Two drugs used to treat Influenza, Roche's Tamiflu and Glaxo's Relenza, are suspected to be responsible for some neurological problems seen in children. As such, a Food and Drug Administration panel on Friday recommended that the two manufacturers add new warnings about the psychiatric side effects. A formal decision will be taken at a later time.

"If the FDA concludes that it is valuable to place additional details on the label with regard to specific adverse event reports, then Roche is open to that consideration," the statement from Roche, which is headquartered in Basel, Switzerland, said.

The Food and Drug Administration said it received 115 reports of neuropsychiatric events associated with Relenza, with 81 reports coming from Japan. There were no reports of deaths, though. As far as Tamiflu is concerned, there were 596 reports of neuropsychiatric events and 16 neuropsychiatric-related deaths among children and adults possibly associated with the anti-viral drug by Roche.

"Although there is still uncertainty about the cause of the reported abnormal behavior, it seems prudent for the labeling for both products to contain language about post-marketing reports of hallucinations, delirium and abnormal behavior in the precautions section," the agency said in a memo.

Tamiflu, which contains oseltamivir, is used in the treatment and prophylaxis of both Influenzavirus A and Influenzavirus B. It is similar to Relenza, which contains zanamivir. Both substances prevent progeny virions from emerging from infected cells.

Earlier this year, Japan's Health Ministry warned that oseltamivir should not be given to children aged 10 to 19. The drug already included, since May 2004, information which includes warnings on neurological and psychological disorders as possible adverse effects, including: impaired consciousness, abnormal behavior, and hallucinations. The U.S. label only lists the potential for self-injury and delirium.