Tamiflu's Effectiveness Doubted

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.
"This benefit has been generalized to assume benefit for very ill people in
hospital," the authors write. Although this seems reasonable, they say they
have no data to support this.
The data on the effectiveness of Tamiflu against complications of the flu
are "confusing," the researchers write. The researchers had to drop eight
trials that were never fully published, although they were included
in the previous review. But the researchers dropped them for this review
because they could not verify the results independently.
Del Mar's bottom-line advice for healthy people? "Don't take [the
antivirals] to prevent complications because we don’t have enough good data for
that. It reduces the [duration of the] illness by one day. So you have to make
a decision about whether it’s worth it or not."
A viable alternative, he tells WebMD, may be to take acetaminophen or "lemon sips"
-- a hot lemon drink.
http://www .webmd.com/cold-and-flu/news/20091209/tamiflu-effectiveness-doubted?src=RSS_PUBLIC