Tamiflu's Effectiveness Doubted
Expert Analysis Concludes Antiviral Drug May Not Prevent Complications in Healthy People
Dec. 9, 2009 -- Widely used antiviral drugs such as Tamiflu and Relenza may not prevent complications such as pneumonia in healthy people, according to a new investigation and analysis.
"We're not so sure the drugs are so magic a bullet as we previously thought," researcher Chris Del Mar, MD, dean of medicine at Bond University in Australia, tells WebMD. He is the coordinating editor of the Cochrane Acute Respiratory Infections Group and headed the research team that analyzed 20 published trials that focused on prevention, treatment, and adverse reactions of the antiviral drugs against the flu, known as neuraminidase inhibitors. The Cochrane Collection regularly updates evidence for and against the effectiveness of specific treatments.
The study is published in BMJ Online First, and the investigation developed into a joint project of BMJ and the U.K.'s Channel 4 news.
"Cochrane decided to update all the reviews that might inform influenza management," Del Mar tells WebMD. The use of the drugs has increased dramatically since the swine flu pandemic began in April 2009. Worldwide, governments have stockpiled Tamiflu to prepare for a pandemic.
The investigation, Del Mar says, was hampered by a scarcity of good data from the authors of the study and from Roche, the company that makes Tamiflu.
But Roche, in a statement, says it stands behind the integrity of the data, which supports the use and effectiveness of Tamiflu.
Tamiflu Effective? Review Details
Del Mar's team set out to update a 2005 Cochrane Library review that evaluated the effect of the drugs in preventing or improving influenza symptoms, transmission of the flu, and complications from the flu in healthy people and to estimate the effect of adverse effects.
"We found that the information we had wasn't as good as we initially thought when we first did the review," Del Mar says. "We were surprised at how poor the data [was ] on adverse effects."
They concluded that the neuraminidase inhibitors have "modest effectiveness against the symptoms of influenza in otherwise healthy adults." The drugs reduce the duration of illness by about a day.