What the FDA labels say about taking them together
Chloramphenicol and penicillin g
Penicillin g's FDA label of September 16, 2020 names chloramphenicol in its drug interactions section; the chloramphenicol label PlainMeds reads does not name penicillin g.
Check it at the source: the chloramphenicol FDA label on DailyMed (effective October 10, 2024, Fresenius Kabi USA, LLC); the penicillin g FDA label on DailyMed (effective September 16, 2020, Sandoz Inc).
What does the chloramphenicol label say about penicillin g?
Chloramphenicol's label (effective October 10, 2024) does not name penicillin g in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Chloramphenicol Sodium Succinate), Fresenius Kabi USA, LLC, effective October 10, 2024 (SPL set aed29594-211d-49ef-813f-131975a8d0e3), via openFDA; the full label on DailyMed
What does the penicillin g label say about chloramphenicol?
Penicillin g label, drug interactionsDrug Interactions Bacteriostatic antibacterials (i.e., chloramphenicol, erythromycins, sulfonamides or tetracyclines) may antagonize the bactericidal effect of penicillin, and concurrent use of these drugs should be avoided.
Source: FDA drug label (Penicillin G Potassium), Sandoz Inc, effective September 16, 2020 (SPL set 91950983-4884-40d1-abd8-bcc953d61b7f), 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
| Chloramphenicol | Penicillin g | |
|---|---|---|
| Labeled for | n/a | Bacterial infections |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| Shortage now | No current entry | 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