Drug & supplement interaction

Niacinamide + Carbamazepine

Carbamazepine brand names: Tegretol, Tegretol XR, Equetro, Carbatrol, Carnexiv.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Niacinamide has a moderate interaction with Carbamazepine. Niacinamide might increase the levels and adverse effects of carbamazepine.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Niacinamide and Carbamazepine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CARBAMAZEPINE (Tegretol)

Niacinamide might increase the levels and adverse effects of carbamazepine.
Plasma levels of carbamazepine were increased in two children given high-dose niacinamide, 60-80 mg/kg/day. This might be due to inhibition of the cytochrome P450 enzymes involved in carbamazepine metabolism. There is not enough data to determine the clinical significance of this interaction.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist: your body relies on liver enzymes (the CYP450 family) to break down carbamazepine and keep its level in a safe range. In a couple of children taking very high doses of niacinamide (about 60 to 80 mg per kilogram a day), carbamazepine levels rose. The thinking is that big amounts of niacinamide may slow those enzymes, so the drug clears more slowly and can build up.

Carbamazepine is a narrow-margin medicine, so even modest rises can bring on dizziness, drowsiness, blurred or double vision, unsteadiness, or nausea. That said, this is based only on a couple of case reports, so it's far from certain. Everyday vitamin amounts and skin-care products are very unlikely to matter. Before starting a high-dose niacinamide supplement, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bourgeois BF, Dodson WE, Ferrendelli JA. Interactions between primidone, carbamazepine, and nicotinamide. Neurology 1982;32:1122-6.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Niacinamide Also Interacts With Other Medications

Niacinamide has 123 moderate known drug interactions in our database — the Carbamazepine one above is one of them. If you take anything else, check it against the full list below.

Moderate 123 No known interaction 2,707 (incl. Carbamazepine)
Taking anything else?

Check Another of Your Medications Against Niacinamide

Covers the 2,830 medications we’ve checked against Niacinamide. Pick one to open its full report.

From our Q&A

Questions About Niacinamide or Carbamazepine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Niacinamide or Carbamazepine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Carbamazepine

This page covers Niacinamide only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Carbamazepine page lists 284 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Gamma-hydroxybutyrate (ghb) (major).

By severity: 12 major · 235 moderate · 37 minor.

From our pharmacist’s overview on the Carbamazepine page

“Carbamazepine (Tegretol, Carbatrol, Equetro) only controls seizures and mood episodes when its blood level stays inside a tight window, and 284 supplement and herbal ingredients on file can disturb that balance, 12 of them rated major. Grapefruit can push carbamazepine levels up, St.”

Reviewed by 2 · Jul 18, 2026

Open the Carbamazepine interaction page

One more smart check

Taking Niacinamide as Part of a Dietary Supplement Product? Check It for Interactions

We hold 552 real supplement products containing Niacinamide, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Niacinamide. Your product may carry other ingredients that interact with Carbamazepine too, on top of Niacinamide — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Niacinamide and Carbamazepine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Niacinamide
Top 25%

#305 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Carbamazepine
Top 25%

#401 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Niacinamide

What is Niacinamide?

  • Acne and skin health
  • Pellagra (niacin deficiency)
  • Anti-aging and skin tone
  • Rosacea
  • Protecting against certain skin cancers

Niacinamide (also called nicotinamide) is a form of vitamin B3 used in supplements and skin-care products. It is well established for preventing and treating vitamin B3 deficiency, and there is moderate evidence for some skin uses, but many popular claims are still being studied. It is generally well tolerated at usual doses, but high amounts should be discussed with your doctor or pharmacist.

Read the full Niacinamide monograph & all interactions
Medication

About Carbamazepine

What Is Carbamazepine Used For?

Brand names: Tegretol, Tegretol XR, Equetro, Carbatrol, Carnexiv

Carbamazepine is used to treat certain types of seizures — including partial seizures, generalized tonic-clonic (grand mal) seizures, and mixed seizure patterns. It works best for those specific seizure types; it does not appear to control absence (petit mal) seizures.

It is also prescribed to relieve the intense facial pain of trigeminal neuralgia — a nerve condition that causes sudden, severe pain along the face. It is not a general painkiller and shouldn't be used for ordinary aches and pains.

See full Carbamazepine drug information
Keep checking

Other Drugs & Niacinamide

Browse every other medication we’ve checked against Niacinamide — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
123Moderate
0Minor
2,706No known interaction
123 Moderate 2,706 No interaction
Moderate

123 interactions

Showing 60 of 123 moderate interactions — see all 123 on the Niacinamide page.

No interaction 2,706 drugs checked — show the list

We also checked Niacinamide against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,706 medications checked with no known interaction — see the full Niacinamide list.

See the full Niacinamide interactions page
See every supplement checked against Carbamazepine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Niacinamide monograph › Uses, safety, and every drug interaction in one place Carbamazepine supplement interactions › Every supplement checked against Carbamazepine, ranked by severity Carbamazepine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Niacinamide and Carbamazepine Together: Common Questions

Can you take Niacinamide with Carbamazepine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Niacinamide and Carbamazepine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Carbamazepine and Niacinamide?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.