What are the indications for antibiotics in acute sinusitis (infection of the paranasal sinuses)?

From the Guidelines

Antibiotics are indicated in sinusitis when symptoms are severe, persistent beyond 10 days, or worsening after initial improvement ("double worsening"). This recommendation is based on the most recent and highest quality study available, which suggests that clinicians should reserve antibiotic treatment for acute rhinosinusitis for patients with persistent symptoms for more than 10 days, onset of severe symptoms or signs of high fever (>39 °C) and purulent nasal discharge or facial pain lasting for at least 3 consecutive days, or onset of worsening symptoms following a typical viral illness that lasted 5 days that was initially improving (double sickening) 1.

Key Considerations

• Most patients with acute rhinosinusitis have more adverse effects than benefits from antibiotics, with a number needed to treat of 18 for 1 patient to be cured rapidly, but the number needed to harm from adverse effects from antibiotics was 8 1.
• First-line treatment is amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days, or amoxicillin 500 mg three times daily for patients with mild disease.
• For penicillin-allergic patients, doxycycline 100 mg twice daily or a respiratory fluoroquinolone like levofloxacin 750 mg daily can be used.
• Supportive measures like saline irrigation, intranasal corticosteroids, and analgesics should accompany antibiotic therapy to provide symptom relief.

Patient Selection

• Patients with immunocompromise, severe symptoms, or complications like orbital or intracranial involvement require immediate antibiotic therapy.
• Patients who are seriously ill, who deteriorate clinically despite antibiotic therapy, or who have recurrent episodes should be referred to a specialist (for example, an otolaryngologist, infectious disease specialist, or allergist) 1.

Evidence Summary

The evidence suggests that antibiotics should be reserved for bacterial sinusitis, as most cases (90%) are viral and resolve without antibiotics within 7-10 days 1. Signs suggesting bacterial infection include purulent nasal discharge, facial pain, tooth pain, fever, and symptoms lasting beyond 10 days. Antibiotics work by targeting bacterial cell walls or protein synthesis, helping clear the infection when the body's natural defenses are insufficient.

From the FDA Drug Label

1.4 Acute Bacterial Sinusitis: 5 Day and 10 to 14 Day Treatment Regimens Levofloxacin tablets are indicated for the treatment of acute bacterial sinusitis due to Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis [see Clinical Studies (14.4)]. To evaluate the safety and efficacy of a high dose short course of levofloxacin, 780 outpatient adults with clinically and radiologically determined acute bacterial sinusitis were evaluated in a double-blind, randomized, prospective, multicenter study comparing levofloxacin 750 mg by mouth once daily for five days to levofloxacin 500 mg by mouth once daily for 10 days Clinical success rates (defined as complete or partial resolution of the pre-treatment signs and symptoms of ABS to such an extent that no further antibiotic treatment was deemed necessary) in the microbiologically evaluable population were 91.4% (139/152) in the levofloxacin 750 mg group and 88.6% (132/149) in the levofloxacin 500 mg group at the test-of-cure (TOC) visit

• Indication of antibiotics in sinusitis: Levofloxacin is indicated for the treatment of acute bacterial sinusitis due to Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis.
• Treatment regimens: The recommended treatment regimens for acute bacterial sinusitis are 750 mg by mouth x 5 days or 500 mg by mouth once daily x 10 to 14 days.
• Clinical success rates: The clinical success rates for levofloxacin in the treatment of acute bacterial sinusitis were 91.4% in the 750 mg group and 88.6% in the 500 mg group at the test-of-cure visit 2.

From the Research

Indications for Antibiotics in Sinusitis

• Antibiotics should be considered for patients with severe symptoms of sinusitis or in patients with moderate symptoms of more than 7 days duration 3
• The decision to prescribe antibiotics should be based on the severity and duration of symptoms, as well as the presence of certain clinical features such as purulent rhinorrhoea, purulent secretions in the nasal cavity, and tooth pain 3
• Patients with symptoms for less than 7 days are not as likely to have bacterial infection and may not require antibiotics 3

Recommended Antibiotics for Sinusitis

• Amoxicillin is a commonly recommended antibiotic for the treatment of acute bacterial sinusitis, and is as effective as amoxicillin-clavulanate for patients without a beta-lactam allergy 4
• For patients with a beta-lactam allergy, doxycycline or a respiratory fluoroquinolone may be appropriate alternatives 4
• High-dose amoxicillin/clavulanate may be more effective than standard-dose for some patients, but is also associated with a higher risk of side effects such as severe diarrhea 5

Treatment Duration and Efficacy

• The recommended treatment duration for acute bacterial sinusitis is typically 10-14 days 6, 7
• Short-course (5-day) gatifloxacin therapy has been shown to be associated with comparable clinical cure rates and tolerability to standard 10-day therapy with gatifloxacin or amoxicillin/clavulanate 6
• The efficacy of antibiotics for sinusitis may vary depending on the specific antibiotic and patient population, and further study is needed to confirm the findings of individual studies 5