Niacinamide Ingredients & Drug Interactions
by GNC Mega Men
What is this page for?
First and foremost: checking Niacinamide against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.
Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy
Niacinamide is a dietary supplement by GNC Mega Men with 1 active ingredient. Its ingredients are commonly taken for high cholesterol, vitamin b3 deficiency (pellagra), heart health support.Based on those ingredients, 727 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Niacin. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Niacinamide by GNC Mega Men
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AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of Niacinamide by GNC Mega Men
Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.
What’s inside
Full disclosure
GNC Mega Men's Niacinamide contains one active ingredient: niacin. Niacin is a B vitamin that supports energy metabolism and has been used at high doses to help manage cholesterol and other lipid problems.
The tablet also contains inactive ingredients — dicalcium phosphate, cellulose, and whole brown rice — that serve as fillers and binders.
Does it work?
Strong evidence
Niacin is likely effective for pellagra, a rare vitamin deficiency disease. It's possibly effective for managing abnormal cholesterol and lipids linked to HIV/AIDS, and possibly effective for metabolic syndrome.
The evidence we hold doesn't establish whether this dose in GNC Mega Men is potent enough for those conditions — that depends on how much niacin is in each tablet and how it's formulated, and we don't have that detail.
How safe is it?
Well-documented data
Niacin from food and standard amounts in supplements is generally well tolerated. At higher supplemental doses, the most common side effects are flushing (affecting up to 70% of people at therapeutic doses), stomach upset (nausea, vomiting, heartburn, abdominal pain, diarrhea, constipation), and elevated liver enzymes.
Rare serious effects include liver damage, muscle breakdown, blood clotting problems, and vision changes — especially with sustained-release formulations and long-term high-dose use. During pregnancy, the niacin in food and standard prenatal vitamins is safe, but high-dose niacin should be avoided unless prescribed by your doctor.
During breastfeeding, normal dietary niacin is fine, but again, high-dose supplements should only be used if directed. If you're pregnant, planning to be, or breastfeeding, talk with your doctor or pharmacist before taking a supplement dose.
Meds to double-check
Moderate interaction found
Before you take this niacinamide supplement, check with your doctor or pharmacist if you're on blood thinners or antiplatelet drugs, diabetes medications, blood-pressure drugs, liver-damaging medications, statins (cholesterol drugs), or gout medications like allopurinol or probenecid. If you take a bile acid sequestrant (cholestyramine or colestipol), separate your doses by 4 to 6 hours.
These are the main medication types that interact with niacin.
The bottom line
Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.
This product is a straightforward niacin supplement — useful if you need a B-vitamin boost, but it interacts with several important medication types, especially blood thinners, diabetes drugs, and blood-pressure medications. If you take any prescription drugs or have liver disease, gout, or diabetes, run this past your doctor or pharmacist before you start.
It's also worth checking whether the dose here gives you the niacin you're after and whether it's safe for your particular situation.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Dec 23, 2011.
This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed
General information
Key facts about Niacinamide, straight from the product label.
| Brand | GNC Mega Men |
|---|---|
| Net contents | 30 Pack(s) |
| Market status | On market |
| Date entered into DSLD | Dec 23, 2011 |
| DSLD ID | 3558 |
| Product type | Vitamin |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult Male (18-50 Years) |
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.
Supplement Facts
The label details for Niacinamide by GNC Mega Men, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Niacin | 100 mg | 500% |
Other ingredients: Dicalcium Phosphate, Cellulose, Whole Brown Rice
Tap any ingredient to jump to its full detail below.
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
General Statements
- Niacinamide - Provides dietary support for a healthy blood lipid profile and plays an important function in energy metabolism.*
ACTUAL SIZE
Niacinamide
Potencies verified by GNC procedure #5103. Conforms to USP <2091> for weight. Meets USP <2040> disintegration.
Each pack contains:
CLINICALLY STUDIED
GNC QUALITY COMMITMENT GNC, the leader in the development and manufacture of dietary supplements, is committed to producing the highest quality products available. This commitment begins with quality designed supplement formulations. Every raw material that goes into a GNC supplement is guaranteed as to quality and potency. Each product is dated and then shipped immediately to our stores, so you can be sure you are purchasing the freshest supplements available. At GNC, we extend our quality commitment to your by offering our money-back guarantee. GNC GUARANTEE Use any GNC supplement for as little as 10 days. If you are not 100% completely satisfied, return the unused portion of the product with proof of purchase to your GNC store for a complete refund of your purchase price. No questions asked!
Precautions
WARNING: Niacin may cause a tempory flushing reaction. Consult your physician prior to using this product if you are pregnant, nursing, taking medication, or have a medical condition.
KEEP OUT OF REACH OF CHILDREN.
Formulation
No Artificial Colors, No Wheat, No Gluten, No Dairy, Yeast Free.
General
CODE 328611 CMG
Storage
Store in a cool, dry place.
FDA Disclaimer Statement
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
FDA Statement of Identity
Dietary Supplement
Suggested/Recommended/Usage/Directions
DIRECTIONS: As a dietary supplement, take the contents of one pack daily with food.
Brand IP Statement(s)
Dr. Frank J. Costa, M.D., an internationally acclaimed urological sugeon and men's health expert, is part of the GNC Medical Advisory Board. One of "America's Top Physcicians," Dr. Costa lectures nationally and internationally on men's health topics. Dr. Costa is regularly featured in television, radio and newspaper interviews and has published articles in both professional journals and popular magazines. "If heart health is a concern, I recommend the Mega Men(r) Heart Vitapak(r) Program. It's the first of its kind to include both a premium men's multivitamin and balanced heart support, with ingredients shown to lower cholesterol and support healthy blood pressure."
VITAPAK(R) PROGRAM FOR COMPLETE CARDIO PROTECTION - Clinically studied multivitamin^ with 1,600 IU of vitamin D-3 - Lowers LDL (bad) cholesterol with phytosterols~ - Helps maintain normal, healthy blood pressure levels* - Supports blood vessel function and healthy lipid profile with CoQ-10 and niacin*
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Niacinamide by GNC Mega Men label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.
View the full label (PDF)The Ingredients in Niacinamide by GNC Mega Men
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.
Niacin
Interacts with727 drugs
Niacin (vitamin B3) is an essential nutrient your body needs for energy and metabolism, and deficiency is uncommon in most developed countries. Prescr...
Niacin monograph & interactionsOther (inactive) ingredients: Dicalcium Phosphate, Cellulose, Whole Brown Rice. These complete the product’s ingredient list but are not active constituents.
Niacinamide by GNC Mega Men Drug Interactions
HelloPharmacist Interaction Report
GNC Mega Men's Niacinamide (niacin) does interact with medications through eight drug categories.
The most serious concern is with blood thinners and antiplatelet drugs (anticoagulants/antiplatelets) — niacin may add to their effects, and sustained-release niacin has been linked to blood clotting problems in rare cases.
Read the full breakdown — every affected drug type, severity by severity
Niacin can raise blood sugar and may weaken diabetes medications, lower blood pressure and amplify antihypertensive drugs, and theoretically increase the risk of liver damage when combined with hepatotoxic drugs. It may also raise the risk of muscle breakdown (myopathy) and severe muscle injury (rhabdomyolysis) if you're taking statins, though this risk hasn't been proven in large clinical trials.
Additionally, niacin can interfere with gout medications — both allopurinol and probenecid — by reducing uric acid excretion.
Niacin is also bound by bile acid sequestrants (cholestyramine, colestipol), which can cut its absorption sharply; if you take either of those, space this supplement 4 to 6 hours apart from them. Altogether, these interactions span 728 individual medications.
None of the inactive ingredients we have data for show documented interactions. Check your exact medications with the search tool on this page before you start.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Niacinamide?
Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.
Go to the checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in Niacinamide interact with 727 drugs. Click any drug to see the details.
1 of the 1 ingredient in Niacinamide interact with drugs. Each result below shows which ingredient is responsible. Niacin
Amiloride, HydrochlorothiazideAmil-Co, Amilzide, Moduret 25, Moduretic
How Amiloride, Hydrochlorothiazide interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amiloride, Hydrochlorothiazide interactionAminosalicylic AcidPaser
How Aminosalicylic Acid interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Aminosalicylic Acid interactionAmiodaroneCordarone, Pacerone
How Amiodarone interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amiodarone interactionAmlodipineNorliqva
How Amlodipine interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine interactionAmlodipine BenzoateKaterzia
How Amlodipine Benzoate interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine Benzoate interactionAmlodipine BesilateIstin
How Amlodipine Besilate interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine Besilate interactionAmlodipine BesylateNorvasc
How Amlodipine Besylate interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine Besylate interactionAmlodipine Besylate, BenazeprilLotrel
How Amlodipine Besylate, Benazepril interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine Besylate, Benazepril interactionAmlodipine, CelecoxibConsensi
How Amlodipine, Celecoxib interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Amlodipine, Celecoxib interactionAmmonium ChlorideAmmonium Chloride
How Ammonium Chloride interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntihypertensive Drugs Moderate
Interaction Summary
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full Niacin + Ammonium Chloride interactionAmoxicillinAmix, Amoram, Amoxident, Amoxil Capsules, Amoxil Injection, Galenamox +3 more
How Amoxicillin interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amoxicillin interactionAmoxicillin VeterinaryBiomox
How Amoxicillin Veterinary interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amoxicillin Veterinary interactionAmoxicillin, Clavulanate PotassiumAugmentin, Augmentin '125/31 SF', Augmentin '250/62 SF', Augmentin XR, Augmentin-Duo 400/57, Clavulin
How Amoxicillin, Clavulanate Potassium interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amoxicillin, Clavulanate Potassium interactionAmoxicillin, Omeprazole Magnesium, RifabutinTalicia
How Amoxicillin, Omeprazole Magnesium, Rifabutin interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amoxicillin, Omeprazole Magnesium, Rifabutin interactionAmphotericin, TetracyclineMysteclin-F
How Amphotericin, Tetracycline interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Amphotericin, Tetracycline interactionAnacaulase-bcdbNexoBrid
How Anacaulase-bcdb interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Anacaulase-bcdb interactionAnagrelideAgrylin
How Anagrelide interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Anagrelide interactionAnidulafunginEraxis
How Anidulafungin interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Anidulafungin interactionAnisindioneMiradon
How Anisindione interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Anisindione interactionAntidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) InhibitorGlyxambi
How Antidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) Inhibitor interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAntidiabetes Drugs Moderate
Interaction Summary
Niacin can increase blood glucose levels and may diminish the effects of antidiabetes drugs.
Read the full Niacin + Antidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) Inhibitor interactionAntithrombin IiiThrombate III
How Antithrombin Iii interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Antithrombin Iii interactionApixabanEliquis
How Apixaban interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Apixaban interactionAprocitentanTryvio
How Aprocitentan interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs, Antihypertensive Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Aprocitentan interactionArgatrobanArgatroban
How Argatroban interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Argatroban interactionAsparaginase Erwinia Chrysanthemi (recombinant)-rywnRylaze
How Asparaginase Erwinia Chrysanthemi (recombinant)-rywn interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinHepatotoxic Drugs Moderate
Interaction Summary
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Read the full Niacin + Asparaginase Erwinia Chrysanthemi (recombinant)-rywn interactionAspirinAngettes 75, ASA, Asaphen, Aspirin, Caprin, Cartia +8 more
How Aspirin interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs, Aspirin Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Aspirin interactionAspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #3
How Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAspirin, Anticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Large doses of aspirin might alter the clearance of niacin.
Read the full Niacin + Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interactionAspirin, ButalbitalAxotal
How Aspirin, Butalbital interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs, Aspirin Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Aspirin, Butalbital interactionAspirin, Butalbital, CaffeineFiorinal
How Aspirin, Butalbital, Caffeine interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAspirin, Anticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Large doses of aspirin might alter the clearance of niacin.
Read the full Niacin + Aspirin, Butalbital, Caffeine interactionAspirin, Butalbital, Caffeine, Codeine PhosphateFiorinal w/ Codeine
How Aspirin, Butalbital, Caffeine, Codeine Phosphate interacts with Niacinamide — through 1 ingredient. Tap an ingredient for the detail:
NiacinAnticoagulant/antiplatelet Drugs, Aspirin Moderate
Interaction Summary
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Read the full Niacin + Aspirin, Butalbital, Caffeine, Codeine Phosphate interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Niacinamide with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.
Niacin
Alcohol (Ethanol)
Concomitant use of alcohol and niacin might increase the risk of flushing and hepatotoxicity.
Alcohol can exacerbate the flushing and pruritus associated with niacin. Large doses of niacin might also exacerbate liver dysfunction associated with chronic alcohol use. A case report describes delirium and lactic acidosis in a patient taking niacin 3 grams daily who ingested 1 liter of wine. Advise patients to avoid large amounts of alcohol while taking niacin.
Allopurinol (Zyloprim)
Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as allopurinol.
Large doses of niacin can reduce urinary excretion of uric acid, potentially resulting in hyperuricemia. Doses of uricosurics such as allopurinol might need to be increased to maintain control of gout in patients who start taking niacin. People who have frequent attacks of gout despite uricosuric therapy should avoid niacin.
Anticoagulant/Antiplatelet Drugs
Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.
Several cases of clotting factor synthesis deficiency and coagulopathy have been reported in patients taking sustained-release niacin. Also, thrombocytopenia has been reported in patients treated with niacin or niacin plus lovastatin.
Antidiabetes Drugs
Niacin can increase blood glucose levels and may diminish the effects of antidiabetes drugs.
Niacin impairs glucose tolerance in a dose-dependent manner, probably by causing or aggravating insulin resistance and increasing hepatic production of glucose. In diabetes patients, niacin 4.5 grams daily for 5 weeks can increase plasma glucose by an average of 16% and glycated hemoglobin (HbA1c) by 21%. However, lower doses of 1.5 grams daily or less appear to have minimal effects on blood glucose. In some patients, glucose levels increase when niacin is started, but then return to baseline when a stable dose is reached. Up to 35% of patients with diabetes may need adjustments in hypoglycemic therapy when niacin is added.
Antihypertensive Drugs
Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
The vasodilating effects of niacin can cause hypotension. Furthermore, some clinical evidence suggests that a one-hour infusion of niacin can reduce systolic, diastolic, and mean blood pressure in hypertensive patients. This effect is not observed in normotensive patients.
Bile Acid Sequestrants
Bile acid sequestrants can bind niacin and decrease absorption. Separate administration by 4-6 hours to avoid an interaction.
In vitro studies show that colestipol (Colestid) binds about 98% of available niacin and cholestyramine (Questran) binds 10% to 30%.
Gemfibrozil (Lopid)
Theoretically, concomitant use of niacin and gemfibrozil might increase the risk of myopathy in some patients.
A case of myopathy from concomitant use of niacin and gemfibrozil has been reported. Niacin alone has also been associated with cases of myopathy. Using gemfibrozil with niacin might further increase the risk of developing myopathy.
Hepatotoxic Drugs
Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.
Niacin has been associated with cases of liver toxicity, especially when used in pharmacologic doses. Sustained-release niacin preparations appear to be associated with a higher risk of hepatotoxicity than immediate-release niacin.
Hmg-Coa Reductase Inhibitors ("Statins")
Theoretically, concomitant use of niacin and statins might increase the risk of myopathy and rhabdomyolysis in some patients.
Some case reports have raised concerns that niacin might increase the risk of myopathy and rhabdomyolysis when combined with statins. However, a significantly increased risk of myopathy has not been demonstrated in clinical trials, including those using an FDA-approved combination of lovastatin and niacin (Advicor).
Probenecid (Benemid)
Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as probenecid.
Large doses of niacin reduce urinary excretion of uric acid, potentially causing hyperuricemia. Doses of uricosurics such as probenecid might need to be increased to maintain control of gout in patients who start taking niacin. People who have frequent attacks of gout despite uricosuric therapy should avoid niacin.
Sulfinpyrazone (Anturane)
Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as sulfinpyrazone.
Large doses of niacin reduce urinary excretion of uric acid, potentially causing hyperuricemia. Doses of uricosurics such as sulfinpyrazone might need to be increased to maintain control of gout in patients who start taking niacin. People who have frequent attacks of gout despite uricosuric therapy should avoid niacin.
Thyroid Hormone
Theoretically, niacin might antagonize the therapeutic effects of thyroid hormones.
Clinical research and case reports suggests that taking niacin can reduce serum levels of thyroxine-binding globulin by up to 25% and moderately reduce levels of thyroxine (T4). Patients taking thyroid hormone for hypothyroidism might need dose adjustments when using niacin.
Transdermal Nicotine (Nicoderm)
Theoretically, concomitant use of niacin and transdermal nicotine might increase the risk of flushing and dizziness.
Niacin and nicotine can both cause flushing and dizziness.
Warfarin (Coumadin)
There is limited evidence that niacin may increase the anticoagulant effects of warfarin.
In a case report, a patient on warfarin developed an elevated international normalized ratio (INR) of 3.9 after taking niacin for two weeks. The patient's INR was previously stable, ranging between 2 and 3 in recent months, and no other medication changes were identified. The elevated INR returned to therapeutic range within 4 days following the discontinuation of niacin.
Aspirin
Large doses of aspirin might alter the clearance of niacin.
Aspirin is often used with niacin to reduce niacin-induced flushing. Doses of 80-975 mg aspirin have been used, but 325 mg appears to be optimal. Aspirin also seems to reduce the clearance of niacin by competing for glycine conjugation. Taking aspirin 1 gram seems to reduce niacin clearance by 45%. This is probably a dose-related effect and not clinically significant with the more common aspirin dose of 325 mg.
Brand information
Manufacturer and brand details for Niacinamide, from the product label.
Niacinamide by GNC Mega Men: Common Questions
Does Niacinamide by GNC Mega Men interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
What's niacinamide, and how is it different from niacin?
Will niacinamide cause flushing?
Is it safe to take this while pregnant?
Can niacin affect my blood sugar?
What are the most serious side effects?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Niacinamide is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.
The Full Monographs Behind Niacinamide’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
Niacinamide's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
The 66 references behind this product’s interaction data
Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.
Niacin 66 references
- Garg R, Malinow MR, Pettinger M, et al. Niacin treatment increases plasma homocysteine levels. Am Heart J 1999;138:1082-7.
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