What the label lists and what reports show
Diflunisal side effects
Diflunisal's FDA label lists its adverse reactions in its own words. FAERS holds 806 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nausea (66 reports).
- Generic listed
- Boxed warning
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 FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of NSAIDs?NSAIDs can cause serious side effects, including: See “What is the most important information I should know about medicines called Nonsteroidal Anti-inflammatory Drugs (NSAIDs)? • new or worse high blood pressure • heart failure • liver problems including liver failure • kidney problems including kidney failure • low red blood cells (anemia) • life-threatening skin reactions • life threatening allergic reactions • Other side effects of NSAIDs include: stomach pain, constipation, diarrhea, gas, heartburn, nausea, vomiting, and dizziness. […]
Source: FDA drug label, 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 label list?
From the label: adverse reactionsThe adverse reactions observed in controlled clinical trials encompass observations in 2,427 patients. Listed below are the adverse reactions reported in the 1,314 of these patients who received treatment in studies of two weeks or longer. Five hundred thirteen patients were treated for at least 24 weeks, 255 patients were treated for at least 48 weeks, and 46 patients were treated for 96 weeks. In general, the adverse reactions listed below were 2 to 14 times less frequent in the 1,113 patients who received short-term treatment for mild to moderate pain. Incidence Greater Than 1% Gastrointestinal The most frequent types of adverse reactions occurring with diflunisal are gastrointestinal: these include nausea*, vomiting, dyspepsia*, gastrointestinal pain*, diarrhea*, constipation, and flatulence. Psychiatric Somnolence, insomnia. Central Nervous System Dizziness. …
Source: FDA drug label, 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 do FAERS reports show?
806 reports list diflunisal among the medicines taken, each a report of something that happened, not proof the medicine caused it; 66 are coded as a death and 239 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 11 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Diflunisal: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions