Amoxicillin Duration for Acute Bacterial Sinusitis
For adults with acute bacterial sinusitis, amoxicillin should be given for 5-10 days, with most patients treated until symptom-free for 7 days (typically resulting in a 10-14 day total course). 1, 2
Standard Treatment Duration
- The recommended duration is 10-14 days for adults, continuing treatment until the patient has been symptom-free for 7 days. 1, 2
- Recent high-quality evidence demonstrates that shorter courses (5-7 days) have comparable efficacy to traditional 10-day regimens with fewer adverse effects. 1, 3
- The FDA label for amoxicillin states treatment should continue for a minimum of 48-72 hours beyond the time the patient becomes asymptomatic. 4
Dosing Specifications
- For mild disease: amoxicillin 500 mg twice daily (every 12 hours) for 5-10 days. 1, 4
- For moderate-to-severe disease: amoxicillin 875 mg twice daily (every 12 hours) for 5-10 days. 1, 4
- An alternative regimen is 500 mg three times daily (every 8 hours) for 10-14 days. 5, 4
Critical Reassessment Timepoints
- Evaluate patient response at 3-5 days: if no improvement, switch to high-dose amoxicillin-clavulanate (875 mg/125 mg twice daily) or a respiratory fluoroquinolone. 1, 2
- At 7 days: if symptoms persist or worsen, reconfirm the diagnosis and consider complications or alternative diagnoses. 1
- Waiting beyond 7 days to change therapy in non-responders delays effective treatment and may allow complications to develop. 1
When Plain Amoxicillin Is Appropriate
- Plain amoxicillin is appropriate only for patients without recent antibiotic exposure (within past 4-6 weeks), age <65 years, no comorbid conditions, and mild-to-moderate disease. 1
- For patients with recent antibiotic use, age >65 years, moderate-to-severe symptoms, or comorbidities, start with high-dose amoxicillin-clavulanate instead. 1
Essential Adjunctive Therapies
- Add intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily) to reduce mucosal inflammation and improve symptom resolution. 1
- Recommend saline nasal irrigation for symptomatic relief and mucus removal. 1
- Provide analgesics (acetaminophen or ibuprofen) for pain and fever management. 1
Common Pitfalls to Avoid
- Do not prescribe antibiotics for symptoms lasting <10 days unless severe symptoms are present (fever ≥39°C with purulent discharge for ≥3 consecutive days). 1
- Stopping antibiotics prematurely when symptoms improve can lead to incomplete eradication and potential relapse. 2
- Failing to reassess treatment efficacy at 3-5 days may delay necessary changes in antibiotic therapy for non-responders. 1, 2
- Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics—confirm bacterial criteria before prescribing. 1
Evidence for Shorter Courses
- A meta-analysis of 12 randomized controlled trials involving 4,430 patients found no difference in clinical success between short-course (3-7 days) and long-course (6-10 days) treatment. 3
- Sensitivity analysis comparing 5-day versus 10-day regimens showed similar clinical success but fewer adverse events with short-course treatment. 3
- Multiple studies demonstrate that 5-day courses of various antibiotics achieve comparable cure rates (74-80%) to 10-day regimens for uncomplicated acute bacterial sinusitis. 6, 7