What is the recommended dosage and treatment duration of naproxen (naproxen sodium) for muscle strain?

Naproxen Sodium for Muscle Strain

For acute muscle strain, naproxen sodium should be initiated at 500-550 mg immediately, followed by 250-275 mg every 8-12 hours, with treatment duration of 7-14 days depending on symptom resolution. 1, 2, 3

Recommended Dosing Strategy

Initial Dose

• Start with naproxen sodium 550 mg as a loading dose, then 275 mg every 8-12 hours for acute soft tissue injuries like muscle strains 3
• Alternatively, naproxen 500 mg twice daily (every 12 hours) can be used, which is the standard prescription dosing 1, 2
• The sodium salt formulation is preferred for acute painful conditions because it is more rapidly absorbed and provides faster pain relief (onset within 1 hour) 2

Maximum Dosing

• Do not exceed 1,250 mg on the first day 2
• After day one, do not exceed 1,000 mg total daily dose 1, 2
• For over-the-counter naproxen sodium (Aleve), use 440 mg (two 220 mg tablets) twice daily as the equivalent dose 1

Treatment Duration

Treat for 7-14 days based on clinical response, with most patients not requiring the full 14 days 3

• In a study of soft tissue injuries in athletes, 59% of patients stopped naproxen sodium by day 10 due to adequate symptom resolution 3
• Reassess treatment response at 2-4 weeks if symptoms persist beyond the acute phase 1
• Continue treatment until the acute injury has resolved, then discontinue 2

Clinical Efficacy for Muscle Strain

Naproxen sodium demonstrates superior outcomes for soft tissue injuries compared to pure analgesics:

• Reduces swelling more effectively than opioid analgesics (statistically significant improvement on days 2-6) 3
• Patients return to activity approximately 1 day sooner compared to opioid-only treatment 3
• Provides both anti-inflammatory and analgesic effects, addressing the underlying pathophysiology of muscle strain 4, 5

Combination Therapy Consideration

Adding a muscle relaxant like cyclobenzaprine to naproxen provides additional benefit for muscle spasm associated with acute strain 6

• Combination therapy results in less objective muscle spasm, reduced tenderness, and greater range of motion compared to naproxen alone 6
• However, combination therapy increases drowsiness as a side effect 6
• Reserve combination therapy for cases with significant muscle spasm that limits function 6

Important Safety Considerations

Gastrointestinal Risk

• Common GI side effects (dyspepsia, discomfort) occur in 10-20% of patients 1
• Consider gastroprotection with a proton pump inhibitor or H2 blocker in high-risk patients (history of peptic ulcer, age >65, concurrent anticoagulant use) 1
• Discontinue immediately if GI bleeding occurs 1

Cardiovascular Considerations

• Naproxen has lower cardiovascular risk compared to other NSAIDs, making it the preferred NSAID when cardiovascular concerns exist 7, 8
• Use with caution in patients with established cardiovascular disease 7, 1

Renal Precautions

• Avoid in patients with creatinine clearance <30 mL/min 2
• Use caution in elderly patients and consider lower doses 2

Drug Interactions

• Do not combine with other NSAIDs (including low-dose aspirin for cardioprotection increases GI bleeding risk significantly) 7
• NSAIDs significantly increase bleeding risk when combined with anticoagulants 1

Monitoring Requirements

For treatment extending beyond 2 weeks:

• Monitor blood pressure, renal function (BUN, creatinine), and consider fecal occult blood testing 1
• Discontinue if BUN or creatinine doubles 1

When to Switch Therapy

If inadequate response after 7-14 days at maximum tolerated dose, consider switching to a different NSAID or adding alternative modalities (physical therapy, topical treatments) 1