and other medications. Follow your diet, medication, and exercise routines very closely.

Do not take this medication if you are allergic to niacin, or if you have severe liver disease, a stomach ulcer, or active bleeding.

Before taking niacin, tell your doctor if you are allergic to any drugs, or if you have:

• liver or kidney disease;

• heart disease or uncontrolled angina (chest pain);

• a stomach ulcer;

• diabetes;

• gout; or

• a muscle disorder such as myasthenia gravis.

If you have any of these conditions, you may not be able to use niacin, or you may need dosage adjustments or special tests during treatment.

FDA pregnancy category C. Niacin may be harmful to an unborn baby when the medication is taken at doses to treat high cholesterol or other conditions. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Niacin can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.