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    Thomas Behrenbeck, M.D.

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Question

Niacin overdose: What are the symptoms?

I take niacin to treat my high cholesterol, but I've heard that if you take too much it can be harmful. Should I be concerned?

Answer

from Thomas Behrenbeck, M.D.

Niacin overdose is unlikely if you take niacin only in the amount prescribed by your doctor. In recommended doses, niacin is an effective treatment for high cholesterol, high blood fats (lipids) and niacin deficiency.

You may have heard that too much niacin can be harmful because of Internet rumors. The rumors falsely state that by taking a large amount of niacin, people can flush the chemicals that show they've used marijuana out of their bodies before they take a drug test. No studies have shown that niacin can do this, and this can be very dangerous because it may lead to niacin overdose.

Signs and symptoms of a niacin overdose include:

  • Rapid heartbeat
  • Skin flushing combined with dizziness
  • Itching
  • Nausea and vomiting
  • Abdominal pain
  • Diarrhea
  • Severe liver damage (hepatoxicity)

If you're concerned about a potential niacin overdose, talk to your doctor to make sure you're taking the correct amount. If you think you may have overdosed, seek medical attention immediately.

Next question
Coenzyme Q10: Can it prevent statin side effects?
References
  1. Guyton JR, et al. Safety considerations with niacin therapy. American Journal of Cardiology. 2007;6:S22.
  2. Mittal MK, et al. Toxicity from the use of niacin to beat urine drug screening. Annals of Emergency Medicine. 2007;50:587.

AN01644

July 11, 2009

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