Drug & supplement interaction

Turmeric + Grepafloxacin

Grepafloxacin brand name: Raxar.

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

Grepafloxacin falls into 2 drug categories that Turmeric can interact with; the most serious is rated moderate. Theoretically, turmeric might increase blood levels of OATP4C1 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Turmeric and Grepafloxacin

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Turmeric interacts with whole categories of medication. Grepafloxacin falls into 2 of those categories, so it can interact with Turmeric in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP)

1 of 2

Why this applies to Grepafloxacin

Grepafloxacin falls under ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) — the group Turmeric interacts with.

Theoretically, turmeric might increase blood levels of OATP4C1 substrates.
In vitro research shows that the turmeric constituent curcumin competitively inhibits OATP4C1 transport. This transporter is expressed in the kidney and facilitates the renal excretion of certain drugs. Theoretically, taking turmeric might decrease renal excretion of OATP substrates.
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 with turmeric and grepafloxacin (Raxar), an antibiotic in the fluoroquinolone family. Your kidneys use little 'shuttle' proteins, including one called OATP4C1, to help clear certain drugs out in your urine. In a lab dish, the curcumin in turmeric blocked that shuttle. So in theory, if that shuttle moves grepafloxacin too, less of the drug might get flushed out, leaving slightly more in your bloodstream.

If that happened, you might feel more of the usual side effects, like nausea, dizziness, or in rare cases heart rhythm changes. But I want to be honest: this is only test-tube and theory, not something proven in people. The amount of turmeric in food is very unlikely to matter. Before using concentrated turmeric capsules, just check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sato T, Yagi A, Yamauchi M, et al. The use of an antioxidant enables accurate evaluation of the interaction of curcumin on organic anion-transporting polypeptides 4C1 by preventing auto-oxidation. Int J Mol Sci 2024;25(2):991. PubMed
Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

2 of 2

Grepafloxacin also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, turmeric might increase levels of drugs metabolized by CYP1A2. However, research is conflicting.
In vitro and animal research show that the turmeric constituent, curcumin, inhibits CYP1A2. However, other in vitro research suggests that curcumin does not significantly affect CYP1A2.
Severity Minor 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 basic idea with turmeric and grepafloxacin (Raxar). Grepafloxacin is an active antibiotic, not a prodrug, and your liver partly clears it using an enzyme called CYP1A2. Some lab and animal studies hint that curcumin (the main compound in turmeric) might slow that enzyme down a bit. If that happened, grepafloxacin could linger longer in your body, which in theory could nudge up side effects like nausea, stomach upset, or dizziness.

That said, I want to keep this in perspective. The evidence is weak and conflicting, and it comes from test tubes and animals, not people. Everyday turmeric in food is very unlikely to matter. If you take concentrated curcumin capsules, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Thapliyal R, Deshpande SS, Maru GB. Mechanism(s) of turmeric-mediated protective effects against benzo(a)pyrene-derived DNA adducts. Cancer Lett 2002;175:79-88. PubMed
  2. Appiah-Opong, R., Commandeur, J. N., Vugt-Lussenburg, B., and Vermeulen, N. P. Inhibition of human recombinant cytochrome P450s by curcumin and curcumin decomposition products. Toxicology 6-3-2007;235(1-2):83-91. PubMed
  3. Price, R. J., Scott, M. P., Giddings, A. M., Walters, D. G., Stierum, R. H., Meredith, C., and Lake, B. G. Effect of butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole on cytochrome P450 forms in cultured human hepatocytes. Xenobiotica 2 PubMed
  4. Oetari, S., Sudibyo, M., Commandeur, J. N., Samhoedi, R., and Vermeulen, N. P. Effects of curcumin on cytochrome P450 and glutathione S-transferase activities in rat liver. Biochem Pharmacol 1-12-1996;51(1):39-45. 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

Turmeric Also Interacts With Other Medications

Turmeric has 1,055 moderate, 77 minor known drug interactions in our database — the Grepafloxacin one above is among them. If you take anything else, check it against the full list below.

Moderate 1,055 Minor 77 No known interaction 1,698 (incl. Grepafloxacin)
Taking anything else?

Check Another of Your Medications Against Turmeric

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

From our Q&A

Questions About Turmeric or Grepafloxacin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Turmeric or Grepafloxacin, 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 Grepafloxacin

This page covers Turmeric only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Grepafloxacin page lists 164 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Apple (major), Arsenic (major) and Cesium (major).

By severity: 9 major · 113 moderate · 42 minor.

From our pharmacist’s overview on the Grepafloxacin page

“A week on grepafloxacin (Raxar), a quinolone antibiotic, often comes with juice at breakfast, coffee through the day, maybe a probiotic for the stomach, and each of those shows up on this list. The nine major entries among these 164 deserve your attention first: grapefruit and other fruit juices can block the transporter that carries t…”

Reviewed by 2 · Jul 18, 2026

Open the Grepafloxacin interaction page

One more smart check

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

We hold 1,368 real supplement products containing Turmeric, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Turmeric. Your product may carry other ingredients that interact with Grepafloxacin too, on top of Turmeric — 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 Turmeric and Grepafloxacin 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 Turmeric
Top 5%

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

29 days ago today
Medication Grepafloxacin
Steady interest

#1,764 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 Turmeric

What is Turmeric?

Turmeric
  • Joint pain and arthritis
  • Inflammation
  • Digestive upset
  • Antioxidant support
  • Skin conditions

Turmeric is a popular spice whose main active compounds, curcuminoids, are studied mostly for inflammation and joint pain. Some research is promising, but quality is mixed and curcumin is poorly absorbed on its own. For most people, dietary amounts are safe, but talk to your pharmacist or doctor before taking concentrated supplements, especially if you are pregnant, nursing, or have a medical condition.

Read the full Turmeric monograph & all interactions
Keep checking

Other Drugs & Turmeric

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

0Major
1,055Moderate
77Minor
1,697No known interaction
1,055 Moderate 77 Minor 1,697 No interaction
Moderate

1,055 interactions

Showing 60 of 1,055 moderate interactions — see all 1,055 on the Turmeric page.

Minor

77 interactions

Showing 60 of 77 minor interactions — see all 77 on the Turmeric page.

No interaction 1,697 drugs checked — show the list

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

Showing the 60 most looked-up of 1,697 medications checked with no known interaction — see the full Turmeric list.

See the full Turmeric interactions page
See every supplement checked against Grepafloxacin, 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
Turmeric monograph › Uses, safety, and every drug interaction in one place Grepafloxacin supplement interactions › Every supplement checked against Grepafloxacin, ranked by severity 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 Turmeric and Grepafloxacin Together: Common Questions

Can you take Turmeric with Grepafloxacin?
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.
Why are there 2 interactions listed for Turmeric and Grepafloxacin?
Grepafloxacin belongs to more than one drug category, and Turmeric interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Turmeric and Grepafloxacin 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 Grepafloxacin and Turmeric?

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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.