What is the recommended dose of amoxicillin (amoxicillin) for a 5-year-old child weighing 41 pounds with sinusitis?

Amoxicillin Dosing for Sinusitis in a 5-year-old Child Weighing 41 pounds

For a 5-year-old child weighing 41 pounds (approximately 18.6 kg) with sinusitis, the recommended dose of amoxicillin is 40-45 mg/kg/day divided into two doses, which equals approximately 375-400 mg twice daily for 10-14 days. 1, 2

First-Line Treatment Options

• Amoxicillin is the first-line treatment for uncomplicated acute bacterial sinusitis due to its effectiveness, safety, acceptable taste, low cost, and relatively narrow microbiologic spectrum 2
• For standard dosing in uncomplicated cases, amoxicillin should be given at 40-45 mg/kg/day divided into two doses 1, 2
• For this 18.6 kg child, this equals approximately 375-400 mg twice daily 2
• Treatment should continue for 10-14 days or until 7 days after symptoms resolve 1, 2

When to Consider High-Dose Amoxicillin or Amoxicillin-Clavulanate

• In areas with high prevalence of resistant S. pneumoniae, consider high-dose amoxicillin at 80-90 mg/kg/day (approximately 750-850 mg twice daily for this child) 3, 4
• Amoxicillin-clavulanate should be used in scenarios such as:
  • Moderate to severe illness 2
  • Recent antibiotic use (within previous 30 days) 3, 2
  • Treatment failure with standard-dose amoxicillin 1, 4
  • High prevalence of β-lactamase-producing H. influenzae 2
• For high-dose amoxicillin-clavulanate, use 80-90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses 3, 5

Alternative Options for Penicillin Allergy

• For children with penicillin allergy, appropriate alternatives include:
  • Cefdinir, cefuroxime, or cefpodoxime 1, 2
• Avoid trimethoprim/sulfamethoxazole and azithromycin due to resistance patterns 1

Monitoring Response to Treatment

• Evaluate treatment response after 3-5 days 3, 2
• If no improvement is observed after 72 hours, consider:
  • Changing antibiotics if the child is already taking one 1
  • Starting antibiotics if the child was under observation 1
  • Reevaluating the diagnosis 3, 2

Special Considerations

• For children who cannot tolerate oral medication or who are vomiting, a single 50 mg/kg dose of ceftriaxone can be given intravenously or intramuscularly (approximately 930 mg for this child) 1, 3
• After clinical improvement with parenteral therapy, switch to oral antibiotics to complete the course 3
• Children under 2 years are at higher risk for resistant organisms and may benefit from higher doses or broader coverage from the start 3, 4

Common Pitfalls to Avoid

• Treating viral sinusitis with antibiotics is inappropriate and contributes to antibiotic resistance 2
• Not completing the full course of antibiotics can lead to incomplete eradication and potential relapse 2
• Using standard-dose amoxicillin in areas with high resistance patterns may lead to treatment failure 2, 6
• Viral coinfection may reduce the efficacy of standard-dose amoxicillin, supporting the use of higher doses in certain cases 6