Nabumetone (Relafen): Uses, Warnings, and Key Facts

What is nabumetone?

Nabumetone is an active ingredient used for the treatment of rheumatoid arthritis, osteoarthritis, and acute periarticular pain.

In the United States, the brand names listed in the source content are Relafen and Relafen DS.

How nabumetone works

Nabumetone works by inhibiting prostaglandin synthesis through cyclooxygenase-2 (COX-2) inhibition. The source content also notes effects on inflammatory activity in synovial tissue and fluid, free radical activity at the site of inflammation, arachidonic acid metabolites, and leukocyte activity.

Uses and therapeutic indications

The source content lists nabumetone for the following uses:

• Acute and chronic osteoarthritis
• Chronic and acute rheumatoid arthritis
• Acute periarticular ailments

Dosage and administration

The source content lists oral nabumetone in 500 mg and 750 mg strengths.

It also states that adult dosing may be 1 g/day as a single dose, with possible increase to 1,500 mg or 2 g/day in a single or divided dose.

Nabumetone is taken by mouth and may be taken with or without food.

Important: Always verify the exact dose, timing, and duration on the official product information or with a healthcare professional.

Contraindications

The source content lists nabumetone as contraindicated in the following situations:

• Hypersensitivity to nabumetone
• History of gastrointestinal bleeding or perforation related to previous NSAID treatment
• Active or recurrent peptic ulcer or gastrointestinal bleeding
• Severe heart failure
• Third trimester of pregnancy

Warnings and precautions

The source content highlights several situations that require caution or monitoring:

• Severe kidney and/or liver failure
• History of asthma triggered by aspirin or other NSAIDs, hives, or other allergic reactions
• History of ulcer, hemorrhage, or gastrointestinal perforation
• High blood pressure and/or heart failure
• Use with oral anticoagulants
• Use with aspirin-type antiplatelet medicines
• Use with oral corticosteroids or selective serotonin reuptake inhibitor (SSRI) antidepressants
• Patients with hypertension, congestive heart failure, coronary artery disease, peripheral artery disease, cerebrovascular disease, or cardiovascular risk factors such as smoking, diabetes, hyperlipidemia, or hypertension
• Possible worsening of Crohn’s disease or ulcerative colitis
• Need for laboratory, liver, and kidney monitoring
• Avoid use with other NSAIDs, including selective COX-2 inhibitors
• Not recommended for children
• May affect female fertility
• Risk of severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis

If signs of hypersensitivity or severe skin reaction appear, the source content advises stopping treatment and seeking medical attention promptly.

Liver and kidney considerations

The source content advises caution in severe liver failure and severe renal failure.

If liver or kidney disease is present, the official leaflet and a clinician’s advice are especially important before use.

Drug interactions

The source content lists these interaction concerns:

• Higher risk of gastrointestinal bleeding or ulcer with oral anticoagulants, aspirin-type antiplatelet medicines, oral corticosteroids, and SSRI antidepressants
• Avoid use with other NSAIDs, including selective COX-2 inhibitors
• Possible reduction in the effect of antihypertensive medicines, including diuretics
• Possible increase in toxicity of lithium and methotrexate

Pregnancy and breastfeeding

The source content states that nabumetone is not recommended in the first and second trimesters of pregnancy unless absolutely necessary and is contraindicated in the third trimester.

For breastfeeding, the source notes limited human experience and says use should be restricted to situations where the potential benefit to the mother justifies the potential risk to the infant.

Effects on driving and machinery

The source content warns that nabumetone may cause vertigo or other central nervous system effects. If this happens, driving or using machinery should be avoided.

Adverse reactions and side effects

The source content lists the following adverse reactions:

• Nausea
• Diarrhoea
• Vomiting
• Epigastric pain
• Transit disorders
• Ulcers
• Perforations
• Haemorrhagic colitis
• Digestive ulcerations with or without haemorrhage
• Occult or visible haemorrhage
• Anorexia

Frequently asked questions

Sources and references

The source content states that the information was prepared using clinical and molecular information from medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the FDA Substance Registration System and the United States Pharmacopeia (USP).

• FDA Medication Guides
• UNII: LW0TIW155Z
• ChemIDplus
• DrugPortal
• PubChem CID: 4409
• NCI Thesaurus: C47627