New Meta-Analysis Clarifies Oseltamivir's Benefits and Risks

Summary and Comment |
February 5, 2015

New Meta-Analysis Clarifies Oseltamivir's Benefits and Risks

  1. Bruce Soloway, MD

A patient-level meta-analysis confirms this drug's modest antiviral activity and substantial side effects.

  1. Bruce Soloway, MD

In a 2014 Cochrane meta-analysis of eight manufacturer-conducted, placebo-controlled, influenza treatment trials in adults, researchers concluded that oseltamivir (Tamiflu) “modestly reduces” duration of symptoms but causes nausea and vomiting and, possibly, adverse psychiatric effects. The report pointedly questioned the antiviral activity of oseltamivir and “its use in clinical practice as an anti-influenza drug” (NEJM JW Gen Med May 15 2014 and BMJ 2014; 348:g2545). However, the analysis was based on aggregate rather than patient-level data.

Researchers now report a meta-analysis of patient-level data from the same trials plus one recent addition (total of 4328 adult patients with flu-like illness). In all trials, patients with fever and at least two influenza symptoms of shorter than 36 hours' duration were treated with oseltamivir (75 mg) or placebo twice daily for 5 days. Roche provided all data and unrestricted funding for the analysis.

Among 2893 patients with confirmed influenza, median time to alleviation of all symptoms was significantly shorter in those who received oseltamivir than in those who received placebo (98 vs. 123 hours), and oseltamivir patients experienced significantly fewer lower respiratory complications and hospitalizations (1 fewer per 100 treated patients). Among all patients with flu-like illness, the difference between groups in time to symptom alleviation was attenuated but still statistically significant. Among patients who were found to be uninfected with influenza, outcomes were similar for the oseltamivir and placebo groups. Patients taking oseltamivir experienced significantly more nausea and vomiting (5 more patients with vomiting per 100 treated patients) but no excess psychiatric symptoms.


This analysis confirms oseltamivir's antiviral activity, its modest effect on duration of influenza symptoms, and its substantial side effects. Ideally, treatment with oseltamivir should be limited to patients with confirmed influenza, with careful evaluation of potential benefits and harms.

Editor Disclosures at Time of Publication

  • Disclosures for Bruce Soloway, MD at time of publication Nothing to disclose


Reader Comments (2)


As someone who gets the flu all too frequently, I am hopeful that a better treatment will soon be forthcoming. I developed pneumonia while travelling in China which seem to have led to chronic bronchitis, a diagnosis made by a pulmonologist this year. I wonder if the pneumonia is a causative factor in this diagnosis.

MB.BS Physician, Internal Medicine, Health Canada

The Lancet paper was particularly timely given the relative inefficacy of this years Flu. vaccine.

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