What are the treatment options for Influenza (flu)?

From the Guidelines

Influenza treatment should be initiated as soon as possible with antiviral medications, such as oseltamivir, zanamivir, or peramivir, for patients with confirmed or suspected influenza, especially those at high risk of complications, including the elderly, young children, pregnant women, and those with chronic medical conditions. The treatment should ideally start within 48 hours of symptom onset, but it may still be beneficial when started later in patients with severe, complicated, or progressive illness and in hospitalized patients 1.

Recommended Antiviral Medications

• Oseltamivir (Tamiflu) 75mg twice daily for 5 days
• Zanamivir (Relenza) 10mg inhaled twice daily for 5 days
• Peramivir (Rapivab) as a single IV dose of 600mg
• Baloxavir (Xofluza) as a single oral dose based on weight (40mg for patients 40-80kg, 80mg for those over 80kg)

Supportive Care

• Acetaminophen or ibuprofen for fever and pain
• Plenty of fluids to prevent dehydration
• Adequate rest

High-Risk Individuals

• Children younger than 2 years
• Adults ≥65 years
• Pregnant women and those within 2 weeks postpartum
• Persons with chronic medical conditions, such as chronic pulmonary, cardiovascular, renal, hepatic, hematological, or metabolic disorders
• Immunocompromised patients

Duration of Treatment

• Uncomplicated influenza: 5 days
• Severe or complicated influenza: may require longer duration of treatment, especially in patients with immunocompromising conditions or those requiring hospitalization 2.

It is essential to note that antiviral treatment should not be delayed while awaiting diagnostic test results, and empiric treatment is often necessary 3. Clinicians should use their judgment when making treatment decisions, considering factors such as disease severity, age, underlying medical conditions, likelihood of influenza, and time since onset of symptoms 4.

From the FDA Drug Label

Oseltamivir phosphate for oral suspension is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. RELENZA is a prescription medicine used to: • treat the flu (influenza A and B virus) in people who are aged 7 years and older who have had flu symptoms for no more than 2 days • help prevent the flu in people who are aged 5 years and older.

Influenza Treatment Options:

• Oseltamivir (PO) is indicated for the treatment of influenza A and B in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours 5.
• Zanamivir (INH) is indicated for the treatment of influenza A and B in people aged 7 years and older who have had flu symptoms for no more than 2 days 6. Key Considerations:
• Oseltamivir is not recommended for patients with end-stage renal disease not undergoing dialysis 5.
• Zanamivir is not recommended for the treatment or prevention of the flu in people with breathing problems, such as asthma and chronic obstructive pulmonary disease (COPD) 6.

From the Research

Influenza Treatment Options

• Oseltamivir is a prodrug of oseltamivir carboxylate, a potent and selective inhibitor of the neuraminidase glycoprotein essential for replication of influenza A and B viruses 7
• Studies have shown that oseltamivir reduces the duration of the disease by up to 1.5 days and the severity of illness by up to 38% compared with placebo when initiated within 36 hours of symptom onset 7
• A liquid formulation of oseltamivir has been shown to be effective in the treatment of children with influenza 7

Efficacy of Oseltamivir Treatment

• Oseltamivir treatment resulted in a modest reduction in the duration of symptoms and virus shedding in people with uncomplicated influenza infections, even when treatment was started 48 h or longer after illness onset 8
• The median duration of symptoms was shorter in the oseltamivir group (3 days) than in the placebo group (4 days) 8
• Oseltamivir significantly reduced virus isolation on days 2, 4, and 7 in participants enrolled less than 48 h since illness onset 8

Diagnosis and Treatment of Influenza

• Treatment with one of four approved anti-influenza drugs may be considered if the patient presents within 48 hours of symptom onset 9
• The benefit of treatment is greatest when antiviral therapy is started within 24 hours of symptom onset 9
• Annual influenza vaccination is recommended for all people six months and older who do not have contraindications 9

Antiviral Therapies for Influenza

• Early initiation, preferably within 48 h of symptom onsets, of antiviral treatments with NAI and baloxavir, is crucial to produce favourable outcomes in patients with influenza infection 10
• Updated evidence does not suggest routine use of combined antiviral agents in patients with influenza infection 10
• Treatment-emergent resistant influenza variants may occur during NAI and baloxavir use, but it has no major impact on subsequent recovery 10