Some readers of our article on Antiviral Drugs for Seasonal Influenza1 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).2
Randomized controlled trials, mainly in patients with mild influenza illness, have shown that treatment with oseltamivir or zanamivir (Relenza), an inhaled neuraminidase inhibitor, started within 48 hours of the onset of illness can shorten the duration of symptoms by about one day. Most controlled trials of the effectiveness of these drugs in preventing pneumonia or other serious complications of influenza have not been powered adequately to provide convincing evidence of efficacy, but a broad consensus of expert clinicians has interpreted the combined results of controlled trials, observational studies, and meta-analyses as showing that early antiviral treatment of high-risk patients with influenza can reduce the risk of complications such as pneumonia, respiratory failure, and death.3,4
Influenza kills about 50,000 patients annually in the US. Oseltamivir and zanamivir are generally well tolerated, and there is no alternative treatment. (Since this article was first posted online, peramivir (Rapivab), an IV neuraminidase inhibitor, has been approved by the FDA. It will be reviewed in our February 2, 2015 issue.)
- Antiviral drugs for seasonal influenza 2014-2015. Med Lett Drugs Ther 2014; 56:121.
- T Jefferson et al. Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database Syst Rev 2014; 4:CD008965.
- CDC. Influenza antiviral medications: summary for clinicians. Available at http://www.cdc.gov. Accessed December 23, 2014.
- IDSA. Statement by the Infectious Disease Society of America (IDSA) on the recent publication on "Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children." April 2014. Available at: http://www.idsociety.org. Accessed December 23, 2014.