What antiviral therapy is recommended for a critically ill patient with a confirmed or suspected viral infection, such as COVID-19 (Coronavirus Disease 2019) or influenza, in the Intensive Care Unit (ICU)?

Antiviral Therapy for Critically Ill ICU Patients

For critically ill patients with confirmed COVID-19 in the ICU, remdesivir is recommended for those requiring supplemental oxygen but not yet on invasive mechanical ventilation, administered as 200 mg IV loading dose on day 1 followed by 100 mg IV daily for up to 10 days. 1, 2

COVID-19 Antiviral Treatment

Remdesivir Dosing and Indications

Remdesivir should be initiated as soon as possible after COVID-19 diagnosis in hospitalized patients requiring oxygen support but not yet mechanically ventilated. 1, 2

• Loading dose: 200 mg IV on Day 1 2
• Maintenance dose: 100 mg IV once daily from Day 2 2
• Duration for mechanically ventilated patients: 10 days total 2
• Duration for non-ventilated hospitalized patients: 5 days, extendable to 10 days if no clinical improvement 2

Evidence for Remdesivir Efficacy

The evidence shows modest but meaningful benefits in critically ill patients:

• Remdesivir reduces median time to recovery from 15 days to 10 days in hospitalized patients (recovery rate ratio 1.29,95% CI 1.12-1.49, p<0.001) 2
• Among patients with severe disease at enrollment, median recovery time was 11 days versus 18 days with placebo (recovery rate ratio 1.31,95% CI 1.12-1.52) 2
• The Infectious Diseases Society of America notes remdesivir "probably makes little or no difference to mortality but increases chance of clinical improvement slightly and decreases risk of clinical worsening within 28 days" 1

Critical Limitations and Contraindications

Do not continue remdesivir in patients who progress to mechanical ventilation beyond the initial treatment course, as no benefit has been demonstrated. 1

Paxlovid (nirmatrelvir/ritonavir) is NOT recommended for critically ill ICU patients with COVID-19. 1

Lopinavir/ritonavir should NOT be used—the Surviving Sepsis Campaign specifically suggests against its routine use based on trial data showing no benefit. 3, 1

Influenza Antiviral Treatment

Oseltamivir for Confirmed Influenza

If influenza is confirmed by PCR testing of nasopharyngeal or respiratory secretions, treat with oseltamivir according to standard guidelines. 3

Do not use oseltamivir for COVID-19, as it has no activity against coronaviruses. 1

Co-infection Considerations

Co-infection rates with influenza in COVID-19 patients are low (approximately 4-5%), so rapidly de-escalate empirical anti-influenza therapy based on negative testing and clinical response. 1

Monitoring Requirements Before and During Antiviral Therapy

Perform hepatic laboratory testing before starting remdesivir and monitor while receiving treatment as clinically appropriate. 2

Determine prothrombin time before starting remdesivir and monitor during treatment as clinically appropriate. 2

Administration Requirements

Remdesivir may only be administered in settings where healthcare providers have immediate access to medications to treat severe infusion or hypersensitivity reactions, such as anaphylaxis, and the ability to activate the emergency medical system. 2

Administer remdesivir by intravenous infusion only—do not administer by any other route. 2

Empirical Antibiotics in Critically Ill Patients

While not strictly antiviral therapy, critically ill patients often require empirical antibiotics:

In mechanically ventilated patients with COVID-19 and respiratory failure, use empiric antimicrobials/antibacterial agents, then assess for de-escalation daily based on microbiology results and clinical status. 3

Critically ill COVID-19 patients, including those admitted to ICU or mechanically ventilated, have higher risk of acquiring bacterial infections and may require antibiotic use. 3

For pulmonary bacterial co-infections in critically ill or ICU patients, consider empirical add-on anti-MRSA antibiotics in selected cases. 3

For pulmonary secondary bacterial infections in critically ill or ICU settings, double antipseudomonal antibiotics and/or anti-MRSA antibiotics may be prescribed based on local epidemiology. 3

Common Pitfalls to Avoid

Do not routinely prescribe antibiotics to every COVID-19 patient—base prescription on clinical justifications such as disease manifestations, disease severity, radiographic imaging, and laboratory data. 3

Do not use serum biomarkers alone (WBC, CRP, PCT) to decide when to start antimicrobials, especially when the patient is not critically ill. 3

Do not routinely administer antibiotics for COVID-19 patients receiving immunomodulatory agents (corticosteroids, IL-6 inhibitors), given weak evidence these agents predispose to secondary bacterial infections. 3