Drug & supplement interaction

Niacinamide + Cilostazol

Cilostazol brand name: Pletal.

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

Niacinamide has a moderate interaction with Cilostazol. Theoretically, niacinamide may have additive effects when used with anticoagulant or antiplatelet drugs, especially in patients on hemodialysis.

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

Niacinamide and Cilostazol

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Cilostazol

Cilostazol falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Niacinamide interacts with.

Theoretically, niacinamide may have additive effects when used with anticoagulant or antiplatelet drugs, especially in patients on hemodialysis.
Several cases of thrombocytopenia have been reported for hemodialysis patients treated with niacinamide 1 gram daily. Hemodialysis patients receiving niacinamide had almost a three-fold higher risk of developing thrombocytopenia when compared with those receiving placebo.
Severity Moderate Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Here's the gist with cilostazol (Pletal) and niacinamide. Cilostazol is an antiplatelet medicine, meaning it makes your platelets a little less sticky to help blood flow through your leg arteries. The theoretical concern is that high-dose niacinamide might add to that effect, slightly raising the chance of easy bruising or bleeding. There have also been a few reports of low platelet counts in dialysis patients taking about 1 gram of niacinamide daily.

Honestly, this is weak, anecdotal evidence, and everyday vitamin B3 amounts are very unlikely to cause trouble. Cilostazol isn't a prodrug, so niacinamide doesn't change how it activates. If you take concentrated niacinamide or are on dialysis, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rottembourg JB, Launay-Vacher V, Massard J. Thrombocytopenia induced by nicotinamide in hemodialysis patients. Kidney Int. 2005;68(6):2911-2. PubMed
  2. Zhang Y, Ma T, Zhang P. Efficacy and safety of nicotinamide on phosphorus metabolism in hemodialysis patients: A systematic review and meta-analysis. Medicine (Baltimore). 2018;97(41):e12731. PubMed

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 Cilostazol 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. Cilostazol)
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 Cilostazol

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 Cilostazol, 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 Cilostazol

This page covers Niacinamide only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cilostazol page lists 286 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Grapefruit (major), Piracetam (major) and St. John's Wort (major).

By severity: 5 major · 240 moderate · 41 minor.

Open the Cilostazol 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 Cilostazol 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 Cilostazol 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%

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

29 days ago today
Medication Cilostazol
Steady interest

#1,763 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 Cilostazol

What Is Cilostazol Used For?

Brand name: Pletal

Cilostazol tablets are approved to reduce the symptoms of intermittent claudication (cramping leg pain that comes on during walking due to reduced blood flow in the arteries). The goal is to help you walk farther before pain forces you to stop.

See full Cilostazol 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 Cilostazol, 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 Cilostazol supplement interactions › Every supplement checked against Cilostazol, ranked by severity Cilostazol 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 Cilostazol Together: Common Questions

Can you take Niacinamide with Cilostazol?
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 Cilostazol 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 Cilostazol 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.