What the FDA labels say about taking them together
Chloramphenicol and cyanocobalamin
Cyanocobalamin's FDA label (Nascobal) of March 1, 2024 names chloramphenicol in its drug interactions section; the chloramphenicol label PlainMeds reads does not name cyanocobalamin. The cyanocobalamin label: “DRUG INTERACTIONS Chloramphenicol may decrease the efficacy of NASCOBAL when used for treatment of anemia.”
Check it at the source: the chloramphenicol FDA label on DailyMed (effective October 10, 2024, Fresenius Kabi USA, LLC); the cyanocobalamin FDA label on DailyMed (effective October 31, 2023, American Regent, Inc.).
What does the chloramphenicol label say about cyanocobalamin?
Chloramphenicol's label (effective October 10, 2024) does not name cyanocobalamin 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 cyanocobalamin label say about chloramphenicol?
Nascobal label (Par Health USA, LLC, March 1, 2024), drug interactionsDRUG INTERACTIONS Chloramphenicol may decrease the efficacy of NASCOBAL when used for treatment of anemia.
Source: FDA drug label (Nascobal, NDA021642), Par Health USA, LLC, effective March 1, 2024 (SPL set 697e0e52-c01b-4b53-9994-f79c46eb6b4f), via openFDA
Source: FDA drug label (Cyanocobalamin), American Regent, Inc., effective October 31, 2023 (SPL set 2fb653d6-e2b2-4969-831b-c0dc37b9c0cc), 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 | Cyanocobalamin | |
|---|---|---|
| Labeled for | n/a | Anemia |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $1.47 per mL 1,000 mcg/mL vial |
| 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