What is the recommended treatment for influenza (flu)?

Treatment of Influenza (Flu)

The recommended first-line treatment for influenza is oseltamivir (Tamiflu) 75 mg twice daily for 5 days in adults, with treatment ideally initiated within 48 hours of symptom onset. 1

Antiviral Medication Options

Oseltamivir (Tamiflu)

• First-line treatment for both influenza A and B
• Dosing for adults: 75 mg twice daily for 5 days 2
• Pediatric dosing (weight-based) 1, 2:
  • ≤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

• Can be taken with food to enhance tolerability 2
• Reduces illness duration by approximately 24 hours when started within 48 hours 3, 4

Alternative Antivirals

• Zanamivir (Relenza): 10 mg (two 5-mg inhalations) twice daily for 5 days 5
  • For patients ≥7 years without underlying respiratory disease
  • Administered via oral inhalation only
  • Not recommended for patients with underlying respiratory conditions due to risk of bronchospasm

Treatment Algorithm

1. Initiate treatment as soon as possible:

   • Optimal benefit when started within 24-48 hours of symptom onset 6
   • Do not delay treatment while awaiting test results 6

2. Patient assessment for treatment:

   • Treat all patients with:

     • Confirmed or suspected influenza requiring hospitalization
     • Severe, complicated, or progressive illness
     • High-risk factors (children <2 years, adults ≥65 years, pregnant women, chronic medical conditions) 6, 1

   • Consider treatment for:

     • Otherwise healthy patients with uncomplicated influenza if within 48 hours of symptom onset 6

3. Treatment duration:

   • Standard course: 5 days for uncomplicated influenza 6, 2
   • May consider longer treatment for severely ill or immunocompromised patients 6

Supportive Care

• Fever management with antipyretics (avoid aspirin in children) 1
• Adequate hydration and rest 1
• Monitor for worsening symptoms that may indicate complications 6

Antibiotic Use

• Antibiotics are not routinely indicated for uncomplicated influenza or acute bronchitis complicating influenza 6
• Consider antibiotics only for:
  • Patients with worsening symptoms (recrudescent fever, increasing dyspnea) 6
  • High-risk patients with lower respiratory symptoms 6
  • Suspected bacterial complications 1

Special Considerations

• Patients unable to mount a febrile response (immunocompromised, elderly) may still benefit from antiviral treatment despite lack of documented fever 6
• Hospitalized patients may benefit from antiviral treatment even if started >48 hours from symptom onset 6
• Adjust oseltamivir dosage in patients with renal impairment 2

Common Pitfalls to Avoid

1. Delaying treatment while waiting for laboratory confirmation - treatment decisions should be made clinically during influenza season 1
2. Unnecessary antibiotic use - reserve for suspected bacterial complications 6, 1
3. Missing treatment windows - greatest benefit occurs when treatment is started within 48 hours, but later treatment can still be beneficial in severe cases 6
4. Overlooking high-risk patients who may not present with typical symptoms, especially the elderly or immunocompromised 6

The evidence consistently shows that early antiviral treatment reduces the duration of influenza symptoms by approximately 24 hours in otherwise healthy patients 3, 4, 7 and may reduce the risk of serious complications, particularly in high-risk populations.