From the Guidelines
The recommended dosage of amoxicillin for treating sinusitis is 45-90 mg/kg/day divided into two doses for children, and 500 mg three times daily or 875 mg twice daily for 5-10 days for adults, with adjustments based on risk factors for resistance and local resistance patterns, as suggested by the American Academy of Pediatrics guideline 1.
Key Considerations for Amoxicillin Dosage
- For children aged 2 years or older with uncomplicated acute bacterial sinusitis, a standard dose of 45 mg/kg per day in 2 divided doses is recommended, unless there are risk factors for resistance, in which case a higher dose of 80-90 mg/kg per day may be used 1.
- Patients presenting with moderate to severe illness, those younger than 2 years, attending child care, or who have recently been treated with an antimicrobial may receive high-dose amoxicillin-clavulanate (80–90 mg/kg per day of the amoxicillin component) 1.
- The optimal duration of antimicrobial therapy for patients with acute bacterial sinusitis has not received systematic study, but recommendations based on clinical observations suggest treatment for 10-28 days or until the patient is symptom-free for 7 days 1.
Important Factors Influencing Dosage
- Risk factors for the presence of organisms likely to be resistant to amoxicillin include attendance at child care, receipt of antimicrobial treatment within the previous 30 days, and age younger than 2 years 1.
- Local patterns of susceptibility should be considered when selecting an antibiotic, as the prevalence of β-lactamase–positive H influenzae can vary dramatically by geographic location 1.
- Patients who are acutely ill and appear toxic may require alternative management strategies, including consultation with an otolaryngologist or inpatient therapy with intravenous cefotaxime or ceftriaxone 1.
From the Research
Amoxicillin Dosage for Sinusitis
The recommended dosage of amoxicillin for treating sinusitis varies depending on the severity of the infection and the patient's medical history.
- The standard dose of amoxicillin for adults with acute bacterial sinusitis is 500 mg three times a day or 875 mg twice a day for 10 to 14 days 2.
- However, some studies suggest that high-dose amoxicillin (875 mg twice a day) may be more effective in eradicating certain pathogens, such as Streptococcus pneumoniae 3.
- A study comparing high-dose amoxicillin plus clavulanate to standard-dose amoxicillin plus clavulanate found no significant difference in clinical cure rates between the two groups 4.
- Other studies have compared the effectiveness of amoxicillin to other antibiotics, such as levofloxacin and azithromycin, in treating acute sinusitis 5, 6.
Dosage Comparison
- A study found that a 3-day course of azithromycin was as effective and well-tolerated as a 10-day course of amoxicillin/clavulanic acid in treating acute sinusitis in adults 6.
- Another study found that once-daily administration of levofloxacin was as effective and better tolerated than amoxicillin-clavulanate administered three times daily for treating acute sinusitis in adult outpatients 5.
- The choice of antibiotic and dosage should be based on the severity of the infection, the patient's medical history, and the susceptibility of the pathogen to the antibiotic 2, 3.