What is the appropriate dosing of Amoxicillin (amoxicillin) for acute sinusitis?

From the Guidelines

For acute sinusitis, the recommended dose of amoxicillin 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, as per the most recent guidelines 1.

Key Considerations

• The dosage may vary depending on the severity of the infection and the presence of risk factors such as recent antibiotic use, treatment failure, or immunocompromised status.
• In areas with high prevalence of resistant bacteria, amoxicillin-clavulanate is preferred at 875/125 mg twice daily for adults or 90 mg/kg/day of amoxicillin component for children.
• Treatment should be continued for at least 5 days, and patients should continue therapy for 48-72 hours after symptoms improve.

Mechanism of Action

• Amoxicillin works by inhibiting bacterial cell wall synthesis.
• The addition of clavulanate helps overcome resistance by inhibiting beta-lactamase enzymes that would otherwise break down amoxicillin.

Side Effects

• Common side effects include diarrhea, nausea, and rash.

Importance of Completing the Full Course

• Patients should complete the full course of antibiotics even if symptoms improve before finishing the prescription to prevent recurrence and antibiotic resistance, as recommended by the American Academy of Pediatrics 1.

Recent Guidelines

• The most recent guidelines from the American Academy of Pediatrics recommend amoxicillin as the first-line treatment for acute sinusitis in children, with the option to use amoxicillin-clavulanate in cases where resistance is suspected 1.
• The Infectious Diseases Society of America also recommends amoxicillin-clavulanate as the initial empirical therapy for acute bacterial sinusitis in children 1.

From the Research

Amoxicillin Dosing for Acute Sinusitis

• The optimal duration of amoxicillin therapy for acute sinusitis is not well established, with studies suggesting varying durations of treatment 2, 3.
• A study comparing 3- and 6-day regimens of azithromycin with a 10-day amoxicillin-clavulanate regimen found that the shorter regimens were equivalent in efficacy and better tolerated than the longer regimen 4.
• Another study found that a 5-day course of amoxicillin-clavulanate was not equivalent to a 10-day course in terms of therapeutic success, but the 5-day course may be suitable for patients without specific risk factors 3.
• A randomized controlled trial found that amoxicillin (500 mg three times a day for 7 days) was not effective in treating acute maxillary sinusitis, either alone or in combination with topical budesonide 5.
• A cohort study comparing amoxicillin-clavulanate to amoxicillin for pediatric acute sinusitis found no difference in treatment failure, but a higher risk of gastrointestinal symptoms and yeast infections with amoxicillin-clavulanate 6.

Key Findings

• The duration of amoxicillin therapy for acute sinusitis may be shorter than traditionally recommended, with some studies suggesting 5-7 days as sufficient 2, 3.
• Amoxicillin-clavulanate may be associated with a higher risk of adverse events, such as gastrointestinal symptoms and yeast infections, compared to amoxicillin alone 6.
• The efficacy of amoxicillin in treating acute sinusitis may depend on the specific patient population and the presence of risk factors 3.