Amoxicillin Dosing for Acute Sinusitis
For adults with acute bacterial sinusitis, the recommended dosing of amoxicillin is 500 mg three times daily or 875 mg twice daily for 5-7 days. 1, 2, 3
Adult Dosing Options
- Standard dosing: Amoxicillin 500 mg three times daily (every 8 hours) for 5-7 days 1, 2
- Alternative dosing: Amoxicillin 875 mg twice daily (every 12 hours) for 5-7 days 1, 3
- For more resistant infections, amoxicillin-clavulanate may be preferred with dosing of 500 mg/125 mg three times daily or 875 mg/125 mg twice daily 2
Treatment Duration
- The recommended duration for acute bacterial sinusitis treatment is 5-7 days for adults 1, 2
- Treatment should be continued until the patient has been symptom-free for approximately 7 days, with a total course typically lasting 10-14 days in more severe cases 1, 3
Treatment Response Assessment
- Patient response should be evaluated after 3-5 days of amoxicillin therapy 2
- If symptoms worsen or fail to improve after 3-5 days, consider switching to high-dose amoxicillin-clavulanate or another antibiotic 2, 3
Efficacy Considerations
- Clinical studies show comparable efficacy between standard-dose and high-dose amoxicillin formulations for most uncomplicated cases of acute bacterial sinusitis 4, 5
- A randomized clinical trial found no significant benefit of high-dose amoxicillin plus clavulanate compared to standard-dose for adults with acute sinusitis (44.3% vs 36.4% improvement at day 3) 4
- However, one study found that immediate-release high-dose amoxicillin showed better improvement rates compared to standard-dose (52.4% vs 34.4%) 5
Common Pitfalls to Avoid
- Using antibiotics for viral sinusitis is inappropriate and contributes to antibiotic resistance 1, 3
- Stopping antibiotics prematurely when symptoms improve can lead to incomplete eradication and potential relapse 1
- Failing to reassess treatment efficacy at 3-5 days may delay necessary changes in antibiotic therapy 2, 3
- Not considering adjunctive therapies such as intranasal saline irrigation and intranasal corticosteroids, which can improve outcomes 2