Lanthanum and Ciprofloxacin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ciprofloxacin
No brand names on recordLanthanum
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced bioavailability of quinolone antibiotics
Interaction Deep Dive
Use caution with coadministration of lanthanum and oral quinolone antibiotics, as reduced quinolone bioavailability may occur. Ciprofloxacin Cmax and AUC were reduced by 56% and 54%, respectively, when coadministered with lanthanum. lf concurrent use is required, administer oral quinolones at least 1 hour before or 4 hours after lanthanum. If only a short course of treatment with a quinolone is needed, consider eliminating the lanthanum doses normally scheduled near quinolone administration to improve quinolone absorption1.
Why it happens (mechanism)
Binding of lanthanum carbonate with anionic groups of quinolone antibiotics
Literature reports
1 report — tap to read
a) Ciprofloxacin Cmax and AUC were reduced by 56% and 54%, respectively, when a single dose of ciprofloxacin 750 mg oral was administered to healthy subjects treated with a lanthanum carbonate 3 g/day regimen in a randomized, 2-way crossover study 1.
Common questions
Can I take Lanthanum and Ciprofloxacin together?
Reduced bioavailability of quinolone antibiotics Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lanthanum and Ciprofloxacin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Lanthanum or Ciprofloxacin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: FOSRENOL(R) oral chewable tablets oral powder, lanthanum carbonate oral chewable tablets oral powder. Shire US Inc. (per FDA), Wayne, IN, 2014. DailyMed
Keep reading about Ciprofloxacin
Keep reading about Lanthanum
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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