Is Niacinamide (Nicotinamide) Safe with Niacin high dose?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid adding niacinamide supplements when prescribed high-dose niacin therapy. Monitor liver function tests regularly. Report signs of hepatotoxicity: nausea, vomiting, jaundice, right upper quadrant pain. Total niacin equivalents should be clinically tracked.
Why this interaction occurs
Both nicotinic acid (niacin) and niacinamide are forms of Vitamin B3 metabolized hepatically. Combined high doses exceed the liver's metabolic capacity, increasing risk of hepatocellular injury, cholestatic hepatitis, and in severe cases fulminant hepatic failure.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 2,519,437 reports mentioning Niacin high dose. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Niacin high dose + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.