What is the recommended treatment for influenza (flu)?

Recommended Treatment for Influenza (Flu)

The recommended treatment for influenza includes antiviral therapy with neuraminidase inhibitors (oseltamivir 75 mg twice daily for 5 days) for patients who have been symptomatic for two days or less, with antibiotics reserved only for cases with suspected bacterial complications. 1, 2

Antiviral Treatment

Indications for Antiviral Therapy

• Antiviral treatment should be considered for patients with acute influenza-like illness, fever (>38°C), and symptoms for two days or less 3, 1
• Treatment should be prioritized for high-risk individuals, including:
  • Children younger than 2 years 3
  • Adults aged 65 years or older 3
  • Pregnant or postpartum women 3
  • Persons with chronic medical conditions 3
  • Immunocompromised patients 3

Recommended Antiviral Medications

• Oseltamivir (oral) is the first-line treatment: 75 mg twice daily for 5 days for adults 2, 1
• Zanamivir (inhaled) is an alternative: 10 mg twice daily for 5 days 4, 5
• Dosage should be reduced by 50% if creatinine clearance is less than 30 ml/min 2, 3

Timing of Antiviral Treatment

• Maximum benefit occurs when treatment is initiated within 48 hours of symptom onset 5, 6
• Treatment should not be delayed while awaiting diagnostic test results 3
• Hospitalized patients who are severely ill may benefit from antiviral treatment even if started more than 48 hours after symptom onset 3, 1

Antibiotic Treatment

Uncomplicated Influenza

• Previously well adults with uncomplicated influenza or acute bronchitis do not routinely require antibiotics 3
• Antipyretics and adequate fluid intake are recommended for symptomatic relief 3, 7

When to Consider Antibiotics

• Antibiotics should be considered for:
  • Patients who develop worsening symptoms (recrudescent fever or increasing dyspnea) 3
  • Patients at high risk of complications with lower respiratory symptoms 3, 1
  • Confirmed or suspected influenza-related pneumonia 3

Antibiotic Selection

• For non-severe cases requiring antibiotics:

  • First-line: Co-amoxiclav or a tetracycline 3, 1
  • Alternative options: Macrolides (clarithromycin or erythromycin) or respiratory fluoroquinolones 3

• For severe influenza-related pneumonia:

  • Immediate treatment with parenteral antibiotics 3
  • Preferred regimen: IV combination of a broad-spectrum beta-lactamase stable antibiotic (co-amoxiclav or cephalosporin) plus a macrolide 3

Duration of Antibiotic Therapy

• Non-severe pneumonia: 7 days of appropriate antibiotics 3
• Severe pneumonia: 10 days of treatment 3
• Extended treatment (14-21 days) for suspected or confirmed Staphylococcus aureus or Gram-negative enteric bacilli pneumonia 3

Special Considerations

Pediatric Patients

• Oseltamivir dosing is weight-based for children 2
• Aspirin should be avoided in children with influenza due to risk of Reye's syndrome 3
• Children under 5 years are at higher risk for complications, with highest risk in those under 2 years 3

Immunocompromised Patients

• May benefit from antiviral treatment even without documented fever 3
• May benefit from treatment started more than 48 hours after symptom onset 3, 1
• May require longer duration of prophylaxis (up to 12 weeks) 2

Common Pitfalls and Caveats

• Delaying antiviral treatment beyond 48 hours significantly reduces effectiveness in uncomplicated cases 5, 6
• Unnecessary antibiotic use in uncomplicated influenza can contribute to antimicrobial resistance 1
• The commercial dry powder formulation of zanamivir should not be administered via nebulization in intubated patients 5
• Staphylococcus aureus is a more common cause of secondary pneumonia during influenza outbreaks than in routine community-acquired pneumonia 1