When to initiate antibiotic therapy if influenza symptoms do not improve?

From the Guidelines

Antibiotics should be considered if influenza symptoms do not improve after 3-5 days of initial empiric antimicrobial therapy or worsen after 48-72 hours, as recommended by the IDSA clinical practice guideline for acute bacterial rhinosinusitis in children and adults 1.

Key Considerations

• Most flu cases are viral and resolve without antibiotics within 1-2 weeks.
• Bacterial complications like pneumonia, sinusitis, or ear infections may develop and require antibiotic treatment.
• Common antibiotics prescribed include amoxicillin, amoxicillin-clavulanate, or azithromycin, depending on the specific complication.
• Contact your healthcare provider if you experience persistent fever over 101°F (38.3°C), difficulty breathing, chest pain, severe headache, confusion, or symptoms that improve then suddenly worsen.

Important Factors

• The use of antibiotics in adults with influenza not complicated by pneumonia is determined by the presence of any comorbid illnesses and the timing of first consultation with respect to the onset of symptoms 1.
• The potential advantage of delayed antibiotic prescription is to minimize rates of reconsultation, and it should come with clear instructions that the antibiotics should be used if the illness is not starting to settle after two days or if there is worsening of symptoms 1.
• The Infectious Diseases Society of America recommends considering the diagnosis of influenza in certain cases, including persons with fever and acute onset of respiratory symptoms, and administering antivirals within 48 hours of the onset of symptoms in patients with high-risk conditions or those who are not improving 1.

From the Research

Initiating Antibiotic Therapy for Influenza Symptoms

• Influenza is a viral infection, and antibiotics are ineffective against viral infections 2.
• Antibiotics should only be prescribed when there is evidence of a bacterial infection, such as pneumonia 2, 3.
• The decision to initiate antibiotic therapy should be based on clinical signs and symptoms, such as cough, fever, and nasal congestion, rather than solely on the presence of influenza-like illness 4.
• Studies have shown that antibiotics are often over-prescribed in patients with influenza or influenza-like illness, even in the absence of bacterial infection signs 2, 3.
• Neuraminidase inhibitors, such as oseltamivir, may be effective in reducing the risk of bacterial complications and the need for antibiotics in patients with influenza 2.

Clinical Predictors of Influenza Infection

• Cough and fever are the best multivariate predictors of influenza infection, with a positive predictive value of 79% 4.
• The presence of nasal congestion, headache, myalgia, and sore throat can also be indicative of influenza infection 4.
• The positive predictive value of these symptoms increases with the increase in temperature at the time of recruitment 4.

Antibiotic Prescribing for Acute Respiratory Infections

• Antibiotic overuse remains widespread in the treatment of outpatient acute respiratory infections, including among patients with laboratory-confirmed influenza 3.
• Targets for improved outpatient antibiotic stewardship include eliminating antibiotic treatment of viral upper respiratory tract infections and bronchitis, and improving adherence to prescribing guidelines for pharyngitis and sinusitis 3.
• Increased access to sensitive and timely virus diagnostic tests, particularly for influenza, may reduce unnecessary antibiotic use for these syndromes 3.