What is the recommended treatment for influenza (flu)?

Treatment for Influenza (Flu)

Oral oseltamivir (Tamiflu) is the antiviral drug of choice for influenza treatment and should be started as soon as possible, ideally within 48 hours of symptom onset, with a standard dosage of 75 mg twice daily for 5 days in adults. 1

Antiviral Medication Options

First-line Treatment: Oseltamivir

• Adults: 75 mg twice daily for 5 days
• Children ≥12 months (based on weight):
  • ≤15 kg: 30 mg twice daily

  • 15-23 kg: 45 mg twice daily

  • 23-40 kg: 60 mg twice daily

  • 40 kg: 75 mg twice daily

• Infants 9-11 months: 3.5 mg/kg twice daily
• Term infants 0-8 months: 3 mg/kg twice daily 1, 2

Alternative Options:

• Inhaled zanamivir (Relenza): 10 mg (two 5-mg inhalations) twice daily for 5 days for patients ≥7 years without chronic respiratory disease 1, 3
• Intravenous peramivir (Rapivab): Single dose for patients ≥2 years who cannot take oral medication
  • Adults: 600 mg IV infusion over 15-30 minutes
  • Children (2-12 years): 12 mg/kg (max 600 mg) 1
• Baloxavir (Xofluza): Single oral dose for patients ≥12 years weighing >40 kg
  • 40-80 kg: 40 mg once
  • ≥80 kg: 80 mg once 1

Treatment Timing and Efficacy

The effectiveness of antiviral therapy is highly time-dependent:

• Maximum benefit: When started within 12 hours of symptom onset (reduces illness duration by 74.6 hours) 4
• Strong benefit: When started within 24 hours (reduces illness duration by 53.9 hours) 4, 5
• Moderate benefit: When started within 48 hours (reduces illness duration by approximately 24 hours) 6

Treatment Indications

Recommended for immediate treatment:

1. Hospitalized patients with confirmed or suspected influenza 1, 7
2. Patients with severe, complicated, or progressive illness 1
3. High-risk patients including:
   • Children <2 years
   • Adults ≥65 years
   • Pregnant or postpartum women (within 2 weeks of delivery)
   • Persons with chronic medical conditions (pulmonary, cardiovascular, renal, hepatic, hematologic, metabolic, or neurologic disorders)
   • Immunocompromised individuals 1

Consider treatment:

• Previously healthy outpatients with uncomplicated influenza if treatment can be initiated within 48 hours of symptom onset 1

Special Considerations

Treatment Beyond 48 Hours

• Treatment should be initiated even after 48 hours in:
  • Hospitalized patients
  • Patients with severe, complicated, or progressive illness
  • High-risk patients 1, 8

Antibiotic Use

• Not routinely recommended for previously well adults with uncomplicated influenza 1, 7
• Consider antibiotics for:
  • Patients with worsening symptoms (recrudescent fever, increasing dyspnea)
  • High-risk patients with lower respiratory features
  • Patients with suspected bacterial pneumonia 1, 7

Supportive Care

• Fever management with antipyretics (avoid aspirin in children)
• Adequate hydration
• Rest 1

Common Pitfalls to Avoid

1. Delaying treatment while waiting for laboratory confirmation - treatment decisions should be made clinically during influenza season 1

2. Missing the treatment window - earlier treatment provides significantly better outcomes; don't wait for test results if influenza is suspected 4, 5

3. Overlooking side effects - vomiting occurs in approximately 15% of children treated with oseltamivir (vs. 9% with placebo); taking medication with food can improve tolerability 1, 4

4. Inadequate treatment of high-risk patients - these patients benefit most from antiviral therapy and should receive treatment even if presenting after 48 hours 1

5. Unnecessary antibiotic use - antibiotics should be reserved for patients with suspected bacterial complications 1, 7