Swiss pharmaceutical company Roche has played down Japanese fears that its anti-flu medicine, Tamiflu, may trigger mental health problems in those using it.This content was published on March 22, 2007 - 11:50
The firm said there was no proven link between the drug and a number of reported cases of severe psychiatric symptoms.
On Wednesday, the Japanese heath authorities said they had told importers of Tamiflu to warn doctors not to prescribe it to those aged ten to 19, after two new reports of young people injuring themselves by jumping from buildings after taking the drug.
Roche said that it did not understand the rationale behind the Japanese government's actions.
"There's no proof that Tamiflu causes suicides," Roche spokeswoman Martina Rupp told swissinfo. "It is allowed all over the world to use Tamiflu from the age of one year onwards."
Roche says new data showed fewer psychiatric symptoms in influenza patients treated with Tamiflu than in patients who hadn't received the drug.
Both Roche and the United States Food and Drug Administration have argued that severe cases of flu may trigger the abnormal behaviour displayed by some patients.
Tamiflu is widely used in Japan to treat influenza.
A senior Roche official, David Reddy, said that of the 45 million people worldwide who have taken the drug since its launch a few years ago, 128 deaths from all causes had been reported - including eight associated with neuro-psychiatric behaviour.
But none had been shown to be caused by Tamiflu, Britain's Financial Times newspaper quoted Reddy as saying.
Japan's warning that Tamiflu should not be given to teenagers sparked a clash of opinions on Thursday, with some saying it came too late and others saying the drug's benefits outweighed possible risks.
"The Health Ministry is again dragging its feet," read a headline in the conservative Sankei newspaper, referring to a scandal over a past failure to stop the import of HIV-infected blood products.
"Why won't they move until people are injured or die?" the Sankei quoted the parent of one teenage victim as asking.
The latest Japanese government figures show 54 people, including 17 under 20s, have committed suicide after taking the drug.
But Roche said new studies from Japan and the US suggested that influenza could itself cause psychiatric symptoms such as hallucinations.
swissinfo with agencies
Tamiflu is based on shikimic acid, which can be derived by fermentation or from the pod of the star anise fruit.
It was invented by Gilead Sciences, California, and licensed to Roche in 1996. Tamiflu is patent protected until 2016.
Known generically as oseltamivir, the drug is seen as the best defence against a human pandemic that could be triggered by bird flu, which has been found in wild birds across Asia and Europe.
Tamiflu fact sheet
Tamiflu is taken orally in 75mg capsules. It was launched in North America in 1999/2000 and in all key European markets by 2002/2003.
Around 42 million patients have been treated with Tamiflu in about 80 countries.
In Japan, 24.5 million patients have taken the drug, including 11.6 million children. Since 2001, there have been 16 deaths of children aged one to 16 (data as of June 5, 2006). According to the FDA, who conducted a thorough review of 12 of these cases, there is no casual relationship with the administration of Tamiflu. At least eight of the children suffered from pre-existing conditions.
Source: Roche November 17, 2006
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