What the FDA labels say about taking them together
Diclofenac and diflunisal
Diclofenac's FDA label (Licart) of April 2, 2026 names diflunisal in its drug interactions section; diflunisal's label does not name diclofenac itself but warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)). The diclofenac label: “Concomitant use of diclofenac with other NSAIDs or salicylates increases the risk of GI toxicity, with little or no increase in efficacy.”
Check it at the source: the diclofenac FDA label on DailyMed (effective February 11, 2025, Haleon US Holdings LLC); the diflunisal FDA label on DailyMed (effective August 4, 2026, Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.).
What does the diclofenac label say about diflunisal?
Licart label (IBSA Pharma Inc., April 2, 2026), drug interactionsNSAIDs and Salicylates Clinical Impact: Concomitant use of diclofenac with other NSAIDs or salicylates (…) increases the risk of GI toxicity, with little or no increase in efficacy. Intervention: The concomitant use of diclofenac with other NSAIDs or salicylates is not recommended.
Zipsor label (Assertio Specialty Pharmaceuticals LLC, March 1, 2026), drug interactionsNSAIDs and Salicylates Clinical Impact: Concomitant use of diclofenac with other NSAIDs or salicylates (…) increases the risk of GI toxicity, with little or no increase in efficacy [ see Warnings and Precautions () ]. Intervention: The concomitant use of diclofenac with other NSAIDs or salicylates is not recommended.
Source: FDA drug label (Licart, NDA206976), IBSA Pharma Inc., effective April 2, 2026 (SPL set 851c8b39-6056-4bbc-812e-b9b13977c1ac), via openFDA
Source: FDA drug label (Zipsor, NDA022202), Assertio Specialty Pharmaceuticals LLC, effective March 1, 2026 (SPL set ed2a8868-78eb-47b8-8f46-0f70e2891e07), via openFDA
Source: FDA drug label (Voltaren Arthritis Pain), Haleon US Holdings LLC, effective February 11, 2025 (SPL set 30a94282-0892-442a-aa10-6525cbd4fe88), via openFDA; the full label on DailyMed
What does the diflunisal label say about diclofenac?
Diflunisal's label does not name diclofenac itself; it warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)):
Diflunisal label, boxed warningGastrointestinal Risk NSAIDs cause an increased risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal.
Diflunisal label, warningsGastrointestinal Effects – Risk of Ulceration, Bleeding and Perforation NSAIDs, including diflunisal tablets, can cause serious gastrointestinal (GI) adverse events including inflammation, bleeding, ulceration, and perforation of the stomach, small intestine, or large intestine, which can be fatal.
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
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
| Diclofenac | Diflunisal | |
|---|---|---|
| Labeled for | Pain, Osteoarthritis, Rheumatoid arthritis, Migraine | Pain, Osteoarthritis, Rheumatoid arthritis |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0619 per tablet 75 mg tablet | $1.06 per tablet 500 mg tablet |
| Shortage now | A presentation being discontinued | 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