The short answer
Aluminum-containing antacids can reduce absorption of oral levofloxacin. The current tablet label recommends a gap of at least 2 hours before or after the antacid. This concerns medicinal aluminum products in the digestive tract, not every trace exposure to aluminum.
What this answer covers
Oral levofloxacin tablets and aluminum-containing oral antacids. The direct trial used aluminum hydroxide; dietary traces, skin products and injected treatment are outside that finding.
- Supplement or preparation
- Aluminum
- Medication ingredient
- levofloxacin
What did the study show?
In a randomized crossover study, aluminum hydroxide taken with the antibiotic reduced relative bioavailability to 56% of the value with the antibiotic alone. The study used a 100 mg levofloxacin preparation and 1 g aluminum hydroxide. This was a measurement of medicine reaching the bloodstream, not a demonstration that an individual patient’s infection would fail treatment.
How should the doses be separated?
The levofloxacin tablet label uses the same interval in both directions: at least 2 hours before or 2 hours after the aluminum antacid. This differs from the instructions for some other fluoroquinolone antibiotics. If you change antibiotics, check the new bottle rather than carrying over a schedule from the previous medicine.
Which aluminum products are covered?
Aluminum hydroxide is the directly studied antacid. A combined antacid may contain magnesium as well, so the complete ingredient list matters. The study does not turn aluminum in food, a cosmetic, or an unrelated compound into the same exposure. An oral absorption finding also does not provide dosing instructions for levofloxacin administered by injection.
How can I keep treatment on track?
Bring the antacid and antibiotic instructions to your pharmacist if fitting both into the day is difficult. Follow the prescribed antibiotic schedule, including any adjustment already made for kidney function. If you took the two close together, ask for individual advice rather than taking an extra antibiotic tablet. The study percentage cannot calculate a replacement dose for you.
Evidence and practical considerations
Absorption & effectiveness
Aluminum-containing antacids can reduce absorption of oral levofloxacin. The current tablet label recommends a gap of at least 2 hours before or after the antacid. This concerns medicinal aluminum products in the digestive tract, not every trace exposure to aluminum.
- Exact scope
- aluminum hydroxide and other aluminum-containing oral antacids with oral levofloxacin hemihydrate tablets with strengths expressed as levofloxacin
- Medication form and route
- oral
- Timing or duration
- An overlapping oral dose can impair absorption; direct study used a single 100 mg antibiotic dose.
What remains uncertain
- One early preparation-specific pharmacokinetic trial and current labeling; no quantified infection treatment failure or all-salt equivalence.
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: aluminum hydroxide and other aluminum-containing oral antacids.
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: aluminum hydroxide and other aluminum-containing oral antacids.
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: aluminum hydroxide and other aluminum-containing oral antacids.
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: b743fdb15198118c
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.