What the FDA labels say about taking them together
Furosemide and tamsulosin
Tamsulosin's FDA label of December 1, 2025 names furosemide in its drug interactions section; the furosemide labels PlainMeds reads (4) do not name tamsulosin. The tamsulosin label: “While furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride C max and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the tamsulosin hydrochloride …”
Check it at the source: the furosemide FDA label on DailyMed (effective September 30, 2025, Validus Pharmaceuticals LLC); the tamsulosin FDA label on DailyMed (effective December 1, 2025, Synthon Pharmaceuticals, Inc.).
What does the furosemide label say about tamsulosin?
Furosemide's label (effective September 30, 2025) and its 3 other brand-application labels do not name tamsulosin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Lasix), Validus Pharmaceuticals LLC, effective September 30, 2025 (SPL set 2c9b4d8f-0770-482d-a9e6-9c616a440b1a), via openFDA; the full label on DailyMed
What does the tamsulosin label say about furosemide?
Tamsulosin label, drug interactionsWhile furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride C max and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the tamsulosin hydrochloride capsules dosage [see Clinical Pharmacology (12.3) ].
Source: FDA drug label (Tamsulosin hydrochloride), Synthon Pharmaceuticals, Inc., effective December 1, 2025 (SPL set 13a5032d-0be1-4001-916e-459f0b1a051d), 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
| Furosemide | Tamsulosin | |
|---|---|---|
| Labeled for | Heart failure, High blood pressure, Edema (fluid retention) | Enlarged prostate (BPH) |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.490 per mL 20 mg/2 mL vial | $0.05 per capsule 0.4 mg capsule |
| 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