What is the recommended dose of naproxen (Nonsteroidal Anti-Inflammatory Drug (NSAID)) per weight?

Naproxen Weight-Based Dosing

Pediatric Dosing (Children and Adolescents)

For juvenile arthritis, the recommended dose is approximately 10 mg/kg/day divided into two doses (5 mg/kg twice daily). 1

Key Pediatric Considerations:

• Naproxen oral suspension is the preferred formulation for pediatric patients rather than tablets, as tablets are not well-suited to weight-based dosing adjustments 1
• Pharmacokinetic studies demonstrate that peak plasma levels and half-life in children are similar to adults, supporting a twice-daily dosing regimen 2
• The absorption, distribution, and elimination of naproxen in children (mean age 10.8 years) does not differ significantly from adults 2

Adult Dosing (Not Weight-Based)

Adults receive fixed dosing rather than weight-based dosing:

Standard Adult Dosing by Indication:

• Rheumatoid arthritis, osteoarthritis, ankylosing spondylitis: 250-500 mg twice daily 1
• Acute pain, dysmenorrhea, tendonitis/bursitis: Initial dose 500 mg, then 500 mg every 12 hours or 250 mg every 6-8 hours (maximum 1,250 mg first day, then 1,000 mg/day thereafter) 1
• Acute gout: 750 mg initially, then 250 mg every 8 hours until attack subsides 1
• Maximum daily dose for routine long-term use: 1,000 mg/day 3
• Short-term higher dosing: Up to 1,500 mg/day may be used for limited periods (up to 6 months) when higher anti-inflammatory activity is required 1

Special Adult Populations Requiring Dose Adjustment:

Elderly patients:

• Use the lowest effective dose as the unbound plasma fraction of naproxen increases with age, even though total plasma concentration remains unchanged 1
• Dose adjustment may be required when using higher doses 4

Renal impairment:

• Naproxen is NOT recommended for patients with moderate to severe renal impairment (creatinine clearance <30 mL/min) 1, 4
• Use caution and consider lower doses in mild renal impairment 1

Hepatic impairment:

• Consider lower starting doses and titrate upward based on response 1

Critical Safety Monitoring

All patients on naproxen require monitoring every 3 months:

• Blood pressure, BUN, creatinine, liver function tests, CBC, and fecal occult blood 3, 4

Discontinuation criteria:

• BUN or creatinine doubles 3
• Liver function tests increase to 3× upper limit of normal 3
• GI bleeding occurs 3, 4
• Hypertension develops or worsens 3

Important Clinical Caveats

• Formulation differences matter: Naproxen tablets, suspension, delayed-release tablets, and naproxen sodium tablets have different pharmacokinetic profiles affecting onset of action, though all circulate as naproxen 1
• Linear pharmacokinetics up to 500 mg: Doses above 500 mg increase the unbound drug fraction, leading to increased renal clearance 5, 6
• Avoid in cardiovascular disease: Use with extreme caution as NSAIDs cause 3.5 excess cardiac ischemic events per 1,000 persons compared to placebo 4
• GI bleeding risk is age-dependent: 1 in 2,100 for adults <45 years versus 1 in 110 for adults >75 years 4
• Drug interactions: Combining with anticoagulants increases GI bleeding risk 3-6 fold and can increase INR by up to 15% 4