What the FDA labels say about taking them together
Piperacillin/tazobactam and tobramycin
Piperacillin/tazobactam's FDA label of July 21, 2025 names tobramycin in its drug interactions section; the tobramycin labels PlainMeds reads (4) do not name piperacillin/tazobactam. The piperacillin/tazobactam label: “ZOSYN administration can significantly reduce tobramycin concentrations in hemodialysis patients.”
Check it at the source: the piperacillin/tazobactam FDA label on DailyMed (effective July 21, 2025, ONESOURCE SPECIALTY PHARMA LIMITED); the tobramycin FDA label on DailyMed (effective November 1, 2023, Bausch & Lomb Incorporated).
What does the piperacillin/tazobactam label say about tobramycin?
Piperacillin/tazobactam label, drug interactionsDRUG INTERACTIONS Piperacillin and tazobactam administration can significantly reduce tobramycin concentrations in hemodialysis patients.
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
What does the tobramycin label say about piperacillin/tazobactam?
Tobramycin's label (effective November 1, 2023) 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 (Tobramycin), Bausch & Lomb Incorporated, effective November 1, 2023 (SPL set a5693ec9-d2f7-4d45-90b0-a113c54840d7), 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
| Piperacillin/tazobactam | Tobramycin | |
|---|---|---|
| Labeled for | Bacterial infections | Bacterial infections, Urinary tract infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $3.49 per vial 3.375 g vial | $1.08 per mL 300 mg/5 mL ampule |
| Shortage now | A presentation being discontinued | 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