What is the recommended treatment for bacterial sinusitis?

Treatment for Bacterial Sinusitis

First-Line Antibiotic: Amoxicillin-Clavulanate

Amoxicillin-clavulanate is the preferred first-line antibiotic for acute bacterial sinusitis in both adults and children, dosed at 875 mg/125 mg twice daily for adults (5-7 days) and 45-90 mg/kg/day of the amoxicillin component for children (10-14 days). 1

The strong preference for amoxicillin-clavulanate over plain amoxicillin reflects the increasing prevalence of β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis, which now account for a substantial proportion of bacterial sinusitis cases. 1, 2 Plain amoxicillin should not be used as routine first-line therapy given these resistance patterns. 1

Adult Dosing

• Standard dose: 875 mg/125 mg twice daily for 5-7 days 1
• High-dose option: 2 g amoxicillin/125 mg clavulanate twice daily for severe infections or recent antibiotic exposure 1

Pediatric Dosing

• Standard dose (≥2 years, no recent antibiotics): 45 mg/kg/day of amoxicillin component in 2 divided doses 1
• High dose (age <2 years, daycare, recent antibiotics, or high local resistance): 80-90 mg/kg/day of amoxicillin component (maximum 2 g per dose) with 6.4 mg/kg/day clavulanate in 2 divided doses 1

Treatment Duration

• Adults: 5-7 days is sufficient for uncomplicated cases 1
• Children: 10-14 days remains the standard 1

Shorter courses (5-7 days) in adults have comparable efficacy with fewer side effects compared to traditional 10-14 day regimens. 1

Penicillin-Allergic Patients

For patients with documented penicillin allergy, second- or third-generation cephalosporins are safe and effective alternatives, as the risk of cross-reactivity causing serious allergic reactions is negligible. 1

Recommended Cephalosporin Options

• Cefuroxime 1, 3
• Cefpodoxime 1, 3
• Cefdinir 1, 3
• Cefprozil 1

Do not use first-generation cephalosporins (like cephalexin) for sinusitis—they lack adequate coverage against H. influenzae. 1

For Severe Beta-Lactam Allergy

• Respiratory fluoroquinolones (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) should be reserved for patients with true Type I hypersensitivity reactions 1, 4, 5

Second-Line Treatment for Treatment Failure

If no improvement occurs after 3-5 days of initial therapy, switch to a respiratory fluoroquinolone (levofloxacin or moxifloxacin) or escalate to high-dose amoxicillin-clavulanate. 1

Fluoroquinolone Options

• Levofloxacin 500 mg once daily for 10 days 1, 4
• Moxifloxacin 400 mg once daily for 10 days 1, 5

These agents provide 90-92% predicted clinical efficacy and excellent coverage against drug-resistant S. pneumoniae (MDRSP) and β-lactamase-producing organisms. 1, 4

Critical Caveat

Reserve fluoroquinolones for treatment failures, severe disease, or complicated sinusitis—not as routine first-line therapy—to prevent resistance development. 1, 3

Antibiotics to Avoid

• Azithromycin and other macrolides: Do not use due to resistance rates of 20-25% 1, 3
• Trimethoprim-sulfamethoxazole: High resistance rates make this inappropriate 1
• Doxycycline: Limited activity against H. influenzae with 20-25% predicted bacteriologic failure rate 1
• Clindamycin monotherapy: Lacks coverage for H. influenzae and M. catarrhalis 1

Adjunctive Therapies

Intranasal Corticosteroids (Strongly Recommended)

• Use mometasone, fluticasone, or budesonide twice daily 1
• Particularly beneficial in patients with allergic rhinitis 1
• Reduces mucosal inflammation and improves symptom resolution 1

Saline Nasal Irrigation

• Physiologic or hypertonic saline irrigation recommended in adults 1
• Improves mucociliary clearance and reduces nasal congestion 1

Systemic Corticosteroids (Limited Role)

• Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may be reasonable for acute hyperalgic sinusitis (severe pain) or marked mucosal edema 3
• Never use systemic corticosteroids without antibiotics when bacterial sinusitis is suspected 1

Monitoring and Reassessment

Reassess all patients at 72 hours (pediatrics) or 3-5 days (adults) if symptoms worsen or fail to improve. 1

When to Switch Antibiotics

• No improvement after 3-5 days of initial therapy 1
• Worsening symptoms within 48-72 hours 1

When to Refer to Specialist

• Clinical deterioration despite extended antibiotic courses 1
• Recurrent sinusitis (≥3 episodes per year) with clearing between episodes 1
• Suspected complications (orbital or intracranial involvement) 1
• Immunocompromised patients 1

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis—ensure patients meet diagnostic criteria: symptoms >10 days without improvement, severe symptoms (fever >39°C with purulent discharge) for 3-4 days, or worsening after initial improvement 1, 2
• Do not continue ineffective antibiotics beyond 3-5 days—failure to reassess and switch therapy leads to prolonged illness and potential complications 1
• Do not routinely cover for MRSA during initial empiric therapy—current data do not support this practice 1
• Do not use plain amoxicillin as first-line therapy given high prevalence of β-lactamase-producing organisms 1

Special Clinical Situations

Unable to Tolerate Oral Medications

• Ceftriaxone 50 mg/kg IV or IM as a single dose, then transition to oral therapy once tolerated 1
• For adults: ceftriaxone 1-2 g IM or IV once daily for 5 days 1

Severely Ill or Toxic-Appearing Patients

• Initiate inpatient IV therapy with cefotaxime or ceftriaxone 1
• Obtain otolaryngology consultation for possible sinus aspiration 1