Some commonly used brand names are:

In the U.S.—

In Canada—

Other commonly used names are: Nicotinamide Nicotinic acid Vitamin B 3

• Nutritional supplement, vitamin

Vitamins (VYE-ta-mins) are compounds that you must have for growth and health. They are needed in small amounts only and are usually available in the foods that you eat. Niacin and niacinamide are necessary for many normal functions of the body, including normal tissue metabolism. They may have other effects as well.

Lack of niacin may lead to a condition called pellagra. Pellagra causes diarrhea, stomach problems, skin problems, sores in the mouth, anemia (weak blood), and mental problems. Your health care professional may treat this by prescribing niacin for you.

Some conditions may increase your need for niacin. These include:

• Cancer
• Diabetes mellitus (sugar diabetes)
• Diarrhea (prolonged)
• Fever (prolonged)
• Hartnup disease
• Infection (prolonged)
• Intestinal problems
• Liver disease
• Mouth or throat sores
• Overactive thyroid
• Pancreas disease
• Stomach ulcer
• Stress (prolonged)
• Surgical removal of stomach

Increased need for niacin should be determined by your health care professional.

Claims that niacin is effective for treatment of acne, alcoholism, unwanted effects of drug abuse, leprosy, motion sickness, muscle problems, poor circulation, and mental problems, and for prevention of heart attacks, have not been proven. Many of these treatments involve large and expensive amounts of vitamins.

Injectable niacin and niacinamide are given by or under the supervision of a health care professional. Other forms of niacin and niacinamide are available without a prescription.

Niacin and niacinamide are available in the following dosage forms:

Oral
• Niacin
  • Extended-release capsules (U.S.)
  • Solution (U.S.)
  • Tablets (U.S. and Canada)
  • Extended-release tablets (U.S. and Canada)
• Niacinamide
  • Tablets (U.S. and Canada)

Parenteral
• Niacin
  • Injection (U.S.)
• Niacinamide
  • Injection (U.S.)

Vitamins alone will not take the place of a good diet and will not provide energy. Your body also needs other substances found in food such as protein, minerals, carbohydrates, and fat. Vitamins themselves often cannot work without the presence of other foods.

The daily amount of niacin needed is defined in several different ways.

For U.S.—
• Recommended Dietary Allowances (RDAs) are the amount of vitamins and minerals needed to provide for adequate nutrition in most healthy persons. RDAs for a given nutrient may vary depending on a person's age, sex, and physical condition (e.g., pregnancy).
• Daily Values (DVs) are used on food and dietary supplement labels to indicate the percent of the recommended daily amount of each nutrient that a serving provides. DV replaces the previous designation of United States Recommended Daily Allowances (USRDAs).

For Canada—
• Recommended Nutrient Intakes (RNIs) are used to determine the amounts of vitamins, minerals, and protein needed to provide adequate nutrition and lessen the risk of chronic disease.

Normal daily recommended intakes in milligrams (mg) for niacin are generally defined as follows:

If you are taking this dietary supplement without a prescription, carefully read and follow any precautions on the label. For niacin or niacinamide, the following should be considered:

Allergies—Tell your health care professional if you have ever had any unusual or allergic reaction to niacin or niacinamide. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—It is especially important that you are receiving enough vitamins when you become pregnant and that you continue to receive the right amount of vitamins throughout your pregnancy. The healthy growth and development of the fetus depend on a steady supply of nutrients from the mother. However, taking large amounts of a dietary supplement in pregnancy may be harmful to the mother and/or fetus and should be avoided.

Breast-feeding—It is especially important that you receive the right amounts of vitamins so that your baby will also get the vitamins needed to grow properly. However, taking large amounts of a dietary supplement while breast-feeding may be harmful to the mother and/or baby and should be avoided.

Children—Problems in children have not been reported with intake of normal daily recommended amounts.

Older adults—Problems in older adults have not been reported with intake of normal daily recommended amounts.

Other medicines—Medicines or other dietary supplements

Although certain medicines or dietary supplements should not be used together at all, in other cases they may be used together even if an interaction might occur. In these cases, your health care professional may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are using any other dietary supplement or any prescription or nonprescription (over-the-counter [OTC]) medicine.

• Bleeding problems or
• Diabetes mellitus (sugar diabetes) or
• Glaucoma or
• Gout or
• Liver disease or
• Low blood pressure or
• Stomach ulcer—Niacin or niacinamide may make these conditions worse

Dosing—

The amount of niacin and niacinamide needed to meet normal daily recommended intakes will be different for different individuals. The following information includes only the average amounts of niacin and niacinamide.

For niacin
• For oral dosage form (capsules, extended-release capsules and tablets, tablets, oral solution):
  • To prevent deficiency, the amount taken by mouth is based on normal daily recommended intakes:
    For the U.S.
    • Adult and teenage males—15 to 20 milligrams (mg) per day.
    • Adult and teenage females—13 to 15 mg per day.
    • Pregnant females—17 mg per day.
    • Breast-feeding females—20 mg per day.
    • Children 7 to 10 years of age—13 mg per day.
    • Children 4 to 6 years of age—12 mg per day.
    • Children birth to 3 years of age—5 to 9 mg per day.
    For Canada
    • Adult and teenage males—14 to 23 mg per day.
    • Adult and teenage females—14 to 16 mg per day.
    • Pregnant females—14 to 16 mg per day.
    • Breast-feeding females—14 to 16 mg per day.
    • Children 7 to 10 years of age—14 to 18 mg per day.
    • Children 4 to 6 years of age—13 mg per day.
    • Children birth to 3 years of age—4 to 9 mg per day.
  • To treat deficiency:
    • Adults, teenagers, and children—Treatment dose is determined by prescriber for each individual based on the severity of deficiency.

For niacinamide
• For oral dosage form (tablets):
  • To prevent deficiency, the amount taken by mouth is based on normal daily recommended intakes:
    For the U.S.
    • Adult and teenage males—15 to 20 milligrams (mg) per day.
    • Adult and teenage females—13 to 15 mg per day.
    • Pregnant females—17 mg per day.
    • Breast-feeding females—20 mg per day.
    • Children 7 to 10 years of age—13 mg per day.
    • Children 4 to 6 years of age—12 mg per day.
    • Children birth to 3 years of age—5 to 9 mg per day.
    For Canada
    • Adult and teenage males—14 to 23 mg per day.
    • Adult and teenage females—14 to 16 mg per day.
    • Pregnant females—14 to 16 mg per day.
    • Breast-feeding females—14 to 16 mg per day.
    • Children 7 to 10 years of age—14 to 18 mg per day.
    • Children 4 to 6 years of age—13 mg per day.
    • Children birth to 3 years of age—4 to 9 mg per day.
  • To treat deficiency:
    • Adults, teenagers, and children—Treatment dose is determined by prescriber for each individual based on the severity of deficiency.

If this dietary supplement upsets your stomach, it may be taken with meals or milk. If stomach upset (nausea or diarrhea) continues, check with your health care professional.

For individuals taking the extended-release capsule form of this dietary supplement:

• Swallow the capsule whole. Do not crush, break, or chew before swallowing. However, if the capsule is too large to swallow, you may mix the contents of the capsule with jam or jelly and swallow without chewing.

For individuals taking the extended-release tablet form of this dietary supplement:

• Swallow the tablet whole. If the tablet is scored, it may be broken, but not crushed or chewed, before being swallowed.

Missed dose—

If you miss taking a vitamin for one or more days there is no cause for concern, since it takes some time for your body to become seriously low in vitamins. However, if your health care professional has recommended that you take this vitamin, try to remember to take it as directed every day.

Storage—

To store this dietary supplement:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the dietary supplement to break down.
• Keep the liquid form of this dietary supplement from freezing.
• Do not keep outdated dietary supplements or those no longer needed. Be sure that any discarded dietary supplement is out of the reach of children.

This dietary supplement may cause you to feel dizzy or faint, especially when you get up from a lying or sitting position. Getting up slowly may help. This effect should lessen after a week or two as your body gets used to the dietary supplement. However, if the problem continues or gets worse, check with your health care professional.

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.