From the Guidelines
For adult sinusitis, amoxicillin should be prescribed at a dose of 500 mg three times daily or 875 mg twice daily for 5 to 10 days, as recommended by the clinical practice guideline update for adult sinusitis 1, 2. The choice of amoxicillin with or without clavulanate as first-line therapy is based on randomized controlled trials with heterogeneity and noninferiority design, showing a preponderance of benefit over harm 1. Key considerations for dosing include:
- Duration of treatment: 5 to 10 days for most adults
- Dose frequency: three times daily for 500 mg or twice daily for 875 mg
- Potential for higher dose regimens for patients with risk factors for drug-resistant bacteria, although this is not explicitly stated in the provided guidelines It is essential to complete the full course of antibiotics, even if symptoms improve before finishing the prescription, and to contact a healthcare provider if symptoms worsen or do not improve after 3-5 days.
From the FDA Drug Label
For more severe infections and infections of the respiratory tract, the dose should be one 875 mg/125 mg amoxicillin and clavulanate potassium tablet every 12 hours or one 500 mg/125 mg amoxicillin and clavulanate potassium tablet every 8 hours. The recommended dosing for an adult with sinusitis is:
- 875 mg/125 mg every 12 hours
- 500 mg/125 mg every 8 hours 3
From the Research
Dosing of Amoxicillin for Sinusitis in Adults
- The dosing of amoxicillin for sinusitis in adults is typically initiated with high-dose amoxicillin or amoxicillin-clavulanate 4.
- The optimal duration of therapy is unknown, but some recommend treatment until the patient becomes free of symptoms and then for an additional 7 days 4.
- Alternative treatments include cefuroxime, cefpodoxime, or cefdinir, and in cases of serious drug allergy, clarithromycin or azithromycin may be prescribed 4.
- Studies have compared the efficacy of amoxicillin-clavulanate with other antibiotics, such as azithromycin, and found that azithromycin may be as effective and better tolerated than amoxicillin-clavulanate 5, 6.
- Other studies have compared the efficacy of levofloxacin with amoxicillin-clavulanate and found that levofloxacin may be as effective and better tolerated than amoxicillin-clavulanate 7.
- A novel microsphere formulation of azithromycin given as a single dose has been found to be safe and effective for the treatment of acute bacterial sinusitis in adults 8.
Comparison of Antibiotics
- Azithromycin has been found to be as effective and better tolerated than amoxicillin-clavulanate in the treatment of acute sinusitis in adults 5, 6.
- Levofloxacin has been found to be as effective and better tolerated than amoxicillin-clavulanate in the treatment of acute sinusitis in adults 7.
- A single-dose azithromycin microsphere formulation has been found to be safe and effective for the treatment of acute bacterial sinusitis in adults 8.
Treatment Duration
- The optimal duration of therapy for acute sinusitis is unknown, but some recommend treatment until the patient becomes free of symptoms and then for an additional 7 days 4.
- Studies have used treatment durations ranging from 3 to 10 days, and have found that shorter treatment durations may be as effective as longer treatment durations 5, 6, 7, 8.