Before the announcement, the pharmaceutical giant had been in talks with the FDA regarding 103 cases under agency review in which Tamiflu users reported strange behavior, usually within a day of the drug's administration.
The majority of abnormal behavior cases have occurred in Japan -- where 24.5 million prescriptions for the drug were filled between 2001 and 2005 -- in patients younger than 17. Three people -- one a 14-year-old boy who had climbed on the roof of his family's condominium -- have fallen to their deaths after taking Tamiflu, says an FDA memo prepared Thursday at a pediatric advisory committee meeting. The memo also reports that an 8-year-old who took a single dose ran out the front door of his home in Japan half an hour later and would not respond to his name, instead just growling.
Tamiflu is known to cause fever and delirium, but Dr. Debra Birnkrant, director of the FDA's division of antiviral products, said it was not yet known if the drug or the flu itself were causing the abnormal behavior.
"Since there were a number of cases over the last year that we looked at, we thought it would be the prudent thing to make the public aware," she said, adding that another seasonal flu drug, amantadine, has also been associated with neurological side effects, although mostly in the elderly.
A statement released by Hoffman-La Roche said that reports of psychiatric side effects related to Tamiflu were uncommon. "While any relative contribution of Tamiflu to these events is unknown, Roche is committed to working closely with the FDA to ensure that the product label accurately reflects the reports," the statement said.
"It is interesting that only a few months ago the public was assured that Tamiflu was perfectly safe, and now it is being revealed that the drug may cause children to commit suicide," said Mike Adams, author of "How to Beat the Bird Flu." "It brings up the question: If the bird flu strikes, and Tamiflu is widely prescribed to the population, how crazy are things going to get if so many people are affected by suicidal tendencies?"
Tamiflu is intended to lessen the severity of flu symptoms or prevent the illness altogether, but countries across the globe -- including the United States -- are stockpiling it as a possible weapon against an H5N1 bird flu pandemic. H5N1 has killed 153 people worldwide since 2003, according to World Health Organization figures.