Is intravenous (IV) fluid and paracetamol (acetaminophen) or nonsteroidal anti-inflammatory drugs (NSAIDs) more effective than oral paracetamol and hydration in reducing symptoms and duration of viral flu?

Intravenous Fluids and Antipyretics for Influenza Treatment: Evidence and Recommendations

There is insufficient evidence to support the use of intravenous (IV) fluids plus paracetamol/NSAIDs over oral antipyretics and home hydration for treating uncomplicated influenza. 1

Treatment Approach Based on Severity

For Uncomplicated Influenza (Outpatient Management)

• Oral antipyretics (paracetamol or NSAIDs) with adequate oral hydration is the recommended first-line symptomatic treatment 2
• Paracetamol should be used for fever and discomfort, continuing only while symptoms persist 2
• Adequate oral hydration (up to 2 liters daily) is recommended for symptom management 3, 2
• Antiviral treatment with oseltamivir should be considered for patients with:
  • Acute influenza-like illness with fever >38°C 1
  • Symptoms present for two days or less 1
  • High risk of complications (chronic medical conditions, immunocompromised status, age <2 or >65 years) 3, 2

For Severe Influenza Requiring Hospitalization

• IV fluids should be administered only when clinically indicated for volume depletion, not as routine therapy 1
• Patients should be assessed for volume depletion and need for additional intravenous fluids based on clinical presentation 1
• Hypoxic patients should receive appropriate oxygen therapy with monitoring of oxygen saturations 1
• Antiviral treatment with oseltamivir (75 mg twice daily for 5 days in adults) should be administered 3
• For children with severe illness, IV antibiotics providing coverage against S. pneumoniae, S. aureus, and H. influenzae should be considered 1

Evidence on Antipyretics in Influenza

• Randomized controlled trials have not demonstrated that IV paracetamol or NSAIDs are superior to oral formulations for symptom relief in influenza 4
• Paracetamol has been shown to reduce influenza-induced immunopathology in mouse models without compromising virus clearance or protective immunity 5
• A randomized controlled trial found that regular paracetamol had no effect on viral shedding, temperature, or clinical symptoms in patients with PCR-confirmed influenza 4
• Fixed-dose combinations of paracetamol with other agents have shown efficacy for symptomatic relief of common cold symptoms, but not specifically for influenza 6

Monitoring and Follow-up

• Patients should be advised to seek immediate medical attention if they develop:
  • Shortness of breath at rest or with minimal activity 3, 2
  • Painful or difficult breathing 3
  • Bloody sputum 3, 2
  • Drowsiness, disorientation, or confusion 3, 2
  • Fever persisting for 4-5 days without improvement 2
  • Initial improvement followed by recurrence of high fever 2

Important Considerations and Pitfalls

• There is no evidence that IV fluid administration with IV paracetamol/NSAIDs reduces duration of viral shedding or accelerates clinical recovery compared to oral treatment 4
• Hospitalization should be considered for patients with unstable vital signs (temperature >37.8°C, heart rate >100/min, respiratory rate >24/min, systolic BP <90 mmHg, O₂ saturation <90%) 1
• Overuse of IV fluids in patients who can maintain oral hydration may lead to unnecessary hospitalization and healthcare resource utilization 1
• Recent evidence raises questions about paracetamol's effect on glutathione levels, which might theoretically impact COVID-19 severity, but this has not been established for influenza 7

Conclusion for Clinical Practice

For most patients with uncomplicated influenza, oral antipyretics and adequate oral hydration provide appropriate symptomatic relief without the need for IV therapy. IV fluids and medications should be reserved for patients with clinical indications such as dehydration, inability to maintain oral intake, or severe illness requiring hospitalization.