What the FDA labels say about taking them together
Diflunisal and furosemide
Diflunisal's FDA label of August 4, 2026 names furosemide in its drug interactions section; furosemide's label does not name diflunisal itself but warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)). The diflunisal label: “Diuretics Clinical studies, as well as postmarketing observations, have shown that diflunisal can reduce the natriuretic effect of furosemide and thiazides in some patients.”
Check it at the source: the diflunisal FDA label on DailyMed (effective August 4, 2026, Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.); the furosemide FDA label on DailyMed (effective September 30, 2025, Validus Pharmaceuticals LLC).
What does the diflunisal label say about furosemide?
Diflunisal label, drug interactionsDiuretics Clinical studies, as well as postmarketing observations, have shown that diflunisal can reduce the natriuretic effect of furosemide and thiazides in some patients.
Source: FDA drug label (diflunisal), Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc., effective August 4, 2026 (SPL set 666f89b4-fd81-420a-a390-eb1cd4014f61), via openFDA; the full label on DailyMed
What does the furosemide label say about diflunisal?
Furosemide's label does not name diflunisal itself; it warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)):
Furosemide label, drug interactionsThere are case reports of patients who developed increased BUN, serum creatinine and serum potassium levels, and weight gain when furosemide was used in conjunction with NSAIDs.
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
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
| Diflunisal | Furosemide | |
|---|---|---|
| Labeled for | Pain, Osteoarthritis, Rheumatoid arthritis | Heart failure, High blood pressure, Edema (fluid retention) |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $1.06 per tablet 500 mg tablet | $0.490 per mL 20 mg/2 mL vial |
| Shortage now | No current entry | In shortage |
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