What is the recommended treatment for influenza?

Treatment of Influenza

The recommended first-line treatment for influenza is a neuraminidase inhibitor (NAI), specifically oral oseltamivir, inhaled zanamivir, or intravenous peramivir, started as soon as possible after symptom onset. 1

Patient Selection for Antiviral Treatment

Antiviral treatment should be initiated for:

1. High priority patients (treatment should be started regardless of illness duration):

   • Hospitalized patients with confirmed or suspected influenza 1
   • Patients with severe, complicated, or progressive illness 1
   • Patients at high risk for influenza complications:
     • Children <2 years of age 1
     • Adults ≥65 years 1
     • Pregnant women and those within 2 weeks postpartum 1
     • Persons with chronic medical conditions (pulmonary, cardiovascular, renal, hepatic, hematological, metabolic disorders) 1
     • Immunocompromised individuals 1
     • Morbidly obese individuals (BMI ≥40) 1
     • American Indians/Alaska Natives 1
     • Residents of nursing homes and chronic-care facilities 1
     • Children on long-term aspirin therapy 1

2. Consider treatment for otherwise healthy outpatients with uncomplicated influenza 1

Recommended Antiviral Medications

First-line treatment:

• Oseltamivir (Tamiflu) - oral administration 1, 2

  • Adults and adolescents ≥13 years: 75 mg twice daily for 5 days 3
  • Children (based on weight) 3:
    • ≤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

  • Available as capsules or oral suspension (6 mg/mL) 3

• Zanamivir (Relenza) - inhaled administration 1, 2

  • 10 mg (two 5-mg inhalations) twice daily for 5 days 2
  • Not recommended for patients with underlying respiratory disease 2

• Peramivir (Rapivab) - intravenous administration 1, 2

  • Single 600 mg IV infusion 2

Alternative treatment:

• Baloxavir - oral administration 2
  • For people ≥12 years weighing >40 kg
  • Single dose based on weight:
    • 40-80 kg: 40 mg
    • ≥80 kg: 80 mg

Timing of Treatment

• Start treatment as soon as possible after symptom onset 1, 2
• Greatest benefit when started within 48 hours of symptom onset 1, 4
  • Treatment within 12 hours after onset reduces illness duration by an additional 74.6 hours compared to starting at 48 hours 4
  • Treatment within 24 hours reduces illness duration by an additional 53.9 hours compared to starting at 48 hours 4
• Do not delay treatment while awaiting test results for patients with suspected influenza who are severely ill or at high risk for complications 1
• Treatment may still be beneficial when started after 48 hours in hospitalized patients or those with severe or progressive illness 1, 5

Duration of Treatment

• Standard duration: 5 days for uncomplicated influenza in otherwise healthy patients 1
• Consider longer duration for:
  • Immunocompromised patients 1
  • Patients requiring hospitalization for severe lower respiratory tract disease 1
  • Patients with persistent viral replication 1

Management of Complications

• Investigate and empirically treat bacterial coinfection in patients who:

  • Present initially with severe disease (extensive pneumonia, respiratory failure, hypotension, fever) 1
  • Deteriorate after initial improvement, particularly those treated with antivirals 1
  • Fail to improve after 3-5 days of antiviral treatment 1

• Consider alternative diagnoses in patients who fail to improve or deteriorate despite antiviral treatment 1

Special Considerations

• Gastrointestinal side effects (nausea, vomiting) may occur with oseltamivir in approximately 10-15% of patients 1, 4

  • Taking medication with food may improve tolerability 4
  • Symptoms are typically mild and transient, resolving within 1-2 days 4

• Resistance testing should be considered for:

  • Patients who develop influenza while on NAI prophylaxis 1
  • Immunocompromised patients with persistent viral replication despite treatment 1
  • Patients who received subtherapeutic NAI dosing 1
  • Patients with severe influenza who don't improve with NAI treatment 1

• Corticosteroid adjunctive therapy should not be administered for treatment of influenza 1

By following these evidence-based recommendations for influenza treatment, clinicians can reduce symptom duration, decrease the risk of complications, and potentially reduce mortality in high-risk populations.