LONDON, ENGLAND (NBC) - A new study raises questions about two drugs commonly used to fight influenza.
The study was conducted by the Cochrane Collaboration and published in the British Medical Journal.
Authors said there was insufficient evidence to support claims Tamiflu and the nasal spray Relenza reduced complications of influenza or flu-related hospital admissions.
Researchers also said Tamiflu could increase a person's risk of nausea and vomiting.
They found fewer adverse effects from Relenza compared to Tamiflu.
Flu experts are defending the drugs saying they're important weapons against the influenza.
Glaxosmithkline, which makes Relenza, and Roche, which makes Tamiflu, also challenged the review's conclusions.
The US government has spent over a billion dollars stockpiling flu anti-viral drugs.