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NSAID (Non-selective COX Inhibitor) Pregnancy: Avoid in third trimester (premature closure of ductus arteriosus, inhibition of labour). Short courses in first/second trimester with caution — preferably avoid. Paracetamol preferred.

Naproxen

Brand names: Naprosyn, Anaprox, Feminax Ultra

Adult dose

Dose: Pain/inflammation: 250–500mg BD; maximum 1g daily. Acute gout: 750mg initially, then 500mg every 8h until attack resolves (max 1250mg on day 1, then 1g daily). Dysmenorrhoea: 500mg initially, then 250mg every 6–8h (max 1250mg on day 1 then 1g daily).
Route: Oral
Frequency: Twice daily (standard dosing)
Max: 1250mg on first day (acute gout); 1g daily thereafter
Naproxen has a more favourable cardiovascular profile among NSAIDs — considered the lowest CV risk NSAID at standard doses (NICE recommendation). Longer half-life than ibuprofen — BD dosing preferred over TDS. Always prescribe with PPI (omeprazole 20mg OD) if >4 weeks use, age >45, or GI risk factors.

Paediatric dose

Dose: 5 mg/kg
Route: Oral
Frequency: Twice daily
Max: 1g daily
BNFc: Juvenile idiopathic arthritis (2–17 years): 5mg/kg BD (max 500mg BD). Seek specialist paediatric rheumatology opinion.

Dose adjustments

Renal

eGFR <30: avoid — NSAIDs worsen renal function; risk of AKI, fluid retention, and hyperkalaemia.

Hepatic

Severe hepatic impairment: avoid — reduced clearance, increased GI bleeding risk.

Paediatric weight-based calculator

BNFc: Juvenile idiopathic arthritis (2–17 years): 5mg/kg BD (max 500mg BD). Seek specialist paediatric rheumatology opinion.

Clinical pearls

  • NICE CG177: naproxen preferred NSAID for patients with cardiovascular risk (lowest CV risk among NSAIDs at standard doses). Avoid diclofenac and etoricoxib in CV disease
  • GI protection: co-prescribe omeprazole 20mg OD for all patients on NSAIDs aged >65, or with history of peptic ulcer, or on concurrent steroids/anticoagulants
  • Triple whammy: NSAID + ACE inhibitor/ARB + diuretic = high risk of AKI — avoid this combination, particularly in elderly or volume-depleted patients
  • Sick day rules: advise patients to stop naproxen when acutely unwell, fasting, or dehydrated — AKI risk

Contraindications

  • Active peptic ulcer or GI bleeding
  • eGFR <30
  • Severe heart failure
  • Third trimester of pregnancy
  • CABG peri-operative
  • Hypersensitivity to NSAIDs or aspirin (cross-reaction)

Side effects

  • GI upset, peptic ulceration, GI bleeding
  • AKI (particularly in volume-depleted patients)
  • Fluid retention, oedema
  • Hypertension
  • Cardiovascular events (MI, stroke — at high doses/long-term)
  • Bronchospasm (aspirin-sensitive asthma)
  • Headache
  • Rash

Interactions

  • ACE inhibitors/ARBs — triple whammy with diuretics (AKI risk); avoid combination unless essential
  • Warfarin — increased bleeding risk; monitor INR
  • Lithium — NSAIDs increase lithium levels; monitor levels
  • Methotrexate — NSAIDs reduce methotrexate excretion; toxicity risk

Monitoring

  • eGFR and electrolytes (before starting and periodically)
  • Blood pressure
  • GI symptoms (gastroprotection adequacy)
  • Oedema

Reference: BNFc; BNF 90; NICE CG177 (Osteoarthritis); NICE NG146 (Rheumatoid Arthritis). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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