naproxen
NSAID· Brands: Aleve, Naprosyn, Anaprox, Naprelan, Midol Extended Relief, FlanaxPO
Mechanism of action
Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, COX-1 and COX-2, thereby reducing the synthesis of prostaglandins which mediate inflammation, pain, and fever. It has analgesic, anti-inflammatory, and antipyretic properties.
Pharmacokinetics
Naproxen is well absorbed from the gastrointestinal tract after oral administration. It is extensively bound to plasma albumin (>99%). It has a half-life of approximately 12 to 17 hours, allowing twice-daily dosing. It is metabolized in the liver by CYP1A2 and CYP2C9, and excreted in urine as metabolites and unchanged drug.
Indications & dosing
Rheumatoid arthritis
Use lowest effective dose; monitor GI and renal function.
- adult · PO: 250–500 mg twice daily · Use lowest effective dose; monitor GI and renal function.
Osteoarthritis
Use lowest effective dose; monitor GI and renal function.
- adult · PO: 250–500 mg twice daily · Use lowest effective dose; monitor GI and renal function.
Ankylosing spondylitis
Use lowest effective dose; monitor GI and renal function.
- adult · PO: 250–500 mg twice daily · Use lowest effective dose; monitor GI and renal function.
Acute gout
Initial loading dose of 750 mg, then 250 mg every 8 hours until attack subsides.
- adult · PO: 250 mg every 8 hours · Initial loading dose of 750 mg, then 250 mg every 8 hours until attack subsides.
Dysmenorrhoea
Initial loading dose of 500 mg, then 250 mg every 6-8 hours for up to 3 days.
- adult · PO: 250 mg every 6-8 hours · Initial loading dose of 500 mg, then 250 mg every 6-8 hours for up to 3 days.
Musculoskeletal pain
Initial loading dose of 500 mg, then 250 mg every 6-8 hours as needed.
- adult · PO: 250 mg every 6-8 hours · Initial loading dose of 500 mg, then 250 mg every 6-8 hours as needed.
Contraindications & precautions
- Active peptic ulcer or gastrointestinal bleeding
- Severe heart failure
- Third trimester of pregnancy
- History of NSAID-induced bronchospasm (e.g., asthma)
- Severe renal impairment (eGFR less than 30 ml/min) · Avoid if possible, especially if long-term use is planned
- Concomitant use of other NSAIDs or aspirin (except low-dose aspirin for cardiovascular prophylaxis)
- Use the lowest effective dose for the shortest duration necessary
- Caution in the elderly, as they are at increased risk of gastrointestinal and renal adverse effects
- Monitor blood pressure and renal function, especially during long-term use
- Avoid in patients with cardiovascular disease or significant cardiovascular risk factors
- Caution in patients with fluid retention or oedema, including those with heart failure
- May mask signs of infection, such as fever and inflammation
Adverse effects
- Dyspepsia
- Nausea
- Headache
- Dizziness
- Gastrointestinal bleedingserious
- Peptic ulcerserious
- Renal impairmentserious
- Myocardial infarctionserious
- Bronchospasmserious
- Anaphylaxisserious
Interactions
- lisinoprilmoderatePrescribers should avoid this combination if possible, especially in high-risk patients. If co-administration is necessary, use the lowest effective NSAID dose for the shortest duration, and consider substitution with paracetamol or another non-NSAID analgesic. Monitor serum creatinine, estimated GFR, blood pressure, and serum potassium at baseline, within one week of starting the combination, and thereafter as clinically indicated. Advise patients to maintain adequate hydration and report symptoms such as oedema, reduced urine output, or weakness.
- warfarinmajorAvoid co-prescription where possible. If the combination is essential, use the shortest possible duration of naproxen, monitor INR at least weekly, and consider adding gastroprotection (e.g., a proton pump inhibitor). Counsel the patient to report any symptoms of bleeding. Alternative analgesics such as paracetamol may be preferred.
- lithiummajorAvoid co-prescription if possible; consider alternative analgesics such as paracetamol or aspirin. If combined treatment is necessary, monitor serum lithium concentrations closely at baseline, after 3 to 5 days of starting naproxen, and weekly thereafter. Monitor for signs of lithium toxicity and adjust the lithium dose accordingly. Educate the patient about symptoms of toxicity.
- methotrexatemajorAvoid concurrent use of methotrexate and naproxen, particularly in patients with renal impairment or those receiving high-dose methotrexate. If co-prescription is unavoidable, use the lowest effective doses and monitor closely. Monitor full blood count, renal function, and liver function at baseline and at regular intervals during therapy. Consider measuring serum methotrexate levels where available. Administer methotrexate with folic acid supplementation to reduce some toxicities. Advise patients to report signs of toxicity such as oral ulcers, fever, or easy bruising.
- apixabanmajorAvoid concomitant use unless strongly indicated. If co-prescription is necessary, use the lowest effective dose of naproxen for the shortest duration, consider gastroprotective therapy (e.g., a proton pump inhibitor), and monitor closely for signs of bleeding. Advise the patient to report any unusual bruising, black stools, or blood in vomit. Periodic full blood counts and stool occult blood testing may be considered.
- dabigatranmajorAvoid concomitant use where possible. If anti-inflammatory therapy is needed, prefer an alternative such as paracetamol. When co-administration is unavoidable, use the lowest effective dose of naproxen for the shortest duration, consider gastroprotective therapy (e.g., a proton pump inhibitor), and monitor the patient closely for signs of bleeding, including haemoglobin levels and renal function. Dabigatran dose reduction may be required in renal impairment.
Renal & hepatic adjustment
- eGFR 30–59: Use with caution; consider dose reduction and monitor renal function.
- eGFR 0–29: Avoid use; risk of renal failure. (avoid)
- Hepatic impairment (mild): Use with caution; monitor liver function.
- Hepatic impairment (moderate): Use with caution; monitor liver function; consider dose reduction.
- Hepatic impairment (severe): Avoid use; risk of hepatotoxicity. (avoid)
Monitoring, pregnancy & toxicity
- Serum creatinine and eGFR · Baseline and periodically during therapy
- Blood pressure · Baseline and periodically
- Liver function tests · Baseline and periodically
- GI symptoms (dyspepsia, bleeding) · Throughout therapy
- Signs of cardiovascular events (oedema, hypertension) · Throughout therapy
- Pregnancy: Avoid in pregnancy, especially in the third trimester due to risk of premature closure of the ductus arteriosus and fetal renal impairment. If use is necessary during the first or second trimester, use the lowest effective dose for the shortest duration.
- Toxicity: GI bleeding and ulcers · Activated charcoal if within 1 hour of overdose; supportive care with IV fluids, blood transfusion if needed.
- Toxicity: Renal impairment and acute kidney injury · Monitor renal function; supportive care with fluids; consider haemodialysis in severe cases.
- Toxicity: CNS effects (drowsiness, confusion, seizures) · Supportive care; treat seizures with benzodiazepines as needed.
- Toxicity: Metabolic acidosis · Monitor acid-base balance; supportive care with corrective measures.
Clinical notes
Used for conditions such as rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, musculoskeletal pain, dysmenorrhoea, and acute gout. It is also used for fever and pain. Caution in patients with history of peptic ulcer, renal impairment, or cardiovascular disease. Avoid in third trimester of pregnancy. Consider gastroprotection with PPI in high-risk patients.
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BNF; local formulary; Summary of Product Characteristics (SmPC)