NutriStack
Ciprofloxacin and Iron, timing-sensitive.
Iron strongly chelates ciprofloxacin, forming insoluble iron-quinolone complexes that dramatically reduce ciprofloxacin absorption and efficacy. This interaction can cause antibiotic treatment failure, which is particularly dangerous during active infection.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Ciprofloxacin and Iron
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Strong
- Source citations
- 6 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Timing Sensitive · Strong evidence
Timing Sensitive
What is happening. Iron strongly chelates ciprofloxacin, forming insoluble iron-quinolone complexes that dramatically reduce ciprofloxacin absorption and efficacy. This interaction can cause antibiotic treatment failure, which is particularly dangerous during active infection.
Mechanism. Iron (Fe2+/Fe3+) forms tight chelate complexes with ciprofloxacin's keto-carboxylate moiety. Iron is one of the most potent chelators of fluoroquinolones, reducing bioavailability by 30-90% depending on the iron dose and formulation.
Recommendation. Separate ciprofloxacin and iron supplements by at least 2 hours (take ciprofloxacin 2 hours before or 6 hours after iron). Do not take them together under any circumstances during active antibiotic treatment.
Minimum separation. 120
Sources (6)
- Polk RE et al. Effect of ferrous sulfate and multivitamins with zinc on absorption of ciprofloxacin in normal volunteers. Antimicrob Agents Chemother. 1989;33(11):1841-1844. PMID 2610487
- Alves C, Mendes D, Marques FB. Fluoroquinolones and the risk of tendon injury: a systematic review and meta-analysis.. European Journal of Clinical Pharmacology. 2019. PMID 31270563
- Fischer JAJ, Cherian AM, Bone JN, Karakochuk CD. The effects of oral ferrous bisglycinate supplementation on hemoglobin and ferritin concentrations in adults and children: a systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews. 2023. PMID 36728680
- Rehman T, Agrawal R, Ahamed F et al.. Optimal dose and duration of iron supplementation for treating iron deficiency anaemia in children and adolescents: A systematic review and meta-analysis. PLoS One. 2025. PMID 39951396
- Gutema BT, Sorrie MB, Megersa ND et al.. Effects of iron supplementation on cognitive development in school-age children: Systematic review and meta-analysis. PLoS One. 2023. PMID 37368919
- Hansen R, Sejer EPF, Holm C, Schroll JB. Iron supplements in pregnant women with normal iron status: A systematic review and meta-analysis. Acta Obstetricia et Gynecologica Scandinavica. 2023. PMID 37403900
Stack Score
How this pair moves the number.
Effect on the composite score
If both Ciprofloxacin 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 documented at /methodology/stack-score.
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