Prescription medication · Nonsteroidal Anti-Inflammatory Drug (NSAID)
diflunisal
Also sold as Dolobid. Diflunisal can help with mild to moderate pain.
Data updated 2026-05-15
- 799
- FDA reportsRarely reported
- 17
- InteractionsSeveral interactions
- $0.95
- Generic price (NADAC)
What the data shows
diflunisal (Dolobid) is a prescription Nonsteroidal Anti-Inflammatory Drug (NSAID), among the least-reported drugs the FDA tracks (799 FDA reports), with 17 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
diflunisal (Dolobid) is a prescription Nonsteroidal Anti-Inflammatory Drug (NSAID). Diflunisal can help with mild to moderate pain.
Diflunisal is a medicine that can help with pain and swelling. It belongs to a class of drugs called NSAIDs.
Verify with FDA → · CMS NADAC pricing →
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.
The sections below are summarized in plain English from diflunisal's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
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.
This is a plain-language summary of diflunisal's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
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.
This is a plain-language summary of diflunisal's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
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.
This is a plain-language summary of diflunisal's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store diflunisal at room temperature, away from moisture and heat.
Side Effects (from patient reports)
Based on 799 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for diflunisal, by number of reports
- Feeling sick to your stomach
Feeling sick to your stomach
66 reports
- Feeling very tired
Feeling very tired
57 reports
- Discomfort or aching
Discomfort or aching
50 reports
- Allergic reaction to the medicine
Allergic reaction to the medicine
47 reports
- Pain in your head
Pain in your head
45 reports
- Joint pain
Joint pain
43 reports
- Loose, watery stools
Loose, watery stools
43 reports
- Accidentally losing your balance
Accidentally losing your balance
34 reports
- Feeling lightheaded or unsteady
Feeling lightheaded or unsteady
32 reports
- General feeling of discomfort or illness
General feeling of discomfort or illness
31 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for diflunisal each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where diflunisal sits
diflunisal has more FDA adverse-event reports than 5% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is diflunisal; the line is the median (50th percentile).
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
Reports Mentioning Death
66
8.3% of reports — not proof of cause
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 |
| 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 |
| 16 | INJECTION SITE PAIN | 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.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
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?
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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 799 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.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
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