interested in participating in a clinical trial at no charge
can find a list of open trials at<http://www.clinical
trials.gov>.Precautions
It must be emphasized that people who take high
doses of niacin to lower cholesterol and improve car-
diovascular health must treat niacin like a prescription
drug and take it only under the direction of a physi-
cian. When high doses of niacin are prescribed, the
dosage is increased gradually until the desired amount
is reached in order to reduce unpleasant of side effects.
Niacin should not be stopped suddenly without con-
sulting a physician. Individuals who take large doses
of niacin may need regular blood tests to determine the
effectiveness of the treatment.
Studies on the safety of high doses of niacin dur-
ing pregnancy have not been done. Niacin passes into
breast milk and may cause unwanted side effects in
breastfed babies. Pregnant and nursing women should
consult their physician about whether to reduce or
discontinue high-dose niacin supplements.Interactions
Niacin, especially at high doses, may interact with
other drugs. Before starting niacin supplementation,
patients should review with their physician all the pre-
scription, over-the-counter, and herbal medications that
they are taking. Some common drug interactions are:
When niacin and cholesterol-lowering statin drugs
such as lovastatin (Mevacor) or atorvastatin (Lipa-
tor) are taken together, cholesterol is lowered more
than when these drugs are taken alone.
Niacin may increase blood glucose (sugar) levels,
requiring adjustments in insulin or diabetes drugs.
Oral contraceptives may increase the amount of nia-
cin produced by the liver.
Niacin may increase the effect of nitrates (nitrogly-
cerine, isosorbide) used to treat heart conditions.Complications
When niacin is consumed within the established
DRI range, complications are rare. However, when
niacin is taken in therapeutic doses to treat disease,
serious side effects may develop. The most common
side effect is burning, tingling, or hot sensation in the
face and chest along with flushed skin. This occurs
most often at doses of 75 mg or higher. Building up
slowly to large doses of niacin may reduce the sensa-
tion, as may taking aspirin 30 minutes before taking
niacin. Other side effects include abdominal pain, diz-ziness, diarrhea, faintness, itchy skin, vomiting,
unusual thirst, and irregular heartbeat. Liver damage
may also occur at high doses.Parental concernsNiacin deficiency almost never occurs in children,
and niacin is not taken in large doses by children to
prevent disease. When taken within established DRI
ranges, parents should have few concerns about niacin.Resources
BOOKS
Berkson, Burt and Arthur J. Berkson.Basic Health Publi-
cations User’s Guide to the B-complex Vitamins.Laguna
Beach, CA: Basic Health Publications, 2006.
Gaby, Alan R., ed.A-Z Guide to Drug-Herb-Vitamin Inter-
actions Revised and Expanded 2nd Edition: Improve
Your Health and Avoid Side Effects When Using Com-
mon Medications and Natural Supplements Together.
New York: Three Rivers Press, 2006.
Lieberman, Shari and Nancy Bruning.The Real Vitamin and
Mineral Book: The Definitive Guide to Designing Your
Personal Supplement Program,4th ed. New York:
Avery, 2007.
Pressman, Alan H. and Sheila Buff.The Complete Idiot’s
Guide to Vitamins and Minerals,3rd ed. Indianapolis,
IN: Alpha Books, 2007.
Rucker, Robert B., ed.Handbook of Vitamins.Boca Raton,
FL: Taylor & Francis, 2007.
ORGANIZATIONS
American Dietetic Association. 120 South Riverside Plaza,
Suite 2000, Chicago, Illinois 60606-6995. Telephone:
(800) 877-1600. Website:<http://www.eatright.org>
American Heart Association. 7272 Greenville Avenue, Dal-
las, TX 75231. Telephone: (800) 242-8721. Website:
<http://www.americanheart.org>
Linus Pauling Institute. Oregon State University, 571
Weniger Hall, Corvallis, OR 97331-6512. Telephone:
(541) 717-5075. Fax: (541) 737-5077. Website:<http://
lpi.oregonstate.edu>
OTHER
Higdon, Jane. ‘‘Niacin.’’ Linus Pauling Institute-Oregon
State University, August 28, 2002.<http://lpi.oregon
state.edu/infocenter/vitamins/Niacin>
Harvard School of Public Health. ‘‘Vitamins.’’ Harvard
University, November 10, 2006.<http://www.hsph
.harvard.edu/nutritionsource/vitamins.html>
Maryland Medical Center Programs Center for Integrative
Medicine. ‘‘Vitamin B 3 (Niacin).’’ University of Mary-
land Medical Center, April 2002.<http://www.umm.
edu/altmed/ConsSupplements/VitaminB3Niacincs>
Mayo Clinic Staff. ‘‘Niacin-for High Cholesterol (Sys-
temic).’’ MayoClinic.com, July 4 2003.<http://
http://www.mayoclinic.com/health/drug-information/
DR202404>Niacin