Tamiflu controversy in Canada

Health Canada has asked Swiss drug maker Hoffman-La Roche to update the safety information on its influenza drug, Tamiflu.

The request comes after international reports of rare cases of hallucinations and abnormal behaviour in people who have taken it.

The department warned Canadians on Wednesday of the reports of adverse events, the majority of which involved children and teenagers in Japan. Japan is the highest per capita user of Tamiflu, which until recently has posted weak sales in North America.

Two weeks ago, the U.S. Food and Drug administration issued a similar warning to the American public.

The advisory said that as of Nov 11, there had been 84 reports of adverse events in Canadian Tamiflu users, including 10 deaths. However, the department said it has not been proven that the drug caused the deaths, which mostly occurred in elderly patients, who run the highest risk of death from bouts of flu.

'There have been no Canadian reports of abnormal behaviour or deaths involving children,' Health Canada said.

In related news, Roche is aiming to quell rumours of Tamiflu resistance with the announcement that resistance rates remain low in treated patients.

The company said there have been no new cases of resistance seen in patients infected with the bird flu H5N1 virus since March 2005 and scientific data does not substantiate increased resistance to Tamiflu (oseltamivir).

The company said that over the past few months, there has been erroneous speculation that resistance to Tamiflu is increasing but that both Roche and independent groups have been 'monitoring' the situation and there is no scientific evidence to suggest this is happening.