What the FDA labels say about taking them together
Heparin and protamine
Protamine's FDA label of April 29, 2025 names heparin in its boxed warning section; the heparin labels PlainMeds reads (4) do not name protamine. The protamine label: “Protamine sulfate should not be given when bleeding occurs without prior heparin use.”
Check it at the source: the heparin FDA label on DailyMed (effective November 28, 2025, Fresenius Kabi USA, LLC); the protamine FDA label on DailyMed (effective April 29, 2025, Fresenius Kabi USA, LLC).
What does the heparin label say about protamine?
Heparin's label (effective November 28, 2025) and its 3 other brand-application labels do not name protamine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Heparin Sodium), Fresenius Kabi USA, LLC, effective November 28, 2025 (SPL set d55b4a63-0c04-4874-b74f-9e9b9e8b008c), via openFDA; the full label on DailyMed
What does the protamine label say about heparin?
Protamine label, boxed warningProtamine sulfate should not be given when bleeding occurs without prior heparin use.
Protamine label, warningsHyperheparinemia or bleeding has been reported in experimental animals and in some patients 30 minutes to 18 hours after cardiac surgery (under cardiopulmonary bypass) in spite of complete neutralization of heparin by adequate doses of protamine sulfate at the end of the operation.
Source: FDA drug label (Protamine Sulfate), Fresenius Kabi USA, LLC, effective April 29, 2025 (SPL set c76876da-b9a8-45d0-9278-7df3288d3a06), 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
| Heparin | Protamine | |
|---|---|---|
| Labeled for | Blood clots (DVT and PE), Atrial fibrillation | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.18 per mL 5,000 unit/mL vial | n/a |
| Shortage now | In shortage | 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