Researchers called into question the effectiveness of Roche's anti-viral drug Tamiflu and GlaxoSmithKline's Relenza, and even suggested governments that stockpile the medicine are "wasting billions of dollars."
"There is no credible way these drugs could prevent a pandemic," Carl Heneghan, one of the lead investigators of the review and a professor of evidence-based medicine at Britain's Oxford University told Reuters.
The Cochrane Review research team determined the medicine could shorten flu symptoms by about half a day, but they did not find evidence the drugs "cut hospital admissions or lessen complications of the disease," Reuters reported.
"There is no credible way these drugs could prevent a pandemic," Heneghan, said.
The researchers also found harmful side effects that had not been noticed in past trials.
"Remember, the idea of a drug is that the benefits should exceed the harms," Heneghan said. "So if you can't find any benefits, that accentuates the harms."
People who took Tamiflu were at risk of developing symptoms such as "nausea, vomiting, and kidney problems," as well as mental symptoms such as "paranoia, nervousness, thoughts about suicide, and hallucinations," the BMJ group reported via WebMD.
Roche stated that it "fundamentally disagrees with the overall conclusions," but they have not allowed the Chochrane Review unrestricted access to Tamiflu data in the past, Reuters reported.
"We firmly stand by the quality and integrity of our data ... and subsequent real-world evidence demonstrating that Tamiflu is an effective medicine in the treatment and prevention of influenza," it said in a statement, Reuters reported.
Tamiflu is stockpiled in many countries and is even on the World Health Organization's "essential medicines" list.
The researchers reviewed 20 trials of Tamiflu and 26 trials of Relenza to make their findings.
"[Money spent of stockpiles] has been thrown down the drain" Heneghan said. The U.S. alone has spent more than $1.3 billion on these flu drugs.
"The original evidence presented to government agencies around the world was incomplete," Fiona Godlee, editor of the British Medical Journal, told Reuters. "And when they (the Cochrane review team) eventually received the full information on these drugs, the complete evidence gives a very much less positive picture."
