diflunisal
Brand names: Dolobid
Diflunisal is a medicine that can help with pain and swelling. It belongs to a class of drugs called NSAIDs.
Drug Pricing (NADAC)
Generic Price
$0.95/unit
Generic Available
Yes (3 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Diflunisal can help with mild to moderate pain.
Common side effects
Nausea, Vomiting, Upset stomach
Key warnings
NSAIDs like diflunisal can increase your risk of heart problems like heart attack and stroke, which can be deadly.
How It Works
Diflunisal reduces pain and swelling by blocking the production of certain chemicals in your body. These chemicals cause inflammation and pain. By blocking them, diflunisal helps to relieve your symptoms.
How to Take It
For mild to moderate pain, you might start with 1000 mg, then 500 mg every 12 hours. Some people may need 500 mg every 8 hours after the first dose. For arthritis, the usual dose is 500 mg to 1000 mg daily, divided into two doses. Swallow the tablets whole; do not crush or chew them.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. Taking diflunisal late in pregnancy may harm your baby. It is not known if diflunisal passes into breast milk, so talk to your doctor before breastfeeding.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store diflunisal at room temperature, away from moisture and heat.
Side Effects (from patient reports)
Based on 461 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 799 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
799
Death-Related Reports
66
Hospitalization Reports
236
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | NAUSEA | 66 |
| 2 | FATIGUE | 57 |
| 3 | PAIN | 50 |
| 4 | DRUG HYPERSENSITIVITY | 47 |
| 5 | HEADACHE | 45 |
| 6 | DRUG INEFFECTIVE | 44 |
| 7 | ARTHRALGIA | 43 |
| 8 | DIARRHOEA | 43 |
| 9 | FALL | 34 |
| 10 | DIZZINESS | 32 |
| 11 | MALAISE | 31 |
| 12 | PLATELET COUNT DECREASED | 31 |
| 13 | VOMITING | 28 |
| 14 | ANXIETY | 26 |
| 15 | CHRONIC KIDNEY DISEASE | 26 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
NSAIDs like diflunisal can increase your risk of heart problems like heart attack and stroke, which can be deadly. This risk is higher if you take it for a long time. You should not take diflunisal if you are having heart bypass surgery. NSAIDs also raise your risk of serious stomach problems like bleeding and ulcers, which can also be deadly. Older adults are at higher risk for these stomach problems.
Known Drug Interactions
Methotrexate NSAIDs have been reported to competitively inhibit methotrexate accumulation in rabbit kidney slices. This may indicate that they could enhance the toxicity of methotrexate. Caution should be used when NSAIDs are administered concomitantly with methotrexate.
Mechanism: Diflunisal can prevent your kidneys from clearing methotrexate out of your system, which can lead to toxic levels of the drug in your blood. This makes the side effects of methotrexate much more dangerous.
What to do: Be very careful when using these drugs together and make sure your doctor monitors your health and blood work closely.
Cyclosporine Administration of non-steroidal anti-inflammatory drugs concomitantly with cyclosporine has been associated with an increase in cyclosporine-induced toxicity, possibly due to decreased synthesis of renal prostacyclin. NSAIDs should be used with caution in patients taking cyclosporine, and renal function should be carefully monitored.
Mechanism: Diflunisal may reduce protective substances in the kidneys, which can increase the risk of harmful side effects from cyclosporine. This happens because the kidneys cannot process the drugs as safely.
What to do: Use these medications together with caution. Your doctor should monitor your kidney function closely.
NSAIDs and Salicylates Clinical Impact: Concomitant use of Celecoxib with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy [ see Warnings and Precautions (5.2) ] .
Mechanism: Both drugs are similar types of pain relievers that can harm the stomach lining. Taking them together increases the risk of stomach problems without helping your pain any more than one drug alone.
What to do: You should avoid taking these two medications together to prevent serious stomach or intestinal issues.
NSAIDs and Salicylates Clinical Impact: Concomitant use of indomethacin with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy [ see Warnings and Precautions ( 5.2 ) ] . Combined use with diflunisal may be particularly hazardous because diflunisal causes significantly higher plasma levels of indomethacin [ see Clinical Pharmacology ( 12.3 ) ]. In some patients, combined use of indomethacin and diflunisal has been associated with fatal gastrointestinal hemorrhage.
Mechanism: Diflunisal causes the body to have much higher levels of indomethacin in the blood. This increases the risk of serious stomach bleeding without making the medicine work any better.
What to do: Avoid taking these two medicines together. This combination is dangerous and has been linked to fatal bleeding in the stomach.
NSAIDs and Salicylates Clinical Impact: Concomitant use of mefenamic acid with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy (see Warnings ; Gastrointestinal Bleeding, Ulceration and Perforation ).
Mechanism: Taking these two drugs together increases the risk of stomach bleeding and ulcers without providing extra relief. Both drugs are similar and can irritate the lining of your digestive system.
What to do: Avoid taking these two medications at the same time. Your doctor should help you choose just one of these drugs to manage your symptoms safely.
Common Questions
Can I take diflunisal with other pain relievers?
Can I drink alcohol while taking diflunisal?
How long does it take for diflunisal to work?
Can diflunisal affect my blood pressure?
Can diflunisal cause kidney problems?
Can I take diflunisal if I am allergic to aspirin?
Does diflunisal interact with any other medications?
Can diflunisal cause skin reactions?
What should I do if I experience side effects from diflunisal?
Can I drive or operate machinery while taking diflunisal?
What are the common side effects of diflunisal?
Does diflunisal interact with other medications?
What drug class is diflunisal?
Is diflunisal safe during pregnancy?
Related Medications in Nonsteroidal Anti-Inflammatory Drug (NSAID)
Other drugs grouped near diflunisal — same-class peers and common alternatives.
abatacept
Orencia
Orencia is a medicine that helps to reduce inflammation.
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acetaminophen
Tylenol
Acetaminophen (Tylenol) is a medicine that can relieve pain and reduce fever.
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acetaminophen/hydrocodone
Vicodin, Norco
This medicine contains acetaminophen and hydrocodone.
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acetaminophen/oxycodone
Percocet
Percocet is a strong pain medicine.
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adalimumab
Humira
Idacio is a medicine that blocks a protein called TNF.
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What the FDA Data Shows for diflunisal
The FDA label for diflunisal (sold under brand names such as Dolobid) classifies it as a prescription-only medication in the Nonsteroidal Anti-Inflammatory Drug (NSAID) class. Diflunisal can help with mild to moderate pain. Official labeling lists 14 commonly reported side effects, including Nausea, Vomiting, Upset stomach.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 461 voluntary reports. The database also lists 17 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.95.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 10, 2024
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages