What the FDA labels say about taking them together
Cyclophosphamide and doxorubicin
Cyclophosphamide's FDA label (Cyclophosphamide) of April 21, 2025 names doxorubicin in its drug interactions section, and doxorubicin's label names cyclophosphamide too. The doxorubicin label: “… mediastinum or concomitant therapy with other known cardiotoxic agents, such as cyclophosphamide and trastuzumab.”
Check it at the source: the cyclophosphamide FDA label on DailyMed (effective January 19, 2026, Amneal Pharmaceuticals LLC); the doxorubicin FDA label on DailyMed (effective May 5, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the cyclophosphamide label say about doxorubicin?
Cyclophosphamide label (Eugia US LLC, April 21, 2025), drug interactionsUse of protease inhibitor-based regimens was found to be associated with a higher incidence of infections and neutropenia in patients receiving cyclophosphamide, doxorubicin, and etoposide (CDE) than use of a Non-Nucleoside Reverse Transcriptase Inhibitor-based regimen.
Source: FDA drug label (Cyclophosphamide, NDA210735), Eugia US LLC, effective April 21, 2025 (SPL set 3c1eb470-0bba-457d-94e3-b9508f0d398a), via openFDA
Source: FDA drug label (Cyclophosphamide), Amneal Pharmaceuticals LLC, effective January 19, 2026 (SPL set 520bfe39-dfd5-4a20-9a37-80078afded0d), via openFDA; the full label on DailyMed
What does the doxorubicin label say about cyclophosphamide?
Doxorubicin label, warnings and precautionsThere is an additive or potentially synergistic increase in the risk of cardiomyopathy in patients who have received radiotherapy to the mediastinum or concomitant therapy with other known cardiotoxic agents, such as cyclophosphamide and trastuzumab.
Source: FDA drug label (Doxorubicin Hydrochloride), Pfizer Laboratories Div Pfizer Inc, effective May 5, 2026 (SPL set 1fd148fb-0fbc-4b6f-b790-23546fb46a71), 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
| Cyclophosphamide | Doxorubicin | |
|---|---|---|
| Labeled for | Leukemia, lymphoma and myeloma | Leukemia, lymphoma and myeloma, Breast cancer |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.67 per capsule 50 mg capsule | 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