Influenza (Flu): Drug Therapy

Therapeutic targets

  • Alleviation of discomfort
  • Avoidance of complications

Therapy recommendations

  • In individuals without serious secondary diagnoses, only symptomatic therapy is required:
  • Caution. Acetylsalicylic acid (ASA) must not be used under any circumstances in children and adolescents, because there is a risk of so-called Reye’s syndrome. This disease is associated with brain and liver damage and is life-threatening for the affected children.
  • Antiviral therapy (antivirals) should be given as early as possible: within 48 hours of the onset of the first symptoms. Almost exclusively neuraminidase inhibitors are used.
  • Indications for antiviral therapy:
    • Suspicion of severe course
    • Increased risk of severe course (in case of pre-existing conditions, pregnancy).
  • Consider inpatient admission for complications (eg, viral pneumonia) and in multimorbid and elderly patients.
  • Postexposure prophylaxis (PEP) [see below].
  • See also under “Further therapy“.

Neuraminidase inhibitor

These drugs prevent new viral components from being released from cells already infected with the virus and infecting additional cells. The drug must be given no later than 48 hours after the first symptoms appear. It results in a shorter and less severe course of the disease while lowering the risk of life-threatening complications. Neuraminidase inhibitors are effective against influenza virus types A and B.

  • Mode of action: Inhibition of viral replication→ symptom duration (↓).
  • A recent Cochrane analysis shows that the agents have little effect in influenza and also fail to prevent complications
  • A 2015 meta-analysis attests to oseltamivir as having a specific effect, relieving influenza symptoms about a day earlier. The risk of lower respiratory tract infections requiring antibiotic therapy was reduced by 44% (4.9% versus 8.7%). The risk for hospitalization was reduced by 63% (0.6% versus 1.7%).
  • In hospitalized patients, mortality (death rate) could be reduced by two-thirds with oseltamivir (75 mg twice daily, 5 days) compared with non-treated patients.

Postexposure prophylaxis

Post-exposure prophylaxis is the provision of medication to prevent disease in individuals who are not protected against a particular disease by vaccination but have been exposed to it:

  • Antiviral chemoprophylaxis with antivirals (medications for viral infections) is given primarily to persons with health risks as described above. Use of the drugs zanamivir or oseltamivir should be started when increased influenza activity is detected and should then be continued until the end of the outbreak.
  • For example, if one person in a household becomes ill with influenza and another immunocompromised person is exposed as a result, the person should be prophylactically protected by taking antiviral medications (for 10 days).