How to Spot Signs of Niacin Overdose

Medically reviewed by Jennifer Boidy, RN

Last Updated: June 30, 2022 References

Whether it is happening to you or someone else, a nutritional overdose can be scary. Niacin, more commonly referred to as vitamin B3, which is in various food sources, such as fish, poultry, milk, lean meats, eggs, and legumes.^{[1]
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MedlinePlus
Collection of medical information sourced from the US National Library of Medicine
Go to source} Most people get enough niacin through their diet and it is essentially impossible to overdose on niacin from diet alone. Doctors may prescribe niacin supplements for dyslipidemia (abnormal cholesterol levels). Niacin may also be helpful for atherosclerosis, hypertension, arthritis and other conditions, but the research on niacin's benefit for these conditions is limited. A high dosage of niacin can be toxic and result in an overdose. To spot the signs of niacin overdose, you should be able to recognize both visible and internal symptoms. If an overdose is suspected, should seek medical attention immediately.

Method 1

Method 1 of 3:

Recognizing Visible Symptoms

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Look for severe flushing of the skin along with dizziness. One of the most common side effects of taking niacin is flushed skin, but it may not indicate an overdose. However, severe flushing along with dizziness is a symptom of an overdose.^{[2]
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PubMed Central
Journal archive from the U.S. National Institutes of Health
Go to source} Flushing can include redness, warm, itchy or irritated skin, as well as a tingly feeling under the skin. These symptoms can be enhanced if alcoholic or hot beverages are taken shortly after the niacin.^{[3]
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- If you frequently get flushed from taking niacin, then look into getting a time released version of your niacin supplement.
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Watch for signs of nausea and vomiting. A niacin overdose can cause symptoms associated with nausea and an upset stomach. For example, you may experience vomiting and diarrhea.^{[4]
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Identify any abdominal pain. Pain in your abdomen may also indicate a niacin overdose. Pay attention to how your stomach feels and note if there is any pain.^{[5]
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Mayo Clinic
Educational website from one of the world's leading hospitals
Go to source} Make sure to tell your doctor about this symptom.
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Note any itching. If your skin is itchy, then this may also be a sign of a niacin overdose. You may notice an itchy feeling in one localized area of your body or all over.^{[6]
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Check for signs of gout. Gout is another symptom of niacin overdose. ^{[7]
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Research source} You may notice pain, swelling, or a purplish color in the area around a joint, such as the joint in your big toe. You may also notice that you cannot move the joint as easily as you normally do. As your gout improves, you may experience some peeling and itching in the skin around the joint.^{[8]
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Notice signs of jaundice. Niacin is processed by the liver, and as a result, an overdose may cause liver damage and cause the development of jaundice like symptoms. This includes yellowing of the skin and eyes.^{[9]
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Method 2

Method 2 of 3:

Noticing Internal Signs of Overdose

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Monitor your heart rate. In cases when a niacin overdose has taken place, you may experience a fast, pounding, uneven, or irregular heartbeat.^{[10]
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Research source} If you have a cardiovascular condition, such as coronary artery disease (CAD), then you are at a higher risk of developing this symptom and should have your heart rate closely monitored by your physician.
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Look for signs of low blood pressure. If you already have low blood pressure or you are on a blood pressure medication, then you are at a higher risk of developing dangerously low blood pressure. If an overdose occurs your blood pressure may decrease to dangerous levels. Symptoms associated with severely low blood pressure include, fatigue, dizziness, blurred vision, and the feeling that you may pass out.^{[11]
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Research source} Some of the other signs of severely low blood pressure from a niacin overdose include nausea, rapid and shallow breathing, and an inability to concentrate.^{[12]
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American Heart Association
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Go to source}
- You should never take niacin if you already have low blood pressure.
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Visit your doctor regularly. While taking niacin supplements, you should have your blood tested regularly by your doctor. This way your doctor can monitor your overall health, particularly the functioning of your liver and kidneys. Kidney or liver failure can be severe and even deadly, if left untreated.^{[13]
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Method 3

Method 3 of 3:

Treating a Niacin Overdose

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Seek medical attention immediately. If you believe that you, or someone you know, has overdosed on niacin, you should seek medical attention immediately. Go to your nearest hospital emergency room or call for emergency services, such as by dialing 911 in the US. Some side effects of a niacin overdose are severe and can lead to other life-threatening conditions including kidney, liver, or heart failure.^{[14]
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Treat the symptoms that occur. A niacin overdose can impact your liver, blood pressure, and heart rate. It is likely that your physician will take supportive measures to treat the medical conditions that are presenting.^{[15]
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Research source} For example, you may receive supportive measures, such as IV hydration (due to vomiting and diarrhea), oxygen therapy, emergency medications to bring your blood pressure up, and/or life support (if needed).^{[16]
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Research source} You may also be required to have your blood tested to see if your liver is functioning properly.^{[17]
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- Keep in mind that hepato-toxicity (liver damage) is a risk when you are taking high doses of niacin or when you are taking the extended release version of niacin.^{[18]
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Stop taking niacin. Most of the side effects related to a niacin overdose will subside once you stop taking niacin. Your doctor will likely terminate your use of the drug. Niacin can then be re-prescribed at a lower daily dosage.^{[19]
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Warnings

Keep in mind that niacin can interact with many other medications. Make sure to tell your doctor about any medications or supplements you are taking.

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Niacin may irritate your stomach, so make sure to take it with meals.

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Always follow the dosage prescribed by your doctor and only take niacin under the direction of a doctor. You will also need to attend all follow-up appointments and go for lab testing to monitor niacin's effects on you. Overdosing on niacin can lead to severe side effects that require medical attention.^{[21]
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If you have a history of liver disease, certain cardiovascular diseases, kidney disease, stomach ulcers, gout, or low blood pressure, you should not take niacin.

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A high dose of niacin will not flush drugs out of your system, and can lead to an overdose. Do not take niacin in high doses! You should not take niacin as a way to pass drug screening tests.^{[22]
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Keep in mind that slow release versions of niacin may reduce side effects but increase your risk of liver toxicity.^{[23]
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