Augmentin Dosing for a 15-Year-Old with Sinusitis (161 lbs)
For a 15-year-old weighing 161 pounds (73 kg) with sinusitis, the recommended dose is Augmentin 875 mg/125 mg twice daily for 10-14 days. 1, 2
Rationale for Adult Dosing in This Patient
At 15 years old and 161 pounds, this patient should receive adult dosing rather than pediatric weight-based dosing, as they exceed the typical weight threshold where adult fixed-dose regimens are appropriate 3, 1
The standard adult dose of 875 mg amoxicillin/125 mg clavulanate twice daily has been validated in multiple clinical trials for acute bacterial sinusitis and provides adequate tissue concentrations to cover common pathogens including S. pneumoniae and H. influenzae 1, 2, 4
Treatment Duration and Monitoring
Continue treatment for 10-14 days, which represents the standard duration recommended by the Infectious Diseases Society of America 1, 2
Assess clinical response at 72 hours (3 days) of treatment 3, 1
When High-Dose Regimen Would Be Indicated
High-dose Augmentin (90 mg/kg amoxicillin component, not exceeding 2 g every 12 hours) should be reserved for specific scenarios including recent antibiotic use within 4-6 weeks, suspected resistant organisms, or moderate-to-severe disease 3, 1, 2
For this patient weighing 73 kg, high-dose would theoretically be approximately 6,570 mg amoxicillin daily, but the practical maximum is 2,000 mg amoxicillin twice daily (which would require two 875 mg tablets plus additional amoxicillin) 3
However, a recent 2021 randomized trial found no benefit of high-dose over standard-dose amoxicillin-clavulanate in adults with acute sinusitis, with similar efficacy (44.3% vs 36.4% improvement at day 3, p=0.35) and similar rates of severe diarrhea (7.0% vs 7.7%) 5
Important Clinical Considerations
Antibiotics should only be used if bacterial sinusitis is confirmed, not for viral upper respiratory infections, as inappropriate use contributes to antibiotic resistance 2, 6
Gastrointestinal side effects are common, with diarrhea occurring in approximately 40% of patients taking amoxicillin-clavulanate 5
- Taking the medication with food may reduce GI upset 4
For penicillin-allergic patients, alternatives include doxycycline, trimethoprim-sulfamethoxazole, or respiratory fluoroquinolones, though these have higher bacteriologic failure rates (20-25%) 3, 6
Common Pitfalls to Avoid
Do not use pediatric weight-based dosing formulations (such as the 90 mg/6.4 mg per kg suspension) in adolescents who can take adult tablets, as this is unnecessary and more expensive 3, 1
Ensure the patient completes the full 10-14 day course even if symptoms improve earlier, as incomplete treatment can lead to relapse 2, 6
Do not automatically escalate to high-dose therapy without evidence of treatment failure or risk factors for resistance, as standard dosing is equally effective with potentially fewer side effects 5