Relafen (Nabumetone) Side Effects

Relafen (nabumetone) is a prescription nonsteroidal anti-inflammatory drug (NSAID). Healthcare providers prescribe it primarily for inflammation and pain related to arthritis—specifically osteoarthritis and rheumatoid arthritis. As with other NSAIDs, it’s possible to experience side effects while taking Relafen. 

Unrecognizable Woman Pours Pills into Hand from Prescription Bottle

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Common Side Effects

Some of the most common side effects of taking Relafen include:

  • Gastrointestinal problems, including diarrhea, constipation, gas, and bloating
  • Heartburn
  • Headache
  • Dizziness
  • Mouth sores
  • Dry mouth
  • Trouble sleeping
  • Nervousness 
  • Tinnitus (a ringing or roaring sound in the ears)
  • Increased sweating 

Even though most of these side effects are common and not necessarily life-threatening, you should talk to your healthcare provider if they occur. Also tell your practitioner about side effects that don’t go away.

Serious Side Effects

The following less-common but serious side effects can also occur when taking Relafen:

  • Fatigue
  • Weight gain
  • Swelling
  • Breathing troubles
  • Appetite changes
  • Jaundice
  • Nausea
  • Flu-like symptoms, including fever
  • Rash and other skin changes like blisters and hives
  • Rapid heartbeat
  • Blood or discoloration in the urine
  • Back pain
  • High blood pressure
  • Stomach ulcers 
  • Blood in the stool
  • Vomit resembling coffee grounds, which may point to bleeding in the stomach 

If you experience these side effects, talk to your practitioner right away. Trouble breathing is an especially concerning symptom and requires immediate medical attention.

When to Call Your Healthcare Provider

If you experience any side effects that don’t go away on their own, call your healthcare provider, who may prescribe a different medication. If you are taking any other drugs and don’t know whether they’re safe to take with Relafen, ask your practitioner or pharmacist for advice.

If you suspect you’re having an allergic reaction to the medication, get emergency medical help. Signs of an allergic reaction include:

  • Trouble breathing
  • Difficulty swallowing
  • Rash that itches
  • Swelling of the mouth, throat, and lips

People who experience stroke or heart attack symptoms while taking Relafen should also seek emergency medical attention. Possible signs of a heart attack include:

  • Shortness of breath
  • Chest pain
  • Pain in the jaw or arm

Possible symptoms of a stroke include: 

  • Difficulty speaking, slurring words
  • Balance problems 
  • Drooping face 
  • Weakness on one side of the body


Here's some information about warnings and interactions that you should keep in mind when taking Relafen:

  • Allergies: Some people are allergic to Relafen’s ingredients, as well as aspirin or other NSAIDs. Tell your healthcare provider if you have allergies to these or other drugs.
  • Asthma: Serious asthma attacks may occur in people taking Relafen.
  • Pregnancy: Inform your practitioner if you are pregnant or may become pregnant as Relafen can cause complications in late pregnancy.
  • Surgery: Because Relafen may cause blood clotting, your surgeon, including your dental surgeon, will need to be aware that you are taking this drug.
  • Sun Sensitivity: Always wear sun protection to shield your skin from harmful ultraviolet (UV) rays, especially when taking a drug like Relafen, which may make your skin more sensitive to sunlight.
  • Liver: In rare cases, Relafen may cause liver toxicity in patients with impaired liver function.
  • Kidneys: People with existing kidney disease may be at higher risk for rare kidney-related side effects, such as renal failure.

Black Box Warning

Some people have a higher risk of gastrointestinal bleeding when taking NSAIDs like Relafen. People at risk of this side effect include:

  • Older adults
  • Those taking NSAIDs for a prolonged period
  • People who drink alcohol in excess 
  • People with a history of ulcers or digestion issues 

Relafen, like other NSAIDs, may increase your risk of heart attack, stroke, or blood clots. People with a history of heart problems should avoid taking this drug unless approved by their healthcare provider.

Never take more Relafen than directed by your practitioner. Taking more than prescribed may increase your risk of experiencing severe side effects.

Relafen and Pregnancy

People trying to become pregnant should avoid taking Relafen because the drug may affect ovulation.


Some drugs may interact with Relafen, including:

  • Blood thinners
  • Other NSAIDs
  • Oral steroids
  • SSRIs (selective serotonin reuptake inhibitors)
  • SNRIs (serotonin and norepinephrine reuptake inhibitors)

Always tell your healthcare provider about any supplements and medications you’re taking as well. 

A Word From Verywell

Whenever you’re starting a new drug, pay attention to how your body responds. If you experience any out-of-the-ordinary side effects, talk to your practitioner. Some serious side effects may require you to stop taking the medication. 

Side effects that aren’t life-threatening can still be bothersome. Your healthcare provider may be able to prescribe another medication that works for you and causes fewer adverse symptoms. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Nabumetone.

  2. Arthritis Foundation. Nabumetone.

  3. Memorial Sloan Kettering Cancer Center. Nabumetone.

  4. National Institute of Kidney Diseases. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury.

  5. DailyMed. Relafen-nabumetone tablet.