Teenage suicides and Tamiflu - is there a link?

Roche the maker of the anti-flu drug Tamiflu has reported to authorities in Japan the possible suicides of two teenage boys although the company says there was no clear evidence that the drug had contributed to their deaths.

At present Tamiflu is considered one of the best defences against bird flu in humans and is in great demand as fears grow about the spread of the deadly virus.

Roche says the cases of the two boys have been listed as examples of so-called adverse events in the packaging supplied with the antiviral pill.

The local Japanese media has reported that health authorities were investigating the deaths, following concerns over the side effects of the medicine.

David Reddy, Roche's head of pandemic sales of Tamiflu, says that one teenager died after falling from the window of an apartment block in February while another was killed after walking in front of a truck in February 2004.

Apparently in the case of the boy who fell, there was insufficient evidence to tell whether he had intended to kill himself, says Reddy as the boy had been taking another drug, known to affect the central nervous system, before switching to Tamiflu.

Reddy says that one of the issues faced in examining the background for any incident is determining the potential contribution of a drug or the contribution of the underlying illness.

He says Roche does not see an imbalance in these types of neuro-psychiatric events for Tamiflu versus the background associated with influenza, and they have not seen an increased rate of abnormal behaviour.

According to the Japanese Health Ministry it had instructed the drug maker last year to alert doctors to possible side effects such as abnormal behaviour.

Roche said it continued to monitor the safety of the drug, adding that over 30 million people worldwide had used it.

Analysts are playing down the concerns, and in general hold the view that any kind of treatment could lead to mood disorders and therefore be linked to suicidal thoughts but is often very difficult to establish.

The Health Ministry in Japan had already ordered Chugai and Roche to include in the literature accompanying the drug, a list of psychological and neurological disorders that could arise as side effects.

A ministry official has said the instruction was based on reports of side effects received previously.

The drug company Chugai which is half-owned by Roche, has added to the literature on the drug the possible side effects, including impaired consciousness, abnormal behaviour and hallucinations.

Shinichi Watanabe, deputy director of the health ministry's safety division, said the ministry has no plans to put restrictions on the use of the drug or to issue additional warnings, but the link between the abnormal behaviour and the drug could not be ruled out, while at the same time the drug could not be singled out as the sole cause of the behaviour.

Chugai launched Tamiflu in Japan in 2001.

During the last flu season it shipped enough doses to treat more than 10 million people.