What is the recommended dose of amoxicillin (amoxicillin) for an 11-year-old girl with a sinus infection?

Amoxicillin Dosing for Sinus Infection in an 11-Year-Old Girl

For an 11-year-old girl with sinus infection, the recommended dose of amoxicillin is 45 mg/kg/day divided into two doses for 10-14 days, with high-dose amoxicillin at 80-90 mg/kg/day recommended if there are risk factors for resistant organisms. 1

Initial Dosing Recommendations

• Standard dose amoxicillin (45 mg/kg/day divided in two doses) is appropriate as first-line therapy for uncomplicated acute bacterial sinusitis in children who have not recently received antibiotics 1, 2
• High-dose amoxicillin (80-90 mg/kg/day divided in two doses) should be used if there are risk factors for resistant organisms, such as:
  • Recent antibiotic exposure (within previous 30 days) 1
  • Attendance at daycare 2
  • Lack of response to initial standard-dose therapy 2

Duration of Treatment

• Treatment should continue for 10-14 days 1, 3
• Some guidelines recommend continuing treatment until 7 days after the patient becomes symptom-free 3
• Stopping antibiotics prematurely when symptoms improve can lead to incomplete eradication and potential relapse 3

Monitoring and Follow-up

• Clinical improvement should be assessed at 3-5 days after starting treatment 1, 3
• If no improvement is observed after 3-5 days, consider:
  • Switching to high-dose amoxicillin-clavulanate (if not already using) 1, 2
  • Alternative antibiotics such as cefuroxime axetil or cefdinir 3, 2
• For patients showing improvement, continue treatment to complete the full 10-14 day course 3

Alternative Options

• For patients with penicillin allergy, second- or third-generation oral cephalosporins (such as cefdinir or cefpodoxime) may be used 2
• For patients who cannot tolerate oral medication or who are vomiting, a single 50 mg/kg dose of ceftriaxone can be given intravenously or intramuscularly 1
• Clarithromycin has been suggested as an alternative for beta-lactam allergic patients 2

Important Considerations

• The presence of colored nasal discharge does not significantly affect the efficacy of antibiotic treatment 4
• Recent research suggests that testing for specific bacteria may help identify children who would benefit most from antibiotics, as those without nasopharyngeal bacterial pathogens show minimal benefit from antibiotic treatment 4
• Amoxicillin-clavulanate provides better coverage against β-lactamase-producing H. influenzae and M. catarrhalis but has more gastrointestinal side effects than amoxicillin alone 1, 2

Common Pitfalls to Avoid

• Failing to reassess treatment efficacy at 3-5 days may delay necessary changes in antibiotic therapy for non-responders 3
• Using inadequate dosing for patients at risk of resistant organisms 1, 2
• Stopping antibiotics too early when symptoms improve 3