What are the recommended treatments for flu management?

Flu Management: Recommended Treatment Approach

For patients with suspected or confirmed influenza, initiate oseltamivir 75 mg orally twice daily for 5 days as soon as possible, ideally within 48 hours of symptom onset, particularly for hospitalized patients, those with severe illness, high-risk individuals, children under 2 years, adults ≥65 years, and pregnant women. 1, 2

Antiviral Treatment Strategy

Who Should Receive Antivirals

Immediate antiviral treatment is indicated for:

• All hospitalized patients with influenza 1
• Outpatients with severe or progressive illness 1
• High-risk patients including those with chronic cardiac/respiratory disease, immunocompromised status 1, 3
• Children younger than 2 years 1
• Adults ≥65 years of age 1
• Pregnant women 1
• Previously healthy outpatients presenting within 48 hours of symptom onset (consider treatment) 1, 2

Key exceptions to the 48-hour rule:

• Immunocompromised or very elderly patients may benefit from antivirals even without documented fever 4, 5
• Severely ill hospitalized patients may benefit from treatment started beyond 48 hours, though evidence is limited 4, 5

Antiviral Dosing

Standard oseltamivir dosing: 2

• Adults and adolescents ≥13 years: 75 mg orally twice daily for 5 days
• Children 1-12 years (weight-based):
  • ≤15 kg: 30 mg twice daily
  • 15.1-23 kg: 45 mg twice daily
  • 23.1-40 kg: 60 mg twice daily

  • 40 kg: 75 mg twice daily

• Infants 2 weeks to <1 year: 3 mg/kg twice daily 2
• Renal impairment: Reduce dose by 50% if creatinine clearance <30 mL/min 4, 2

Alternative neuraminidase inhibitors: 1

• Inhaled zanamivir (for patients ≥7 years without respiratory disease) 6
• Intravenous peramivir 1

Duration considerations:

• Standard treatment is 5 days 2
• Consider longer duration for immunocompromised patients or those with severe lower respiratory tract disease 1

Expected Benefits

Antiviral treatment provides: 4

• Reduction in illness duration by approximately 24 hours 3, 7
• Possible reduction in hospitalization rates 4
• Decreased subsequent antibiotic use 4
• Important caveat: Current evidence does not demonstrate clear mortality reduction, though it doesn't rule it out 4

Antibiotic Management

Uncomplicated Influenza Without Pneumonia

Antibiotics are NOT routinely required for previously well adults with acute bronchitis complicating influenza in the absence of pneumonia. 4, 5

Consider antibiotics when: 4, 5

• Worsening symptoms develop (recrudescent fever or increasing dyspnea)
• Patients have COPD or other severe pre-existing illnesses
• High-risk patients develop lower respiratory features

Preferred oral antibiotic choices: 4, 5

• Co-amoxiclav (first-line)
• Tetracycline such as doxycycline (first-line)
• Macrolide (clarithromycin or erythromycin) as alternative for penicillin-intolerant patients
• Respiratory fluoroquinolone (levofloxacin or moxifloxacin) as alternative

Non-Severe Influenza-Related Pneumonia

Most patients can be treated with oral antibiotics: 4, 1, 5

• Preferred: Co-amoxiclav or tetracycline orally
• Alternative: Macrolide or respiratory fluoroquinolone for penicillin-intolerant patients
• Parenteral options when oral contraindicated: IV co-amoxiclav or second/third generation cephalosporin (cefuroxime or cefotaxime) 4
• Timing: Administer antibiotics within 4 hours of admission 4
• Duration: 7 days for uncomplicated pneumonia 4

Severe Influenza-Related Pneumonia

Immediate parenteral antibiotics are required: 4, 1, 5

• Preferred regimen: IV broad-spectrum β-lactamase stable antibiotic (co-amoxiclav or cephalosporin) PLUS IV macrolide (clarithromycin or erythromycin) 4, 1
• Alternative: Respiratory fluoroquinolone with enhanced pneumococcal activity PLUS broad-spectrum β-lactamase stable antibiotic or macrolide 4
• Duration: 10 days for severe pneumonia; extend to 14-21 days if Staphylococcus aureus or Gram-negative enteric bacilli suspected/confirmed 4
• Transition to oral: Switch when clinical improvement occurs and temperature normal for 24 hours 4

Antibiotic Failure

For non-severe pneumonia on combination therapy: Change to fluoroquinolone with effective pneumococcal and staphylococcal coverage 4

For severe pneumonia not responding: Add antibiotics effective against MRSA 4

Common Pitfalls and Important Caveats

Avoid these errors:

• Do not delay antiviral treatment for laboratory confirmation—diagnose clinically 7, 8
• Do not use rapid influenza diagnostic tests (RIDTs) in hospitalized patients; use RT-PCR or molecular assays instead 1
• Do not routinely use corticosteroids for influenza treatment unless indicated for other reasons 1
• Do not administer immunoglobulin preparations for seasonal influenza 1
• Avoid aspirin in children due to Reye's syndrome risk 4

Enhance tolerability:

• Take oseltamivir with food to reduce nausea (occurs in ~10% of patients) 4, 3
• Manage nausea with mild antiemetics if needed 4

Monitor for complications:

• Investigate bacterial coinfection in patients with severe initial presentation, clinical deterioration after initial improvement, or failure to improve after 3-5 days of antiviral treatment 1, 5
• Staphylococcus aureus is more common during influenza outbreaks than in routine community-acquired pneumonia 5

Resistance monitoring:

• Watch for antiviral resistance in patients developing influenza while on/after neuraminidase inhibitor prophylaxis, immunocompromised patients with persistent viral replication, or severely ill patients not improving with treatment 1

Severity Assessment and Disposition

Use CRB-65 score for pneumonia severity: 4

• Score 1-2: Consider hospital referral and assessment
• Score ≥3: Urgent hospital admission
• Bilateral chest signs: Refer regardless of score
• Remember: CRB-65 does not replace clinical judgment 4