What is the recommended treatment for a patient who is influenza positive?

Treatment of Influenza-Positive Patients

Start oseltamivir 75 mg orally twice daily for 5 days immediately for all hospitalized patients, patients with severe/complicated/progressive illness, and all high-risk patients, regardless of timing of presentation. 1, 2, 3, 4

Who Gets Antiviral Treatment

Mandatory Treatment Groups (Start Immediately)

• All hospitalized patients with confirmed or suspected influenza 1, 2, 3
• Severe, complicated, or progressive illness regardless of risk factors 1, 2
• High-risk patients including:
  • Children <2 years (highest risk <6 months) 1, 3
  • Adults ≥65 years 1, 3
  • Pregnant women and postpartum (within 2 weeks) 1, 3
  • Chronic pulmonary disease (including asthma) 1, 3
  • Cardiovascular disease (except hypertension alone) 1, 3
  • Immunosuppression (medications or HIV) 1, 3
  • Diabetes mellitus or other metabolic disorders 1, 3
  • Neurologic/neurodevelopmental conditions 1, 3
  • Chronic renal or hepatic disease 1, 3

Optional Treatment (Clinical Judgment)

• Previously healthy outpatients presenting within 48 hours of symptom onset may benefit from shortened illness duration (approximately 24 hours reduction) 1, 2, 5, 6

Timing of Antiviral Initiation

The 48-Hour Rule Has Critical Exceptions

• Greatest benefit: Treatment started within 24-48 hours of symptom onset 1, 2, 6
• Still treat beyond 48 hours if:
  • Patient is hospitalized 1, 2, 3
  • Severe, complicated, or progressive illness 1, 2
  • Immunocompromised 1, 7, 3
  • High-risk patient with worsening symptoms 1

Never delay treatment while awaiting laboratory confirmation—clinical diagnosis is sufficient. 2, 3

Oseltamivir Dosing

Standard Adult Dosing

• Treatment: 75 mg orally twice daily for 5 days 2, 3, 4
• Prophylaxis: 75 mg orally once daily for 10 days (post-exposure) or up to 6 weeks (seasonal) 4

Pediatric Dosing (2 weeks to 12 years)

• Weight-based dosing from FDA label 4:
  • ≤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

Special Populations

• Renal impairment: Reduce to 75 mg once daily if CrCl <30 mL/min 4
• Pregnant women: Oseltamivir is safe and should be used when indicated 3
• Immunocompromised: May require extended treatment beyond 5 days if persistent viral replication 7

Alternative Antiviral: Zanamivir

• Zanamivir (inhaled) is an alternative neuraminidase inhibitor for patients unable to take oseltamivir 1, 2
• Absolute contraindication: Never prescribe zanamivir to patients with underlying airways disease (asthma, COPD) regardless of severity 3

Antibiotic Management: When to Add Antibacterials

Do NOT Routinely Give Antibiotics For:

• Previously healthy adults with uncomplicated influenza or acute bronchitis 1, 2, 3

Consider Antibiotics If:

• Worsening symptoms after initial improvement (recrudescent fever, increasing dyspnea) 1, 2
• High-risk patients with lower respiratory tract features 1, 2
• COPD or severe pre-existing illness 1

Immediate Antibiotics Required For:

• Confirmed or suspected influenza-related pneumonia 1, 2, 3

Antibiotic Regimens for Influenza-Related Pneumonia

Non-Severe Pneumonia (Outpatient)

• First-line: Co-amoxiclav (amoxicillin-clavulanate) or doxycycline 1, 2, 3
• Alternative: Macrolide (clarithromycin preferred over azithromycin for better H. influenzae coverage) 1
• Duration: 7 days 2

Severe Pneumonia (Hospitalized)

• Immediate IV combination therapy within 4 hours: 2, 3
  • IV co-amoxiclav OR 2nd/3rd generation cephalosporin (cefuroxime, cefotaxime)
  • PLUS macrolide (clarithromycin or erythromycin)
• Duration: 10 days for severe, microbiologically undefined pneumonia; 14-21 days if S. aureus or Gram-negative confirmed/suspected 2
• Switch to oral: When clinical improvement occurs, temperature normal for 24 hours, and oral route feasible 2

Critical: Always cover S. aureus when treating influenza-related pneumonia—this is a particularly lethal combination. 1, 2, 3

Supportive Care

• Antipyretics for fever control (acetaminophen or ibuprofen) 2
• Adequate hydration 2
• Absolute contraindication: Never use aspirin in children <16 years due to Reye syndrome risk 2, 3

Red Flags Requiring Immediate Re-evaluation

• Shortness of breath at rest 2
• Painful or difficult breathing 2
• Coughing up bloody sputum 2
• Recrudescent fever (fever returns after initial improvement) 1, 2
• Increasing dyspnea 2
• Altered mental status 2, 7
• Inability to maintain oral intake 2, 7

Critical Pitfalls to Avoid

• Never delay oseltamivir while awaiting laboratory confirmation 2, 3
• Never withhold oseltamivir from high-risk or hospitalized patients even if presenting beyond 48 hours 1, 2, 3
• Never rely on negative rapid antigen tests to rule out influenza—they have low sensitivity 3
• Never withhold antibiotics if bacterial superinfection is suspected—start empiric coverage immediately 7, 3
• Never forget S. aureus coverage in influenza-related pneumonia 2, 3
• Never use zanamivir in patients with asthma or COPD 3
• Never use aspirin in children with influenza 2, 3

Monitoring Parameters for Hospitalized Patients

• Vital signs (temperature, respiratory rate, pulse, blood pressure, oxygen saturation) at least twice daily 7
• Mental status 7
• More frequent monitoring if severe illness 7