What the FDA labels say about taking them together
Ampicillin and lanthanum
Lanthanum's FDA label of December 31, 2024 names ampicillin in its drug interactions section; the ampicillin label PlainMeds reads does not name lanthanum. The lanthanum label: “Binding to Antacids There is a potential for FOSRENOL to interact with compounds which bind to cationic antacids; therefore, do not administer such compounds within 2 hours of dosing with FOSRENOL. …”
Check it at the source: the ampicillin FDA label on DailyMed (effective February 21, 2025, Sandoz Inc); the lanthanum FDA label on DailyMed (effective December 31, 2024, Takeda Pharmaceuticals America, Inc.).
What does the ampicillin label say about lanthanum?
Ampicillin's label (effective February 21, 2025) does not name lanthanum in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Ampicillin), Sandoz Inc, effective February 21, 2025 (SPL set 64a04e8c-8f78-46b3-8f45-56ef225a4f74), via openFDA; the full label on DailyMed
What does the lanthanum label say about ampicillin?
Lanthanum label, drug interactionsBinding to Antacids There is a potential for FOSRENOL to interact with compounds which bind to cationic antacids (i.e., aluminum-, magnesium-, or calcium-based); therefore, do not administer such compounds within 2 hours of dosing with FOSRENOL. Examples of relevant classes of compounds where antacids have been demonstrated to reduce bioavailability include antibiotics (such as quinolones, ampicillin, and tetracyclines), thyroid hormones, ACE inhibitors, statin lipid regulators, and anti-malarials.
Source: FDA drug label (Fosrenol), Takeda Pharmaceuticals America, Inc., effective December 31, 2024 (SPL set f10776b2-2c25-4343-aabe-68f302e5cb54), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Ampicillin | Lanthanum | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.441 per capsule 500 mg capsule | $3.15 per tablet 1,000 mg tablet chw |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once