Niacin Overdose - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Niacin toxicity is a concern right now when so many people are consuming large amounts of supplements. Niacin, also referred to as vitamin B3, is normally obtained through a balanced diet in appropriate quantities. When consumed, Niacin, in the forms of nicotinic acid and nicotinamide, undergoes metabolism primarily in the liver. Nicotinamide is currently primarily used to address nutritional niacin deficiency, while Nicotinic acid was previously utilized primarily for treating hyperlipidemia. However, with the advent of statin drugs as the main therapy, the role of Niacin in this regard has diminished, as recent trials indicate that adding Niacin to statin treatments does not provide significant improvement.

What Is Niacin Overdose?

Niacin overdose, or Niacin toxicity, occurs when an individual consumes an excessive amount of Niacin, either through their dietary intake or by taking supplements. Any surplus amounts of this water-soluble vitamin are not stored in the body and are instead eliminated through urine. However, consuming high doses of niacin can overwhelm the body's ability to excrete it, resulting in an accumulation of niacin in the bloodstream. Based on variables like one's gender, age, and general health, the ideal level of niacin in the body varies.

• Recommended daily intake of niacin for adults: Approximately 14 to 16 mg (milligram) for women and 16 to 18 mg for men.

• Tolerable upper intake level (UL) for niacin:Set at 35 mg per day for adults.

• Exceeding the daily limit of 35 mg of niacin elevates the risk of adverse effects linked to toxicity.

What Is the Pathophysiology of Niacin-Associated Hepatotoxicity?

Niacin-related liver damage (hepatotoxicity), is typically associated with ingestion of approximately three grams per day. On the other hand, the more commonly experienced symptom of flushing can occur at doses as low as 30 mg per day. Niacin undergoes liver breakdown through two distinct pathways. One pathway exhibits low binding capacity but can handle a substantial amount of nicotinic acid substrate by converting it into nicotinuric acid through conjugation with lysine. This process triggers flushing mediated by prostaglandins. The other pathway exhibits stronger binding to encountered substrates. However, it is quickly overloaded, leading to the accumulation of harmful by-products that can cause liver damage. This route is primarily involved in processing sustained-release forms of Niacin. The observed microvascular steatosis (fat accumulation) in liver damage is likely a result of mitochondrial injury, which subsequently leads to the following effects:

1. Elevation in prothrombin time.

2. Increased ammonia levels.

3. Normal bilirubin levels.

What Are the Causes of Niacin Overdose?

The common causes of Niacin overdose include:

• Excessive Intake of Niacin Supplements: Taking high doses of Niacin supplements is one of the main causes of Niacin overdose.

• Fortified Foods Products: Niacin is often added to fortified foods and beverages, such as breakfast cereals, energy drinks, and protein bars. Consuming large amounts of these products can increase the risk of Niacin overdose.

• Drug Interactions: Some medications, such as cholesterol-lowering drugs (Statins) and diabetes medications (Glitazones), can increase the risk of Niacin overdose when taken in combination with Niacin supplements.

• Inadequate Liver Function: Niacin is metabolized in the liver, and people with liver disease may have a reduced ability to metabolize Niacin, increasing the risk of toxicity.

Energy drinks often contain significant amounts of various vitamins. There have been rare instances of acute hepatitis reported, which seem to be associated with the consumption of energy drinks containing excessive levels of Niacin. Additionally, another concerning trend contributing to Niacin toxicity is the use of Niacin as a means to pass pre-employment drug tests. This practice is based on the unfounded online theory that Niacin can accelerate metabolism and aid in the elimination of toxins.

What Are the Symptoms of Niacin Overdose?

The following are the symptoms of a niacin overdose:

1. Skin flushing is the most common symptom of niacin overdose is skin flushing, which is characterized by redness, warmth, and tingling in the skin. Flushing may be accompanied by itching and burning sensations. It may manifest at doses as low as 30 mg per day. The occurrence of flushing is predominantly associated with the consumption of high-dose supplements in the form of nicotinic acid as opposed to nicotinamide.

2. Nausea, vomiting, diarrhea, and abdominal pain (epigastric pain) may occur as a result of toxicity. Epigastric pain is a discomfort or pain that is felt in the upper middle part of the abdomen.

3. Excessive niacin intake can cause a drop in blood pressure, leading to dizziness and fainting.

4. Headaches are a common symptom of niacin overdose and may be accompanied by a feeling of pressure or tightness in the head.

5. Niacin overdose can cause an increase in heart rate, which may be accompanied by palpitations and chest pain.

6. Long-term niacin overdose can cause liver damage, which may lead to yellowing of the skin and eyes (jaundice), dark urine, and abdominal swelling. Certain sustained-release formulations may have a higher incidence of hepatotoxicity. Liver damage caused by niacin is linked to a daily intake of approximately three grams.

7. Niacin can increase blood sugar levels, and taking too much niacin can lead to hyperglycemia (high blood sugar), which can cause symptoms such as excessive thirst, frequent urination, and blurred vision.

How Can Niacin Overdose Be Diagnosed?

The niacin overdose can be diagnosed in the following ways:

• Medical History: A healthcare professional will review the individual's medical history, including any medications or supplements they are taking, to determine the potential cause of niacin overdose.

• Physical Examination: A healthcare professional will examine the individual for symptoms of niacin overdose, such as skin flushing, gastrointestinal distress, dizziness, and fainting.

• Laboratory Tests: Laboratory tests can help diagnose niacin overdose and assess the severity of the condition. Niacin levels and other indicators of liver function such as alanine transaminase (ALT) and aspartate transaminase (AST) can be determined by blood testing. A urine test may also be performed to assess kidney function and detect the presence of niacin metabolites.

• Electrocardiogram (ECG): It is recommended to conduct a 12-lead electrocardiogram to detect the presence of QRS widening, QT prolongation, or any arrhythmias.

What Is the Treatment for Niacin Overdose?

The treatments options for niacin overdose include the following:

1. Discontinuing Niacin Intake: The first step in treating niacin overdose is to stop taking niacin supplements or medications.

2. Symptomatic Treatment: Healthcare professionals might suggest medicines to treat flushing, nausea, vomiting, and other symptoms, depending on the intensity of the symptoms. Intravenous fluids may be infused to avoid dehydration and preserve electrolyte balance. It may be necessary to perform re-warming in cases of hypothermia and dextrose infusion in cases of hypoglycemia. In certain instances, bicarbonate drip or vasopressor support may be required. In severe cases, the administration of fresh frozen plasma or packed red blood cells through transfusion has been necessary.

3. Blood Sugar Assessment: Individuals with niacin overdose may require frequent blood sugar monitoring to detect and manage hyperglycemia (high blood sugar).

4. Monitoring of Liver Function: Blood tests may be performed to monitor liver function and detect any liver damage.

5. Hospitalization: In severe cases of niacin overdose, hospitalization may be necessary to monitor and manage symptoms and prevent complications.

Conclusion:

Niacin overdose is a rare occurrence when taken at recommended doses, but it can occur when taken in large amounts as supplements.Avoid self-medicating with niacin supplements, especially for medical conditions such as high cholesterol and blood glucose, without first consulting with a healthcare provider. If an individual suspects that they have taken too much niacin, they should seek medical attention immediately. The prognosis for niacin overdose is generally good in most cases, provided timely diagnosis and treatment.