What the FDA labels say about taking them together
Heparin and piperacillin/tazobactam
Piperacillin/tazobactam's FDA label of July 21, 2025 names heparin in its drug interactions section; the heparin labels PlainMeds reads (4) do not name piperacillin/tazobactam. The piperacillin/tazobactam label: “Monitor coagulation parameters in patients receiving ZOSYN and heparin or oral anticoagulants.”
Check it at the source: the heparin FDA label on DailyMed (effective November 28, 2025, Fresenius Kabi USA, LLC); the piperacillin/tazobactam FDA label on DailyMed (effective July 21, 2025, ONESOURCE SPECIALTY PHARMA LIMITED).
What does the heparin label say about piperacillin/tazobactam?
Heparin's label (effective November 28, 2025) and its 3 other brand-application labels do not name piperacillin/tazobactam 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 piperacillin/tazobactam label say about heparin?
Piperacillin/tazobactam label, drug interactionsMonitor kidney function in patients receiving piperacillin and tazobactam and vancomycin. ( 7.3 ) Monitor coagulation parameters in patients receiving piperacillin and tazobactam and heparin or oral anticoagulants. ( 7.4 ) Piperacillin and tazobactam may prolong the neuromuscular blockade of vecuronium and other non-depolarizing muscle relaxants.
Zosyn label (Baxter Healthcare Corporation, May 15, 2026), drug interactionsMonitor coagulation parameters in patients receiving ZOSYN and heparin or oral anticoagulants.
Piperacillin And Tazobactam And Sodium Chloride label (B. Braun Medical Inc., May 8, 2026), drug interactionsMonitor kidney function in patients receiving Piperacillin and Tazobactam for Injection and Sodium Chloride Injection and vancomycin. ( 7.3 ) Monitor coagulation parameters in patients receiving Piperacillin and Tazobactam for Injection and Sodium Chloride Injection and heparin or oral anticoagulants. ( 7.4 ) Piperacillin and Tazobactam for Injection and Sodium Chloride Injection may prolong the neuromuscular blockade of vecuronium and other non-depolarizing neuromuscular blockers.
Source: FDA drug label (Zosyn, NDA050750), Baxter Healthcare Corporation, effective May 15, 2026 (SPL set 8db6bd91-2106-4bfd-8cc8-38aaf1e18d17), via openFDA
Source: FDA drug label (Piperacillin And Tazobactam And Sodium Chloride, NDA206056), B. Braun Medical Inc., effective May 8, 2026 (SPL set a63ca653-27d4-45fe-a744-77e0efe45220), via openFDA
Source: FDA drug label (piperacillin and tazobactam), ONESOURCE SPECIALTY PHARMA LIMITED, effective July 21, 2025 (SPL set 28258745-12e4-4f0f-b318-4a1a1bebc928), 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 | Piperacillin/tazobactam | |
|---|---|---|
| Labeled for | Blood clots (DVT and PE), Atrial fibrillation | Bacterial infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.18 per mL 5,000 unit/mL vial | $3.49 per vial 3.375 g vial |
| Shortage now | In shortage | A presentation being discontinued |
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