Diflunisal

Introduction

Written by Patricia Weiser, PharmD
Medically reviewed by Alex Brewer, PharmD, MBA
Updated on September 8, 2023

Diflunisal (dye FLOO ni sal) is a generic medication prescribed for pain and certain types of arthritis. Diflunisal belongs to a group of drugs called nonsteroidal anti-inflammatory drugs.

The Food and Drug Administration (FDA) has approved diflunisal to treat mild to moderate pain in adults and children ages 12 years and older. The FDA has also approved diflunisal to treat the symptoms of:

• osteoarthritis
• rheumatoid arthritis

Boxed warnings

Diflunisal has boxed warnings about the risks of serious heart and blood vessel events and serious digestive events. Boxed warnings are the most serious warnings from the FDA.

For details, see the “Interactions and warnings for diflunisal” section.

Common questions about diflunisal

Below you’ll find answers to a few commonly asked questions about diflunisal.

What brand names are available for diflunisal?

Currently, no brand-name versions of diflunisal exist. In the past, the brand-name drug Dolobid was available. But this product was discontinued.

Diflunisal is a generic drug. A generic medication is an identical copy of the active drug in a brand-name medication. (An active drug is the ingredient that makes a medication work.) Generic drugs are believed to be as effective and safe as brand-name drugs. And generic drugs usually cost less compared with brand-name drugs.

Talk with your doctor or pharmacist if you have questions about brand-name versus generic drugs.

How does diflunisal work? And how long does it take to start working?

Diflunisal’s mechanism of action (how it works) is to block the formation of prostaglandins (hormone-like compounds) in the body. When the body makes prostaglandins, symptoms of pain and inflammation occur. By limiting the amount of prostaglandins produced, diflunisal reduces symptoms of pain and inflammation.

Diflunisal begins working shortly after you take a dose. The drug reaches its maximum effect in the body within 3 hours after taking the medication. It may take a few days of continued treatment with diflunisal to notice your symptoms easing.

If you’d like to know more about how diflunisal works, talk with your doctor or pharmacist.

Can I take diflunisal with aspirin?

Possibly, but the combination can increase the risk of side effects, including serious digestive events.* Both aspirin and diflunisal belong to the same group of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). Both drugs may cause similar side effects. In general, a person should only take one NSAID drug at a time.

You should only take aspirin while taking diflunisal if your doctor specifically instructs doing so. For instance, doctors may tell some people to take a low dose of aspirin once daily. Generally, you should not take higher doses of aspirin while taking diflunisal.

If you’d like to know more about taking other medications with diflunisal, talk with your doctor or pharmacist.

* Diflunisal has boxed warnings about the risks of serious heart and blood vessel events and serious digestive events. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). For details, see the “Interactions and warnings for diflunisal” section.

Is diflunisal similar to ibuprofen?

Yes, ibuprofen (Advil, Motrin) and diflunisal are both NSAIDs. They help ease pain and treat the symptoms of arthritis. Both drugs may cause similar side effects.

The main difference between ibuprofen and diflunisal is their availability. Ibuprofen can be purchased over the counter (OTC), and is also available in a prescription-only strength. On the other hand, diflunisal requires a prescription (Rx) and is not available OTC at any strength.

If you’d like to learn more about the similarities or differences between diflunisal and other NSAIDs, talk with your doctor or pharmacist.

Side effects of diflunisal

Diflunisal may cause mild or serious side effects. More common mild side effects of diflunisal and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about diflunisal’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for diflunisal listed in the “Resources” section.

Mild side effects

More common mild side effects of diflunisal are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about diflunisal’s side effects, refer to the prescribing information for diflunisal listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Diflunisal oral tablet’s mild side effects include:

• headache
• nausea
• upset stomach
• diarrhea
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for diflunisal” section.

Serious side effects

Serious side effects of diflunisal are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about diflunisal’s side effects, refer to the prescribing information for diflunisal listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, diflunisal’s serious side effects include:

• increased blood pressure, which may cause or worsen high blood pressure
• swelling due to fluid buildup in your body
• kidney problems
• liver problems
• increased risk of bleeding
• hearing problems, such as tinnitus (ringing in the ears)
• blood disorders, such as anemia (low red blood cell count)
• heart failure
• boxed warnings: risks of serious heart and blood vessel events and serious digestive events*
• severe allergic reaction, including serious skin reactions*

* For details about this side effect, see the “Interactions and warnings for diflunisal” section.

Interactions and warnings for diflunisal

Below, you’ll find information about diflunisal’s possible interactions and warnings.

Interactions of diflunisal

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take diflunisal, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for diflunisal” section below.

Warnings for diflunisal

Some people should not take diflunisal, and others should take it cautiously.

Boxed warnings

Diflunisal has boxed warnings about the risks of serious heart and blood vessel events and serious digestive events. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA).

To learn more about these warnings, read below. You can also talk with your doctor or pharmacist.

Risk of serious heart and blood vessel events. Taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as diflunisal, increases the risk of serious heart and blood vessel events. These include heart attack or stroke. Any length of treatment with diflunisal carries this risk. But studies show that long-term and high dose treatment is more commonly associated with a higher risk of these side effects.

Your risk may also be higher if you already have heart and blood vessel problems, such as high blood pressure.

Heart attack symptoms may include:

• pain or pressure in your chest
• sweating
• shortness of breath
• fatigue (low energy)
• discomfort in your shoulder, arm, neck, or jaw

Symptoms of stroke may include:

• facial drooping
• weakness in an arm
• trouble speaking

If you experience these symptoms, seek urgent medical care or call 911 or your local emergency number. If you have concerns about your risk of serious heart and blood vessel events, tell your doctor. They’ll likely recommend taking diflunisal for the shortest length of time possible.

Risk of serious digestive events. Taking NSAIDs such as diflunisal may damage the lining of the digestive tract. This may cause serious digestive problems, such as bleeding, ulcers (sores), or perforation (holes) in the stomach or intestines. These side effects were rarely reported in studies of diflunisal.

Older adults (ages 65 years and older) and people with a history of certain digestive problems may have a higher risk of this side effect.

Symptoms of bleeding, ulcers, or perforation in the digestive tract may include:

• intense pain in your abdomen
• vomiting blood
• bloody or tar-like bowel movements

If you experience these symptoms, seek urgent medical care or call 911 or your local emergency number. If you have concerns about your risk of serious digestive events, tell your doctor. They’ll likely recommend taking diflunisal for the shortest length of time possible.

Other warnings

Diflunisal could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether diflunisal is a safe option for you.

Ask your doctor about specific warnings for diflunisal, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Diflunisal can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to diflunisal or any of its ingredients, your doctor will likely not prescribe diflunisal. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to diflunisal, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of diflunisal

You should not take more diflunisal than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much diflunisal, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and diflunisal

Information about diflunisal and pregnancy and breastfeeding is described below.

Diflunisal and pregnancy

Diflunisal should not be taken after Week 30 of pregnancy. (Pregnancy is usually 40 weeks long.) Doctors usually avoid prescribing them between Weeks 20–30 of a pregnancy, except in special cases.

If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. Your doctor may suggest birth control options to use during treatment with diflunisal.

Diflunisal and breastfeeding

Diflunisal should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with diflunisal or discuss other medication options during breastfeeding.

Uses of diflunisal

The Food and Drug Administration (FDA) approves prescription drugs such as diflunisal for certain conditions. Approved uses for diflunisal are described below.

Use for pain

Doctors may prescribe diflunisal oral tablet for easing mild to moderate pain. It’s used for this purpose in adults and children ages 12 years and older. It’s usually prescribed as a short-term treatment.

With mild to moderate pain, a person has discomfort that somewhat interferes with their daily activities. These may include work, chores, or sleep.

Use for certain forms of arthritis

Doctors may prescribe diflunisal oral tablet for treating the symptoms of certain types of arthritis. It may be prescribed as a short-term or long-term treatment.

Specifically, the FDA has also approved diflunisal to treat the symptoms of:

• osteoarthritis
• rheumatoid arthritis

The drug is prescribed for this purpose in adults and children ages 12 years and older. But these conditions do not usually occur in children.

With osteoarthritis, wear and tear of the joints can lead to joint pain and inflammation. Symptoms may also include changes in your bones and joints, such as bone spurs or crepitus (creaking sounds when you bend or stretch).

With rheumatoid arthritis, the immune system mistakenly attacks the joints, leading to damage and inflammation. Symptoms may include:

• joint pain, stiffness, or swelling
• changes in how the affected joint looks and functions
• fever

What to ask your doctor

Let your doctor know if you have questions about diflunisal or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Is diflunisal a stronger pain reliever than over-the-counter pain relievers?
• What steps can I take to help prevent digestive side effects of diflunisal?
• What other treatment options are safe to take with diflunisal to help relieve my symptoms?

Resources

• Diflunisal tablets, USP. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/2043bab8-87c9-45ce-88c7-383f0d4c4b64/spl-doc
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.