What is the next treatment option for acute sinusitis that fails to respond to amoxicillin (amoxicillin)?

Treatment Options for Acute Sinusitis After Amoxicillin Failure

For acute sinusitis that fails to respond to amoxicillin, the next treatment option should be amoxicillin-clavulanate or a respiratory fluoroquinolone such as levofloxacin or moxifloxacin. 1

Definition of Treatment Failure

Treatment failure in acute bacterial sinusitis should be assessed at the appropriate time point:

• Defined as persistent or worsening symptoms after 7 days of initial antibiotic therapy 2
• Early assessment (3-5 days) may lead to premature classification as treatment failure, as improvement rates at this stage are only 30-40% 2

Next-Line Treatment Options

First Choice: Amoxicillin-Clavulanate

• Dosage: 875/125 mg twice daily for 5-7 days 1
• For high-risk patients: Consider high-dose amoxicillin-clavulanate (2000 mg amoxicillin component twice daily) 1
• High-risk factors include:
  • Recent antibiotic use
  • Age >65 years
  • Healthcare exposure
  • Immunocompromised state
  • High local prevalence of resistant bacteria 1

Alternative Options (for penicillin allergy or continued treatment failure):

1. Respiratory Fluoroquinolones:

   • Levofloxacin 500 mg daily for 10-14 days 1, 3
   • Moxifloxacin 400 mg daily for 10 days 1, 4
   • Particularly effective against drug-resistant bacteria including penicillin-resistant S. pneumoniae 3

2. Cephalosporins (for non-severe penicillin allergy):

   • Cefuroxime: 500 mg twice daily for 5-7 days
   • Cefpodoxime: 200-400 mg twice daily for 5-7 days
   • Cefdinir: 14 mg/kg/day divided once or twice daily for 5-7 days 1

3. For severe penicillin allergy:

   • Doxycycline 1
   • Clarithromycin or azithromycin may be considered, though resistance rates are increasing 5

Decision Algorithm

1. Confirm true treatment failure: Ensure symptoms have persisted or worsened after 7 days of appropriate amoxicillin therapy 2

2. Consider possible causes of failure:

   • Non-bacterial cause
   • Infection with drug-resistant bacteria
   • Inadequate dosing of initial therapy 2

3. Select next therapy based on risk factors:

   • Low risk for resistant pathogens: Amoxicillin-clavulanate standard dose
   • High risk for resistant pathogens: High-dose amoxicillin-clavulanate or respiratory fluoroquinolone
   • Penicillin allergy: Respiratory fluoroquinolone or appropriate cephalosporin (if non-anaphylactic)

Supportive Measures

In addition to antibiotic therapy, consider:

• Intranasal saline irrigation to help clear mucus and reduce congestion
• Intranasal corticosteroids as adjunctive therapy
• Analgesics (acetaminophen or NSAIDs) for pain relief
• Decongestants for symptomatic relief 1

Important Considerations

• Monitor for complications of sinusitis, including orbital or intracranial spread of infection 2
• If no improvement after 72 hours of second-line therapy, consider imaging and specialist referral 1
• Fluoroquinolones carry risks including tendinitis, peripheral neuropathy, and CNS effects, so use them only when necessary 3, 4
• Shorter courses of antibiotic therapy (5-7 days) are generally sufficient for uncomplicated acute sinusitis 1, 6

Remember that when changing antibiotics, consider the initial agent's limitations in coverage to ensure the new antibiotic addresses potential resistant organisms 2.