Oseltamivir: the real world data

Oseltamivir has become a mainstay in the treatment of influenza, although there is no evidence from clinical trials that it reduces mortality.1 In 2009 we published a review of observational studies examining the effects of oseltamivir in influenza. It was based on a list of studies provided by Roche, the manufacturer, that it claimed provided evidence of the drug’s “real life” value.2 The evidence supported a role for oseltamivir in reducing pneumonia and other complications of influenza in otherwise healthy adults. But we found no evidence that it was associated with mortality, little information on safety, and none on pregnancy related outcomes. We have now updated our evidence by doing a systematic search of published observational studies. Here we explain the advantages and drawbacks of observational data and what they tell us about oseltamivir.

Worldwide influenza is a major public health concern. During an epidemic about 5-15% of the global population develop an upper respiratory tract infection, 3 to 5 million people contract severe disease, and there are between 250 000 and 500 000 influenza related deaths.3 Vaccination is the leading public health control measure to prevent disease and reduce the effect of epidemics, but neuraminidase inhibitors (oseltamivir or zanamivir) or M2 ion channel blockers (amantadine or rimatidine) may be prescribed to reduce the duration of symptoms and improve clinical outcomes. The use of neuraminidase inhibitors increased substantially during the 2009 pandemic of influenza A/H1N1, partly because there was no effective vaccine but also because of concerns over increasing drug resistance to amantadine and rimatidine.3