Some readers of our article on Antiviral Drugs for Seasonal Influenza have expressed concerns regarding our recommendation for use of the oral neuraminidase inhibitor oseltamivir (Tamiflu) to treat high-risk patients with confirmed or suspected influenza illness, citing the British Medical Journal and The Cochrane Collaboration, which have contended that there is no acceptable evidence that the drug prevents complications or hospitalizations and have questioned the completeness of the results of controlled trials conducted by the manufacturer (Roche).

View the Comparison Chart: Antiviral Drugs for Seasonal Influenza for 2024-2025

The oral polymerase acidic endonuclease inhibitor baloxavir marboxil (Xofluza — Genentech) is now FDAapproved for post-exposure prophylaxis of influenza in patients ≥12 years old. Baloxavir was approved for treatment of acute uncomplicated influenza in patients ≥12 years old in 2018.1 Two neuraminidase inhibitors are FDA-approved for prophylaxis of influenza: oseltamivir (Tamiflu, and generics) in patients ≥1 year old, and zanamivir (Relenza) in patients ≥5 years old.2 Unlike oseltamivir and zanamivir, baloxavir is not FDA-approved for pre-exposure prophylaxis of...

Zanamivir, a neuraminidase inhibitor taken by inhalation, has been approved by the FDA for treatment of influenza. Oseltamivir phosphate, an oral neuraminidase inhibitor, will probably be approved soon.

Healthcare providers are often asked if drugs can be used past their expiration date. Because of legal restrictions and liability concerns, manufacturers do not sanction such use and usually do not comment on the safety or effectiveness of their products beyond the date on the label. Since our last article on this subject, more data have become available.

Since publication of our recent article on antiviral drugs for influenza, increased levels of resistance to oseltamivir (Tamiflu) have been detected in influenza A H1N1 strains.

FluMist (MedImmune), the first live-attenuated and first intranasally administered influenza vaccine, has been approved by the FDA to prevent influenza in healthy people 5-49 years old. Given as a nasal spray, it stimulates immunity by viral replication in the upper respiratory tract. This vaccine apparently will be advertised directly to the public as a "needle-free" alternative to intramuscular influenza vaccine.

The FDA has approved peramivir (Rapivab – BioCryst), an IV neuraminidase inhibitor administered as a single dose, for treatment of acute uncomplicated influenza in patients ≥18 years old who have had symptoms for no more than 2 days. Peramivir was available temporarily in the US during the 2009-2010 influenza season under an emergency use authorization for treatment of hospitalized patients. It has been available in some Asian countries since 2010. Peramivir is the third neuraminidase inhibitor to be approved in the US. Oseltamivir (Tamiflu), which is taken orally, and zanamivir...

The FDA has approved baloxavir marboxil (Xofluza – Shionogi/Genentech), the first polymerase acidic (PA) endonuclease inhibitor, for single-dose, oral treatment of acute uncomplicated influenza in patients ≥12 years old. Baloxavir is the first drug with a new mechanism of action to be approved for treatment of influenza in almost 20 years.

The choice of drugs for treatment of pneumonia depends on the most likely pathogens causing the infection and local antimicrobial resistance patterns. Factors such as severity of illness, presence of co-morbid conditions and whether the infection is community or hospital-acquired also need to be considered.