Naproxen Dosing for a 14-Year-Old Weighing 96 kg
For this 14-year-old adolescent weighing 96 kg (211 lb), the appropriate naproxen dose is 500 mg twice daily, using adult dosing rather than pediatric weight-based calculations. 1
Rationale for Adult Dosing
Children weighing more than 40 kg should receive adult dosing rather than pediatric weight-based calculations. 2 This patient at 96 kg far exceeds this threshold.
The FDA-approved dosing for rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis is 250 mg, 375 mg, or 500 mg twice daily. 1 Starting at 500 mg twice daily is appropriate for this adolescent's size.
For acute pain conditions (such as acute tendonitis, bursitis, or primary dysmenorrhea), the recommended starting dose is 500 mg followed by 500 mg every 12 hours or 250 mg every 6 to 8 hours, with an initial total daily dose not exceeding 1250 mg and subsequent daily doses not exceeding 1000 mg. 1
Pediatric Weight-Based Context (Not Applicable Here)
The standard pediatric dose for juvenile idiopathic arthritis is approximately 10 mg/kg/day given in 2 divided doses (5 mg/kg twice daily). 1 However, this would yield 480 mg twice daily for this patient, and naproxen tablets are not well suited to precise pediatric weight-based dosing. 1
Clinical trials in adolescents aged 12-16 years with juvenile idiopathic arthritis used fixed doses based on baseline weight rather than precise weight-based calculations, demonstrating good tolerability and efficacy. 3
Practical Dosing Recommendations
Start with 500 mg twice daily (morning and evening doses 12 hours apart). 1
The morning and evening doses do not have to be equal in size, and administration more frequently than twice daily is generally not necessary. 1
During long-term administration, the dose may be adjusted up or down depending on clinical response, with a lower daily dose often sufficing for maintenance therapy. 1
In patients who tolerate lower doses well, the dose may be increased to 1500 mg/day for limited periods of up to 6 months when higher anti-inflammatory activity is required, though this should be reserved for cases where increased clinical benefit clearly offsets potential increased risk. 1
Safety Considerations
Naproxen has a well-established safety profile comparable to placebo and other common analgesics in short-term use, with most adverse events being mild to moderate and primarily gastrointestinal (most commonly dyspepsia). 4
In adolescents aged 12-16 years, naproxen was well tolerated with 80.4% experiencing at least one treatment-emergent adverse event, but with the exception of two events in one patient, all were mild or moderate. 3 Only 23.9% had events considered related to study drug. 3
The most serious adverse event reported in adolescent trials was one case of acute hepatitis leading to discontinuation. 3
Formulation Considerations
Different formulations (tablets, suspension, delayed-release tablets, naproxen sodium tablets) are not necessarily bioequivalent and have pharmacokinetic differences that may affect onset of action. 1
For acute painful conditions requiring prompt pain relief, naproxen sodium is recommended because it is more rapidly absorbed than naproxen base. 1
Onset of pain relief can begin within 1 hour in patients taking naproxen. 1
Common Pitfalls to Avoid
Do not use pediatric weight-based dosing (10 mg/kg/day) for adolescents weighing more than 40 kg, as this leads to unnecessarily complex dosing and is not well suited to available tablet strengths. 1
Do not exceed 1000 mg/day for chronic conditions without clear clinical justification, and limit higher doses (up to 1500 mg/day) to 6 months maximum. 1
Monitor for gastrointestinal symptoms as these are the most common adverse events across all age groups. 3, 4