The short answer
Magnesium-containing antacids can reduce absorption of oral levofloxacin. Current tablet instructions place these products at least 2 hours before or after the antibiotic. Magnesium oxide was tested directly; that result does not give an exact effect size for magnesium glycinate or every other supplement form.
What this answer covers
Oral levofloxacin tablets with magnesium oxide or magnesium-containing antacid products. Other nutritional salts require product-specific applicability; low blood magnesium is a separate issue.
- Supplement or preparation
- Magnesium
- Medication ingredient
- levofloxacin
What is the direct evidence?
Healthy volunteers received magnesium oxide 500 mg with a 100 mg levofloxacin preparation in a crossover study. Relative antibiotic bioavailability fell to 78% of its control value. Unlike a mixed-antacid trial, this experiment specifically tested magnesium oxide. It still cannot tell us the precise effect of every other magnesium salt or predict an infection outcome.
Does magnesium glycinate have the same result?
Magnesium glycinate was not the preparation tested in the retrieved experiment. Current labeling includes magnesium-containing antacids and patient guidance includes named magnesium products, which are reasons to check the schedule. They should not be presented as a clinical trial of a particular glycinate capsule. The form, elemental amount and other minerals in a supplement should remain part of the assessment.
How far apart should I take them?
For the listed magnesium products and oral levofloxacin tablets, use a minimum 2-hour gap on either side of the antibiotic dose. A pharmacist can adapt the daily schedule to the exact product and prescription. Meal instructions for a levofloxacin oral solution differ from those for tablets, so the formulation matters as well as the mineral.
Is this the same as having low magnesium?
No. A blood magnesium deficiency concerns the body’s electrolyte balance; this interaction concerns what happens when an oral mineral and antibiotic overlap in the gut. Do not stop medically directed replacement because of that distinction without a plan. Tell the prescriber about a documented deficiency and ask how to coordinate any needed treatment.
Evidence and practical considerations
Absorption & effectiveness
Magnesium-containing antacids can reduce absorption of oral levofloxacin. Current tablet instructions place these products at least 2 hours before or after the antibiotic. Magnesium oxide was tested directly; that result does not give an exact effect size for magnesium glycinate or every other supplement form.
- Exact scope
- oral magnesium oxide and magnesium-containing antacids, with exact nutritional salt retained with oral levofloxacin hemihydrate tablets with strengths expressed as levofloxacin
- Medication form and route
- oral
- Timing or duration
- Concurrent single doses studied; overlapping oral administration can matter throughout treatment.
What remains uncertain
- Small early study at a 100 mg antibiotic dose. Different magnesium salts, elemental amounts and patient groups are not equally studied.
Factors that may matter: exact salt and dose; order and interval between doses; other mineral ingredients; oral tablet versus other routes.
Read the supporting source summaries
Source 1: regulatory product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral levofloxacin tablets.
Directs a minimum 2-hour gap before or after magnesium/aluminum antacids, iron and zinc-containing vitamin/mineral products. Calcium is not specifically named in this chelation instruction. Tablets may be taken with or without food.
How this applies: The label defines the pure (-)-(S) ofloxacin enantiomer hemihydrate as levofloxacin. This supports the exact oral formulation under parent RxCUI 82122; racemic ofloxacin, IV use and eye drops are not substituted. Article-specific counterparty: oral magnesium oxide and magnesium-containing antacids, with exact nutritional salt retained.
Does not quantify each mineral salt or combination product; a listed interaction does not establish the magnitude of clinical treatment failure.
Source 2: human pharmacokinetic study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Healthy male volunteers in three randomized crossover studies; subgroup sizes were not given in the inspected abstract.
Relative antibiotic bioavailability was 56% with aluminum hydroxide, 78% with magnesium oxide, and 81% with ferrous sulfate. Calcium carbonate did not influence bioavailability under the tested regimen.
How this applies: DR-3355 is defined in the original abstract by the same pure (-)-(S) enantiomer hemihydrate chemical structure specified in current levofloxacin labeling, not racemic ofloxacin. Direct for the named salts with that oral preparation. Article-specific counterparty: oral magnesium oxide and magnesium-containing antacids, with exact nutritional salt retained.
Small early pharmacokinetic studies used a 100 mg dose rather than current usual tablet strengths. No infection outcomes. Results differ by mineral and cannot be treated as one class effect. Full clinical paper was not assessed; inspected source is the original author abstract.
Source 3: institutional patient medication guidance
medlineplus.gov · Source check Sep 10, 2026
Population: People using oral levofloxacin tablets or solution.
Advises at least 2 hours of separation in either direction for the named products. Distinguishes tablet food instructions from the oral solution and advises discussing exact medicines and supplements.
How this applies: Supports practical scheduling for named oral products; the article remains restricted to tablets where product-label evidence is used. Article-specific counterparty: oral magnesium oxide and magnesium-containing antacids, with exact nutritional salt retained.
Patient guidance is not a separate clinical experiment. No quantified individual zinc salt or multivitamin effect; calcium is not specifically included in this sentence.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original product guidance and clinical studies checked; complete private article drafted with exact preparation limits and claim dispositions. | |
| Research summary published |
Article revision: c54a926196f0ed61
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.