Diflunisal is used to relieve mild to moderate pain from various conditions. It also reduces pain, swelling, and joint stiffness caused by arthritis. Reducing these symptoms helps you do more of your normal daily activities. This medication is known as a nonsteroidal anti-inflammatory drug (NSAID).

This medication is not recommended for use in children under 12 years of age.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used for gout attacks.

Read the Medication Guide provided by your pharmacist before you start using diflunisal and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with a full glass of water (8 ounces or 240 milliliters) unless your doctor directs you otherwise. Do not lie down for at least 10 minutes after taking this drug. Take this medication with food/milk or right after meals to prevent stomach upset.

Swallow this medication whole. Do not crush or chew the tablets. Doing so may increase side effects.

The dosage is based on your medical condition and response to treatment. Do not take more than 1,500 milligrams per day. To minimize side effect risks (such as stomach bleeding), use this medication at the lowest effective dose for the shortest possible length of time. Do not increase your dose or take it more often than prescribed. For ongoing conditions such as arthritis, keep taking it as directed by your doctor. Discuss the risks and benefits with your doctor or pharmacist.

In certain conditions (such as arthritis), it may take up to 2 weeks of regular use before the full benefits of this drug take effect.

If you are taking this drug on an "as needed" basis (not on a regular schedule), remember that pain medications work best if they are used as the first signs of pain occur. If you wait until the pain has significantly worsened, the medicine may not work as well.

Tell your doctor if your condition gets worse.

See also Warning section.

Upset stomach, heartburn, headache, tiredness, drowsiness, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• vision changes
• hearing changes (such as ringing in the ears)
• mental/mood changes (such as confusion, hallucinations)
• fast/pounding heartbeat
• fainting
• difficult/painful swallowing
• signs of kidney problems (such as change in the amount of urine)
• easy bruising/bleeding
• symptoms of heart failure (such as swelling ankles/feet, unusual tiredness, unusual/sudden weight gain)

This drug may rarely cause serious (possibly fatal) liver disease. Get medical help right away if you have any symptoms of liver damage, including:

• nausea/vomiting that doesn't stop
• yellowing eyes/skin
• dark urine
• unusual/extreme tiredness
• stomach/abdominal pain

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• fever
• swollen lymph nodes
• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

See also Warning section.

Before taking diflunisal, tell your doctor or pharmacist if you are allergic to it; or to aspirin or other salicylates (such as choline salicylate), or other NSAIDs (such as ibuprofen, naproxen, celecoxib); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• asthma (including a history of worsening breathing after taking aspirin or other NSAIDs)
• liver disease
• diabetes
• stomach/intestine/esophagus problems (such as bleeding, ulcers)
• heart disease (such as history of heart attack)
• stroke
• high blood pressure
• swelling (edema, fluid retention)
• blood disorders (such as anemia)
• bleeding or clotting problems
• growths in the nose (nasal polyps)

Kidney problems can sometimes occur with the use of NSAID medications, including diflunisal. Problems are more likely to occur if you are dehydrated, have heart failure or kidney disease, are an older adult, or if you take certain medications (see also Drug Interactions section). Drink plenty of fluids as directed by your doctor to prevent dehydration and tell your doctor right away if you have a change in the amount of urine.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Talk to your doctor if you are using marijuana (cannabis).

This medicine may cause stomach bleeding. Daily use of alcohol and tobacco may increase your risk for stomach bleeding, especially when combined with this medicine. Limit alcohol and stop smoking. Consult your doctor or pharmacist for more information.

Older adults may be more sensitive to the side effects of this drug, especially stomach/intestinal bleeding and kidney problems.

Since diflunisal is related to aspirin, children and teenagers younger than 18 years should not take diflunisal if they have chickenpox, influenza, or any undiagnosed illness without first consulting a doctor about Reye's syndrome, a rare but serious illness.

Before using this medication, women of childbearing age should talk with their doctor(s) about the benefits and risks. Tell your doctor if you are pregnant or if you plan to become pregnant. This medication may harm an unborn baby and cause problems with normal labor/delivery. It is not recommended for use in pregnancy from 20 weeks until delivery. If your doctor decides that you need to use this medication between 20 and 30 weeks of pregnancy, you should use the lowest effective dose for the shortest possible time. You should not use this medication after 30 weeks of pregnancy.

This drug passes into breast milk. Breastfeeding is not recommended while using this drug. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• aliskiren
• ACE inhibitors (such as captopril, lisinopril)
• angiotensin II receptor blockers (such as losartan, valsartan)
• antacids (regular use)
• cidofovir
• corticosteroids (such as prednisone)
• digoxin
• live influenza vaccine
• lithium
• methotrexate
• pemetrexed
• probenecid
• "water pills" (diuretics such as furosemide, hydrochlorothiazide, triamterene)

This medication may increase the risk of bleeding when taken with other drugs that also may cause bleeding. Examples include anti-platelet drugs such as clopidogrel, "blood thinners" such as dabigatran/enoxaparin/warfarin, among others.

Check all prescription and nonprescription medicine labels carefully since many contain pain relievers/fever reducers (NSAIDs such as aspirin, ibuprofen, indomethacin, ketorolac or naproxen) which if taken together with diflunisal may increase your risk for side effects. However, if your doctor has told you to take low-dose aspirin to prevent heart attack or stroke (usually 81-162 milligrams a day), you should keep taking the aspirin unless your doctor tells you not to. Ask your doctor or pharmacist for more details.

This medication may interfere with certain lab tests, possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include severe stomach pain, vomit that looks like coffee grounds, extreme drowsiness, fast breathing, confusion, loss of consciousness.

Do not share this medication with others.

Lab and/or medical tests (such as complete blood count, liver/kidney function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Non-drug treatment for arthritis that is approved by your doctor (such as weight loss if needed, strengthening and conditioning exercises) may help improve your flexibility, range of motion, and joint function. Consult your doctor for specific instructions.

If you are prescribed this drug on a regular schedule (not just "as needed") and you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.