What kind of interaction is it?

Timing-sensitive: the two substances can be taken on the same day but should be separated by a minimum time window.

Is this interaction backed by published research?

Yes. NutriStack lists 1 citation row for the Fosfomycin + Iron pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Prescription·timing-sensitive·Emerging evidence

Fosfomycin + Iron

Q: Can I take Fosfomycin and Iron together?

Yes, if you separate them in time. Fosfomycin and Iron have a documented timing-sensitive interaction. Oral iron salts are polyvalent cations known to chelate many antibiotics in the gut. Iron can plausibly bind fosfomycin and reduce its absorption, potentially lowering the urinary antibiotic concentration needed for the single-dose treatment of an uncomplicated UTI.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored timing-sensitive row.

Timing Sensitive Emerging evidence

Oral iron salts are polyvalent cations known to chelate many antibiotics in the gut. Iron can plausibly bind fosfomycin and reduce its absorption, potentially lowering the urinary antibiotic concentration needed for the single-dose treatment of an uncomplicated UTI.

Supplement × Prescription

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

Fosfomycin and Iron

Pair type

Timing Sensitive

Evidence

Emerging

Source citations

Scope

Supplement × Prescription

Last verified

June 4, 2026

Timing SensitiveEmerging evidence

What is happening. Oral iron salts are polyvalent cations known to chelate many antibiotics in the gut. Iron can plausibly bind fosfomycin and reduce its absorption, potentially lowering the urinary antibiotic concentration needed for the single-dose treatment of an uncomplicated UTI.

Mechanism. Polyvalent cation (iron) chelation forms an insoluble fosfomycin-iron complex in the gastrointestinal tract, reducing oral bioavailability.

Recommendation. Separate oral iron supplements from the single fosfomycin dose. Since fosfomycin is taken once, take the antibiotic alone and resume iron the following day or several hours apart.

Stack Score

How it moves the number.

Effect on the composite score

If both Fosfomycin and Iron are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).

The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Patel SS, Balfour JA, Bryson HM. Fosfomycin tromethamine: pharmacokinetic properties and effect of divalent and polyvalent cations on oral absorption. Drugs. 1997.Needs sourceNo link

Check your full routine

One pair was the worked example.

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Open the interaction checker → Browse the research index