What the FDA labels say about taking them together
Cilastatin/imipenem and probenecid
Cilastatin/imipenem's FDA label of July 5, 2024 names probenecid in its drug interactions section; the probenecid label PlainMeds reads does not name cilastatin/imipenem. The cilastatin/imipenem label: “Concomitant administration of PRIMAXIN and probenecid results in increases in the plasma level and half-life of imipenem.”
Check it at the source: the cilastatin/imipenem FDA label on DailyMed (effective July 5, 2024, Merck Sharp & Dohme LLC); the probenecid FDA label on DailyMed (effective January 5, 2021, Lannett Company, Inc.).
What does the cilastatin/imipenem label say about probenecid?
Cilastatin/imipenem label, drug interactionsConcomitant administration of PRIMAXIN and probenecid results in increases in the plasma level and half-life of imipenem.
Source: FDA drug label (PRIMAXIN IV), Merck Sharp & Dohme LLC, effective July 5, 2024 (SPL set f41d8abd-7792-4918-1b93-bd83ea01955e), via openFDA; the full label on DailyMed
What does the probenecid label say about cilastatin/imipenem?
Probenecid's label (effective January 5, 2021) does not name cilastatin/imipenem in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Probenecid), Lannett Company, Inc., effective January 5, 2021 (SPL set ab497fd8-00c3-4364-b003-b39d21fbdf38), 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
| Cilastatin/imipenem | Probenecid | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | Gout |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.636 per tablet 500 mg tablet |
| 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