Diflunisal

(die-flu-nih-sal)

Trade/other name(s): Dolobid

Why would this drug be used?

Diflunisal may be used to treat mild to moderate pain from cancer, surgery, or other causes. For severe pain, it is more helpful when used with other pain-relieving drugs. It is also used to reduce inflammation and for other purposes.

How does this drug work?

Diflunisal is a non-opioid pain medicine, meaning that it is not in the same family as morphine or codeine. It belongs to the general group of drugs called non-steroidal anti-inflammatory drugs (NSAIDs). How it works is not fully understood, but it helps block the body from making prostaglandins. (Prostaglandins are substances made by most of the cells in the body. They have a role in many body functions, including pain and inflammation.) Diflunisa helps prevent pain receptors from passing pain messages to the brain. It also helps reduce inflammation.

Before taking this medicine

Tell your doctor…

• If you are allergic to anything, including medicines, dyes, additives, or foods.
• About any reactions you have had when taking aspirin or other non-steroidal anti-inflammatory medicines in the past. If you have had problems with any of these medicines, you are more likely to have problems taking diflunisal.
• If you have ever had any medical conditions such as asthma, nasal polyps, allergies, high blood pressure, kidney disease, liver disease (including hepatitis), stroke, high cholesterol, or heart disease. These conditions increase the risk of serious side effects from or reactions to diflunisal, and you may need a different medicine. If you take the drug, you may need to be watched more closely during treatment.
• If you have congestive heart failure or fluid retention (swelling, usually of the legs and feet). Diflunisal may worsen this problem.
• If you are taking blood pressure medicines. Diflunisal may cause some blood pressure medicines to stop working properly. In some cases, the combination of medicines may damage the kidneys.
• If you have ever had stomach or intestinal ulcers, especially if you had bleeding. Diflunisal can worsen these problems or make them come back.
• If you have hemophilia or any other bleeding problem, or if you are taking blood thinners such as warfarin or heparin. Diflunisal can increase your risk of bleeding from the stomach or intestine.
• If you are pregnant or trying to get pregnant. Taking diflunisal, especially later in pregnancy, can harm the baby.
• If you are breast-feeding. Diflunisal is passed into breast milk and may affect the baby.
• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

If you take diflunisal while you are taking lithium, your lithium level may go up. This can increase your risk of toxic effects from lithium. You may need more frequent monitoring of lithium levels while on diflunisal.

Taking diflunisal while using "blood thinners" (such as warfarin and heparin) can increase your risk of serious bleeding.

Taking diflunisal and acetaminophen (Tylenol) may cause acetaminophen levels in the body to reach higher levels. This can worsen the risk that acetaminophen will damage your liver or cause other serious effects.

Taking diflunisal while taking indomethacin or other non-steroidal anti-inflammatory drugs (such as ibuprofen, naproxen, ketoprofen, and others) can greatly increase the risk of harm to the stomach, intestines, or kidneys.

Alcohol may increase your risk of stomach irritation or bleeding, as may aspirin. Steroids that are taken by mouth, such as prednisone, prednisolone, hydrocortisone, betamethasone, budesonide, triamcinolone, can also increase this risk.

Medicines for high blood pressure, such as diuretics (water pills) and angiotensin-converting enzyme (ACE) inhibitors (such as captopril, lisinopril, enalapril, benazepril, and others) may not work as well if taken during treatment with diflunisal. You may need more frequent blood pressure checks and possibly a change of medicines.

Methotrexate may have more toxic effects if diflunisal is taken during the same time.

Frequent use of antacids may lower the level of diflunisal in your blood, so that it doesn't work as well.

Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Diflunisal is a pill that can be taken by mouth with water, milk, or food. It should be swallowed whole, and not chewed, crushed, or broken. Your doctor may tell you to take a higher dose for your first dose, called a "loading dose," to get the drug level higher in your body and allow it to start working sooner. After the first dose, the drug is usually taken every 8 to 12 hours. It may take a day or two to get the full benefit of this drug.

Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you.

Keep the medicine in a tightly closed container away from heat and moisture and out of the reach of children and pets.

Precautions

Avoid taking aspirin or other anti-inflammatory drugs such as ibuprofen with diflunisal. They may increase the risk of bleeding or stomach irritation. Aspirin and ibuprofen are often added to other medicines. Read the ingredient list on any remedies for headache, sinus, cold or flu before taking them, or check with your pharmacist.

Avoid diflunisal if you have any ulcers in the stomach or intestine. Diflunisal can cause severe bleeding or holes in the intestine.

If you have ever had trouble breathing, rash, itching, or swelling in the mouth or throat after taking aspirin or other anti-inflammatory drugs, do not take diflunisal.

If your blood counts are low due to chemotherapy or radiation, check with your doctor or nurse before taking diflunisal. It may increase your chance of bleeding.

Call your doctor or nurse right away if you are vomiting blood or a coffee-ground material, notice blood in your stools, or if your stools appear black and tarry. Talk to your doctor if you have pain in your belly or severe indigestion. Stop taking diflunisal until after you talk with your doctor.

Diflunisal must be stopped a few days before any type of surgery. Make sure you tell your doctor or dentist at least a week before surgery if you are taking diflunisal.

Your doctor may want to check your lab work and blood pressure more often if you are taking diflunisal for more than a few weeks. This is to help find problems early, before they worsen.

Call your doctor or nurse right away if your vision is blurred, you don't see colors well, or if you see spots in front of your eyes. Stop taking diflunisal until you talk to your doctor or nurse.

If you notice sores in your mouth or any type of rash or blistering, especially if you also have a fever and feel sick, stop the diflunisal and call your doctor right away.

Diflunisal can cause you to retain fluids and make heart failure worse. If you have unexplained weight gain or swelling, stop the diflunisal and call your doctor.

Rarely, diflunisal can cause damage to the liver. If you notice nausea, tiredness, itching, tenderness below the right side of your rib cage, flu-like symptoms, or yellowing of the skin or eyes, stop the medicine and call your doctor or nurse right away.

Diflunisal can increase your risk of heart attack and stroke. If you develop shortness of breath, chest pain, weakness in one part or on one side of the body, or slurred speech, get help right away.

If you have signs of an allergic reaction such as trouble breathing, fast heartbeat, sudden faintness or dizziness, itchy welts on the skin, or swelling of your mouth, face, or throat, get emergency help.

Smoking or drinking alcohol increases your risk of bleeding from the stomach or intestine.

Most cancer pain can be controlled. If you are taking diflunisal for cancer pain, keep your doctor or nurse informed about how well your pain medicines are working and any side effects you are having. Your cancer team may need to adjust your medicines several times before they find the medicines that work best for you.

If your doctor prescribes another medicine for pain, ask your doctor or nurse whether you should continue taking diflunisal along with the new medicine. Severe pain usually requires more than one type of medicine to control it.

If you have chronic cancer pain, take your pain medicines on a regular schedule to keep it from worsening. If you wait until the pain is bad, it takes more medicine to get it under control. If pain gets bad between doses, talk to your cancer team about changing your medicine or adding an extra one for "breakthrough" pain.

Do not give diflunisal, aspirin, or other salicylates to a child or teen with a fever or other symptoms of viral infection without first discussing it with the child's doctor. It may cause a serious illness called Reye's syndrome in children and teens with viral infections, especially flu and chickenpox.

If you think that you or someone else may have taken an overdose of diflunisal, get emergency help right away. Symptoms of overdose may include drowsiness, nausea, vomiting, diarrhea, fast breathing, fast heartbeat, sweating, ringing in the ears, confusion, stupor, and coma.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.

Common

• nausea
• stomach pain*
• upset stomach
• diarrhea
• headache

Less common

• abnormal blood tests which suggest that the drug is affecting the liver (Your doctor will discuss the importance of this finding, if any)
• rash
• tiredness
• gas
• dizziness
• increase in blood pressure*
• vomiting
• constipation

Rare

• swelling of arms, hands, legs, or feet*
• fluid retention with weight gain*
• problems with vision*
• ringing in the ears
• bleeding in the stomach or intestines (risk greater with longer use)*
• peptic (stomach) ulcers*
• damage to kidneys (usually improves when medicine is stopped)
• damage to liver, which can cause yellow skin or eyes, pain in the upper abdomen*
• anemia*
• heart attack*
• stroke*
• serious skin rash with itching, blistering, feeling sick, fever*
• worsening of asthma symptoms*
• allergic reaction with trouble breathing, skin welts, itching, feeling faint, or swelling of the face, mouth, or throat*
• difficult or painful urination

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984).

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.