NutriStack
Calcium Carbonate and Levofloxacin, timing-sensitive.
Calcium carbonate binds levofloxacin in the gut and reduces its absorption substantially. This applies whether calcium carbonate is taken as an antacid or as a calcium supplement.
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
- Calcium Carbonate and Levofloxacin
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Strong
- Source citations
- 2 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. Calcium carbonate binds levofloxacin in the gut and reduces its absorption substantially. This applies whether calcium carbonate is taken as an antacid or as a calcium supplement.
Mechanism. Ca2+ chelates the 3-carboxyl and 4-oxo groups on the fluoroquinolone core, forming insoluble complexes that block enterocyte uptake.
Recommendation. Take levofloxacin at least 2 hours before or 2 hours after calcium carbonate. Do not co-administer.
Minimum separation. 120
Sources (2)
- Fish DN, Chow AT. The clinical pharmacokinetics of levofloxacin. Clin Pharmacokinet. 1997;32(2):101-19. PMID 9068926
- Wiesner A, Zagrodzki P, Gawalska A, Paśko P. Together or Apart? Revealing the Impact of Dietary Interventions on Bioavailability of Quinolones: A Systematic Review with Meta-analyses. Clin Pharmacokinet. 2024;63(6):773-818. PMID 38807006
Stack Score
How this pair moves the number.
Effect on the composite score
If both Calcium Carbonate and Levofloxacin 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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