Oseltamivir, Zanamivir

Summary

Oseltamivir and zanamivir are antivirals that treat the influenza virus, commonly called the flu. They work by blocking neuraminidase, which prevents the release of new viral progeny. These drugs can treat Influenza A and B and have been shown to shorten the duration of illness if started within 48 hours of symptom onset.  Remember that nausea and vomiting are the most common side effects of Oseltamivir, while Zanamivir may exacerbate COPD or asthma.

Key Points

• Oseltamivir, Zanamivir
  • Oseltamivir is colloquially known by its trade name, Tamiflu
  • Mechanism
    • Inhibits neuraminidase
      • Neuraminidase cleaves viral progeny off of the cell surface allowing new viral particles to exit the cell
      • Oseltamivir and Zanamivir are sialic acid analogs that bind neuraminidase and thus inhibit viral progeny release
    • May also slow viral penetration of airway epithelium
  • Clinical Use
    • Influenza virus (flu)
      • Treats both influenza A and B infections
      • Beginning treatment within 48 hours of symptom onset can shorten course of illness
  • Adverse Effects
    • Gastrointestinal upset
      • Nausea and vomiting seen in ~15% of patients
    • Zanamivir may exacerbate COPD and asthma
      • Related to its route of administration as an inhaled dry powder