What are the recommendations for outpatient management of influenza?

Outpatient Management of Influenza

Antiviral treatment should be started as soon as possible for patients with suspected or confirmed influenza, particularly those at high risk of complications, using a single neuraminidase inhibitor such as oral oseltamivir, inhaled zanamivir, or intravenous peramivir. 1

Patient Selection for Antiviral Treatment

High Priority for Treatment (Start Antivirals Regardless of Duration)

• Outpatients at high risk of influenza complications, including those with chronic medical conditions and immunocompromised patients 1
• Children younger than 2 years and adults ≥65 years 1
• Pregnant women and those within 2 weeks postpartum 1
• Outpatients of any age with severe or progressive illness 1

Consider Treatment

• Otherwise healthy adults and children not at high risk of complications 1
• Treatment is most effective when started within 48 hours of symptom onset, but may still be beneficial when started later in high-risk patients 2

Recommended Antiviral Medications

First-Line Treatment

• Oseltamivir (Tamiflu): The antiviral drug of choice for outpatient management 1
  • Adults and adolescents ≥13 years: 75 mg twice daily for 5 days 3
  • Children (based on weight) 1, 3:
    • ≤15 kg: 30 mg twice daily for 5 days

    • 15-23 kg: 45 mg twice daily for 5 days

    • 23-40 kg: 60 mg twice daily for 5 days

    • 40 kg: 75 mg twice daily for 5 days

  • Infants 9-11 months: 3.5 mg/kg twice daily for 5 days 1
  • Term infants 0-8 months: 3 mg/kg twice daily for 5 days 1

Alternative Treatments

• Zanamivir (Relenza): For patients who cannot tolerate oseltamivir 1

  • Adults and children ≥7 years: 10 mg (two 5-mg inhalations) twice daily for 5 days 1
  • Not recommended for patients with underlying respiratory disease 1

• Peramivir (Rapivab): For patients who cannot absorb oral medication 1

  • Adults: One 600-mg IV infusion 1
  • Children (2-12 years): One 12 mg/kg dose via IV infusion 1
  • Children (13-17 years): One 600 mg dose via IV infusion 1

• Baloxavir: For patients ≥12 years 1

  • 40-80 kg: one 40-mg dose orally
  • ≥80 kg: one 80-mg dose orally

Dosage Adjustments for Renal Impairment

• For moderate renal impairment (CrCl >30-60 mL/min): Reduce oseltamivir to 30 mg twice daily 3
• For severe renal impairment (CrCl >10-30 mL/min): Reduce oseltamivir to 30 mg once daily 3
• Not recommended for ESRD patients not on dialysis 3

Management of Complications

Bacterial Co-infection

• Investigate and empirically treat bacterial co-infection in patients with 1:
  • Severe disease (extensive pneumonia, respiratory failure, hypotension, fever)
  • Clinical deterioration after initial improvement, particularly in those treated with antivirals
  • Failure to improve after 3-5 days of antiviral treatment

Monitoring Response to Treatment

• Patients should show clinical improvement within 48 hours of starting treatment 1
• Failure to improve within 48 hours should prompt clinical reassessment 1
• Consider investigating other causes besides influenza in patients who fail to improve or deteriorate despite antiviral treatment 1

Supportive Care

• Adequate hydration (drinking plenty of fluids) 2
• Symptomatic treatment of fever with acetaminophen or ibuprofen 2
• Rest and isolation to prevent transmission 2

Special Considerations

Antiviral Resistance

• Consider resistance testing in patients with 1:
  • Immunocompromising conditions and evidence of persistent viral replication
  • Severe influenza who do not improve with treatment and have evidence of persistent viral replication
  • Laboratory-confirmed influenza who received subtherapeutic dosing

Corticosteroids

• Do not administer corticosteroid adjunctive therapy for the treatment of influenza unless clinically indicated for other reasons 1

Chemoprophylaxis Recommendations

• Consider antiviral chemoprophylaxis for 1:
  • High-risk patients for whom influenza vaccine is contraindicated
  • High-risk patients during the 2 weeks after vaccination, before optimal immunity is achieved
  • Unvaccinated family members or healthcare personnel with likely ongoing exposure to unvaccinated high-risk patients
  • Prophylaxis dosing is typically once daily for 10 days following exposure 1, 3

Common Pitfalls to Avoid

• Delaying treatment while waiting for laboratory confirmation 1, 4
• Starting treatment beyond 48 hours in low-risk patients (minimal benefit) 5, 6
• Using higher than approved doses of neuraminidase inhibitors (not recommended) 1, 7
• Administering combination neuraminidase inhibitor therapy (not recommended) 1
• Failing to consider bacterial co-infection in patients with deteriorating condition 1