Drug & supplement interaction

Iron + Grepafloxacin

Grepafloxacin brand name: Raxar.

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

Iron has a moderate interaction with Grepafloxacin. Iron might decrease levels of quinolone antibiotics by reducing their absorption.

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

Iron and Grepafloxacin

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

Moderate

QUINOLONE ANTIBIOTICS

Why this applies to Grepafloxacin

Grepafloxacin falls under QUINOLONE ANTIBIOTICS — the group Iron interacts with.

Iron might decrease levels of quinolone antibiotics by reducing their absorption.
Advise patients to separate quinolone antibiotics and iron doses by at least 2 hours. Iron decreases the absorption of quinolones due to formation of insoluble complexes in the gastrointestinal tract.
Severity Moderate Likelihood Probable Evidence D

Interaction 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..

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

Here's the simple version: when you swallow iron and grepafloxacin (Raxar) close together, the iron can grab onto the antibiotic right in your gut and form a clump your body can't absorb well. That means less antibiotic actually gets into your bloodstream, so it may not knock out the infection the way it should. This isn't about the drug building up or causing extra side effects, it's about it being weakened.

The good news is the fix is easy. Most pharmacists suggest spacing the two doses by at least 2 hours so the iron has time to clear before the antibiotic comes through. This is based mainly on how these drugs behave chemically rather than big studies, but it's a sensible, well-known precaution. Check the timing with your pharmacist to be safe.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.

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

Iron Also Interacts With Other Medications

Iron has 78 moderate, 1 minor known drug interactions in our database — the Grepafloxacin one above is one of them. If you take anything else, check it against the full list below.

Moderate 78 Minor 1 No known interaction 2,751 (incl. Grepafloxacin)
Taking anything else?

Check Another of Your Medications Against Iron

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

Everything else you take

See Every Supplement That Interacts With Grepafloxacin

This page covers Iron 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 Iron as Part of a Dietary Supplement Product? Check It for Interactions

We hold 16,325 real supplement products containing Iron, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Iron. Your product may carry other ingredients that interact with Grepafloxacin too, on top of Iron — 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 Iron 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 Iron
Top 1%

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

29 days ago today
Medication Grepafloxacin
Steady interest

#2,252 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 Iron

What is Iron?

  • Iron-deficiency anemia
  • Low iron stores during pregnancy
  • Fatigue from iron deficiency
  • Heavy menstrual blood loss
  • Restless legs syndrome (with low iron)

Iron is an essential mineral your body needs to make hemoglobin and carry oxygen in the blood. Supplements are mainly useful for treating or preventing iron deficiency and iron-deficiency anemia, ideally after a blood test confirms you are low. Because too much iron can be harmful, take it only when needed and under the guidance of a pharmacist or doctor.

Read the full Iron monograph & all interactions
Keep checking

Other Drugs & Iron

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

0Major
78Moderate
1Minor
2,750No known interaction
78 Moderate 1 Minor 2,750 No interaction
Moderate

78 interactions

Showing 60 of 78 moderate interactions — see all 78 on the Iron page.

Minor

1 interaction

No interaction 2,750 drugs checked — show the list

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

Showing the 60 most looked-up of 2,750 medications checked with no known interaction — see the full Iron list.

See the full Iron 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
Iron 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 Iron and Grepafloxacin Together: Common Questions

Can you take Iron 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.
How serious is the Iron 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 Iron?

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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.