The US Food and Drug Administration (FDA) Pediatric Advisory Committee recommended to the agency yesterday, Tuesday 27th November, that makers of the flu drug Tamiflu be urged to change the drug’s warning label to include the fact that the psychiatric symptoms experienced by children on the drug could be caused by having the flu.

Tamiflu (oseltamivir) is made by the Swiss drug company Roche Holding AG, and has been used by 48 million patients worldwide since it hit the market in 1999 to reduce the severity and duration of influenza symptoms.

A spokeswoman for the company told the Associated Press news agency that the company had accepted the recommendation. She pointed out that patients with serious flu symptoms are at risk of psychiatric problems from the flu itself, whether taking the drug or not.

She said the company has conducted trials into the drug’s side effects and found no causal relationship between Tamiflu and “reported cases of delirium and hallucinations”. Flu can take the body’s temperature to 104 Fahrenheit (40 Celsius) and higher, and people needed to know that this condition alone is linked to delirium and hallunication.

According to a report in WebMD, the FDA panel’s vote was 8 to 6, and reflected the agency’s uncertainty about whether the drug or the condition led to nearly 600 reported psychiatric incidents worldwide, most of them in Japan, since the drug was introduced. The incidents, of which 20 per cent were in the US, included self-harming behaviour, delirium and suicide attempts. 25 of them were fatal, with 3 of the deaths being in the US.

The drug’s warning label was changed last year following reports of psychiatric symptoms in patients taking the drug. But the panel is not asking for the warnings to be removed, only that information is added to explain that the symptoms could be caused by the flu itself.

Roche presented the agency with results from its own trials involving more than 150,000 patients that showed no link between Tamiflu and increased risk of psychiatric events.

Roche product director, David Reddy told the AP in an interview on Tuesday that over the last year they had been looking at a range of results from various studies and so far they had found no link between Tamiflu and psychiatric events, He said, “In fact, the data increasingly points to the role of influenza in these events.”

The panel also advised similar changes be made to the label for Relenza (zanamivir, made by GlaxoSmithKline), another flu drug that is less used than Tamiflu. It did not advise labels be changed for amantadine (trade name Symmetrel, approved as an anti-flu drug in 1976) and rimantadine (trade name Flumadine, approved in 1994).

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Written by: Catharine Paddock