Non-acidic NSAID prodrug Pregnancy: Contraindicated during the third trimester of pregnancy and in nursing mothers. During the first and second trimesters nabumetone should not be given unless clearly necessary, and if used by a woman attempting to conceive or in the first or second trimester the dose should be kept as low and the duration as short as possible. From the 20th week of pregnancy onward nabumetone may cause oligohydramnios resulting from foetal renal dysfunction, and ductus arteriosus constriction has been reported following treatment in the second trimester — antenatal monitoring for both should be considered after exposure for several days from gestational week 20 onward, and nabumetone discontinued if either is found. In the third trimester all prostaglandin synthesis inhibitors may expose the foetus to cardiopulmonary toxicity (premature closure of the ductus arteriosus and pulmonary hypertension) and renal dysfunction, and the mother and neonate to possible prolongation of bleeding time and inhibition of uterine contractions resulting in delayed or prolonged labour. Epidemiological data suggest an increased risk of miscarriage, cardiac malformation and gastroschisis after use of a prostaglandin synthesis inhibitor in early pregnancy, with absolute risk of cardiovascular malformation increased from less than 1% to approximately 1.5%.

Nabumetone

Brand names: Relifex

Nabumetone is a non-steroidal anti-inflammatory drug (NSAID) used for the symptomatic relief of pain and inflammation in osteoarthritis and rheumatoid arthritis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1 g (two 500 mg tablets) as a single dose at bedtime. For severe or persistent symptoms, or during acute exacerbations, an additional 500 mg to 1 g (one or two tablets) may be given as a morning dose.

Route: Oral. Should be taken preferably with or after food.

Frequency: Once daily at bedtime, with an optional additional morning dose for severe or persistent symptoms or acute exacerbations

Max: Elderly: 'The recommended daily dose of two tablets (1 g) should not be exceeded in this age group and in some cases one tablet (500 mg) may give satisfactory relief.' The UK SPC states no explicit numeric maximum daily dose for non-elderly adults beyond the regimen above.

SOURCE: UK SPC (Nabumetone 500 mg film-coated Tablets, https://www.medicines.org.uk/emc/product/11978/smpc), section 4.2. Verbatim: 'The recommended daily dose is two tablets (1 g) taken as a single dose at bedtime. For severe or persistent symptoms, or during acute exacerbations, an additional one or two tablet (500 mg-1 g) may be given as a morning dose.' GENERAL PRINCIPLE (sections 4.2 and 4.4): undesirable effects may be minimised by using the lowest effective dose for the shortest duration necessary to control symptoms. ELDERLY: blood levels may be higher in elderly patients; the recommended daily dose of 1 g should not be exceeded in this age group and in some cases 500 mg may give satisfactory relief. The elderly are at increased risk of the serious consequences of adverse reactions and should be monitored for gastrointestinal bleeding during NSAID therapy. PAEDIATRIC: 'There are no clinical data to recommend use of Nabumetone 500 mg film-coated Tablets in children.' No paediatric dose is stated, so paedDose is null; verify any under-18 use against a children's formulary. CONCOMITANT NSAIDs: use with other NSAIDs, including cyclooxygenase-2 selective inhibitors, should be avoided. HEPATIC MONITORING (section 4.4): a patient with signs or symptoms suggesting liver dysfunction, or an abnormal liver function test while on nabumetone, should be evaluated for a more serious hepatic reaction, and nabumetone discontinued if such a reaction occurs. RESPIRATORY (section 4.4): caution is required in patients with, or with a previous history of, bronchial asthma, since NSAIDs have been reported to precipitate bronchospasm. CARDIOVASCULAR (section 4.4): some NSAIDs, particularly at high doses and in long-term treatment, may be associated with a small increased risk of arterial thrombotic events; there are insufficient data to exclude such a risk for nabumetone. Patients with uncontrolled hypertension, congestive heart failure, established ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease should only be treated with nabumetone after careful consideration. FOR CROSS-REFERENCE ONLY (US labelling, not UK): the US label states a recommended starting dose of 1,000 mg as a single dose with or without food for osteoarthritis and rheumatoid arthritis, that some patients may obtain more symptomatic relief from 1,500 mg to 2,000 mg per day given in either a single or twice-daily dose, that dosages greater than 2,000 mg per day have not been studied, and that patients weighing under 50 kg may be less likely to require dosages beyond 1,000 mg. That regimen is US labelling and requires verification against the UK SPC before use. SPC sections 4.4, 4.6 and 4.8 were truncated at the source-fetch limit.

Dose adjustments

Renal

Renal failure is a contraindication. From UK SPC section 4.4 (not section 4.2): in moderate renal impairment (creatinine clearance 30 to 49 mL/min) there is a 50% increase in unbound plasma 6-MNA and dose reduction may be warranted. In severe renal impairment (creatinine clearance less than 30 mL/min) laboratory tests should be performed at baseline and within some weeks of starting therapy, with further tests as necessary; if the impairment worsens, discontinuation of therapy may be warranted. NSAIDs may cause a dose-dependent reduction in prostaglandin formation and precipitate renal failure, with greatest risk in those with impaired renal function, cardiac impairment, liver dysfunction, those taking diuretics, and the elderly.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to nabumetone or to any of the excipients
Active, or a history of recurrent, peptic ulcer / gastrointestinal haemorrhage, perforation or peptic disease (two or more distinct episodes)
Previous hypersensitivity reactions (e.g. asthma, rhinitis, angioedema or urticaria) in response to ibuprofen, aspirin, acetylsalicylic acid or other non-steroidal anti-inflammatory drugs
Severe heart failure, hepatic failure and renal failure
The last trimester of pregnancy, and nursing mothers
History of gastrointestinal bleeding or perforation related to previous NSAID therapy
Current cerebrovascular or other haemorrhage

Side effects

Gastrointestinal (common): diarrhoea, constipation, dyspepsia, gastritis, nausea, abdominal pain, flatulence; (uncommon) duodenal ulcer, gastrointestinal bleeding, gastric ulcer, melaena, vomiting, stomatitis, dry mouth; (very rare) pancreatitis
Skin (common): rash, pruritus; (uncommon) photosensitivity, urticaria, sweating; (very rare) severe cutaneous adverse reactions including toxic epidermal necrolysis, Stevens-Johnson syndrome, DRESS, erythema multiforme, angioedema, pseudoporphyria and alopecia
Increases in blood pressure (common); tinnitus and ear disorder (common)
Nervous system (uncommon): somnolence, dizziness, headache, paraesthesia, anxiety; (not known) aseptic meningitis, especially in patients with existing autoimmune disorders such as systemic lupus erythematosus or mixed connective tissue disease, vertigo, drowsiness
Renal (uncommon): urinary tract disorder; (very rare) renal failure, nephrotic syndrome; (not known) interstitial nephritis
Haematological (very rare): thrombocytopenia; (not known) neutropenia, agranulocytosis, leucopenia, aplastic anaemia and haemolytic anaemia. Hepatic failure and jaundice are very rare; anaphylaxis and anaphylactoid reaction are very rare

Interactions

NOTE ON SOURCE: UK SPC section 4.5 was NOT fetched in this bundle. The entries below are from the US label (Nabumetone, Drug Interactions section) plus statements in UK SPC section 4.4, and must be checked against UK SPC section 4.5.
Other NSAIDs including cyclooxygenase-2 selective inhibitors — UK SPC section 4.4 states concomitant use should be avoided
ACE inhibitors — NSAIDs may diminish their antihypertensive effect
Aspirin — nabumetone protein binding is reduced when given with aspirin; concomitant administration is not generally recommended because of the potential for increased adverse effects
Diuretics — nabumetone can reduce the natriuretic effect of furosemide and thiazides in some patients; observe closely for signs of renal failure and to assure diuretic efficacy
Lithium — NSAIDs have produced an elevation of plasma lithium levels (mean minimum concentration increased 15%) and a reduction in renal lithium clearance (decreased by approximately 20%)
Diuretics and impaired renal function generally — UK SPC section 4.4 lists patients with impaired renal function, cardiac impairment, liver dysfunction, those taking diuretics and the elderly as being at greatest risk of NSAID-precipitated renal failure

Clinical monograph

How it works

It is a prodrug that is metabolised to an active metabolite which inhibits cyclo-oxygenase, reducing prostaglandin synthesis and thereby decreasing inflammation and pain.

Prescribing in practice

Carries the class NSAID risks of gastrointestinal ulceration and bleeding, cardiovascular thrombotic events and renal impairment; use the lowest effective dose for the shortest duration and avoid in active peptic ulceration.
Use with caution in the elderly, in hypertension, heart failure and in those with established cardiovascular or renal disease.
Avoid concurrent use with other NSAIDs and use caution when combined with anticoagulants, antiplatelets, ACE inhibitors and diuretics.

Monitoring

Monitor blood pressure, renal function and for signs of gastrointestinal bleeding, particularly in older patients and those on long-term therapy.

Counselling the patient

Take with or after food and report any black stools, vomiting of blood or persistent indigestion.
Avoid taking other over-the-counter anti-inflammatory medicines at the same time.

Evidence & guidelines

MHRA guidance and NICE recommend using NSAIDs at the lowest effective dose for the shortest period owing to gastrointestinal and cardiovascular risks.

Reference: NICE NG100; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways