What is the recommended treatment for influenza (flu)?

Treatment for Influenza (Flu)

Oral oseltamivir (Tamiflu) is the antiviral drug of choice for the treatment of influenza, administered twice daily for 5 days. 1

First-Line Treatment Options

Neuraminidase Inhibitors

• Oseltamivir (Tamiflu):

  • Adults and children >40kg: 75 mg twice daily for 5 days
  • Children (weight-based dosing):
    • ≤15 kg: 30 mg twice daily

    • 15-23 kg: 45 mg twice daily

    • 23-40 kg: 60 mg twice daily

    • Infants 0-8 months: 3 mg/kg twice daily 1, 2

• Zanamivir (Relenza):

  • Alternative for patients without chronic respiratory disease
  • 10 mg (two 5-mg inhalations) twice daily for 5 days
  • For patients ≥7 years 1, 3

• Peramivir (Rapivab):

  • IV option for patients who cannot take oral medication
  • Adults: 600 mg single IV infusion over 15-30 minutes
  • Children (2-12 years): 12 mg/kg (up to 600 mg maximum) 1

• Baloxavir (Xofluza):

  • Single oral dose based on weight for people ≥12 years who weigh >40 kg
  • 40-80 kg: one 40-mg dose
  • ≥80 kg: one 80-mg dose 1

Treatment Recommendations

When to Treat

Treatment should be offered as early as possible, regardless of influenza vaccination status, to:

1. Any hospitalized patient with suspected or confirmed influenza 1, 4
2. Patients with severe, complicated, or progressive illness 1
3. High-risk individuals including:
   • Children <2 years
   • Adults >65 years
   • Pregnant women
   • Persons with chronic medical conditions
   • Immunocompromised individuals 1, 4

Timing of Treatment

• Initiate treatment within 48 hours of symptom onset for maximum benefit 1, 4
• Treatment started within 24 hours of symptom onset provides the greatest benefit 5
• Treatment may still be beneficial when started after 48 hours in hospitalized patients or those with severe disease 6

Clinical Benefits of Treatment

• Reduces duration of uncomplicated influenza illness by approximately 1 day 1, 7
• May reduce risk of serious complications requiring antibiotics 1
• Decreases viral shedding 6
• Earlier treatment (within first 12 hours) can reduce total illness duration by up to 3.1 days compared to starting at 48 hours 5

Important Considerations

Administration

• Oseltamivir can be taken with food to improve gastrointestinal tolerability 2
• Patients using inhaled bronchodilators should use them before taking zanamivir 3

Side Effects

• Most common side effects of oseltamivir are nausea and vomiting, typically transient and occurring with first dosing 5
• Zanamivir should be avoided in patients with underlying respiratory conditions like asthma or COPD 1

Resistance Monitoring

• Emergence of resistance to oseltamivir during treatment is rare (<1% overall) 6
• Amantadine and rimantadine should not be used due to high levels of resistance 1

Supportive Care

• Maintain adequate hydration
• Consider acetaminophen for fever and symptom relief
• Rest until fever resolves 4

When to Consider Antibiotics

Antibiotics should not be routinely prescribed for uncomplicated influenza without evidence of bacterial co-infection. Consider antibiotics only if:

• Significant worsening of symptoms occurs
• Signs of pneumonia develop
• Patient has severe pre-existing illness 4

Follow-up Recommendations

Monitor for:

• Resolution of fever for at least 24 hours
• Improvement in respiratory symptoms
• Potential development of bacterial co-infection (worsening symptoms after initial improvement) 4

Advise patients to seek immediate medical attention if they experience:

• Difficulty breathing or shortness of breath
• Chest pain or pressure
• Sudden dizziness or confusion
• Severe or persistent vomiting 4