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Saturday, May 30, 2009
Little alternative to risky flu drugs
Teens under treatment have shown abnormal behavior but no link has been proved
By MARIKO KATO
Many may wonder at the use of Tamiflu to treat young victims of the H1N1 flu, given reports in recent years of teen deaths linked to the antiviral drug. But experts say prescribing Tamiflu is inevitable because there are only limited alternatives for combating the latest virus.
"It is commonly understood among pediatricians in this country that abnormal behavior such as hallucinating and jumping off buildings are symptoms of influenza, not the drugs," said Norio Sugaya, an infectious diseases expert and head of the pediatrics department at Keiyu Hospital in Kanagawa Prefecture.
Many cases of self-destructive behavior among users of Tamiflu, imported by Chugai Pharmaceutical Co. from Swiss drug giant Roche, have been reported, particularly among teens.
Following a succession of fatal cases where teenagers leaped off buildings immediately after taking the medicine, the Health, Labor and Welfare Ministry banned its prescription in principle to those aged between 10 and 19 in 2007.
However, whether Tamiflu leads to abnormal behavior has not been confirmed, and the ministry this year published a report saying only "the causal relations cannot be denied."
With the onset of the swine flu epidemic, the government is quietly encouraging the use of Relenza, another flu treatment available in Japan for young patients, made by British firm GlaxoSmithKline. In reality, however, both Tamiflu, which it has been publicly stockpiling, and Relenza are being administered.
For example, at the school in Osaka where 61 students were infected with the new virus earlier this month, the Infectious Disease Surveillance Center surveyed 18 of those who had been hospitalized. Among them, nine had been prescribed Tamiflu and five Relenza, while three had taken both. The lone remaining patient was administered either.
Sugaya said that prescribing Tamiflu to young people is unavoidable, because the majority of the H1N1 patients have been high school students.
"If parents are very worried about its side effects, we administer Relenza. But Relenza users have shown abnormal behavior, too, as well as those who have not taken either," he said.
According to Katsu Saionji, an infection control expert and associate professor at the National Defense Medical College, both Tamiflu and Relenza are generally only administered to swine flu patients who are hospitalized or kept at a hotel, not to outpatients.
"We're keeping a close watch on those on the drugs for abnormal behavior," he said, adding that the effectiveness of the two medicines in fighting the virus is the same.
One of the reasons why Relenza has not been as commonly used as Tamiflu in the past is because it is in powder form and taken by inhalation, Saionji said.
"This makes it difficult for young children, and it cannot be prescribed to those with asthma," he said. He added that Relenza comes with sizable inhalation equipment, which makes it cumbersome to use and difficult to stock up on.
Compared with Japan, Tamiflu-linked deaths have not been as widely reported abroad. According to Sugaya, this is because influenza itself is not as frequently detected in other countries. About 90 percent of the world's stock of rapid test kits used to detect influenza are used in Japan, where they are covered by insurance, resulting in more diagnoses of influenza, and thus more reports of deaths that may be connected with Tamiflu, he said.
"Overseas, even if there are deaths among ill teenagers, they may put them down to drugs or bullying. After all, children that age have many problems," he added.
Researchers at the Infectious Disease Surveillance Center have begun to prepare vaccines for the new flu, but it is believed that it will take at least six months before they become available. In addition, the government has not decided how much vaccine to produce because it also needs to prepare vaccines for seasonal flu.
According to the health ministry, the government has enough Tamiflu for 34 million people and Relenza for 4.7 million. This should be enough to last until the winter, Sugaya said.
"Swine flu is calming down now that it's summer, and we will have enough (Tamiflu and Relenza) for the next wave, which may come in the autumn and winter. By then, I'm sure other pharmaceutical companies will have made other drugs," he said.
While Tamiflu and Relenza help limit the spread of the virus within the body, Saionji warns that they do not cure the infection unconditionally.
"You need to take them within 48 hours after the symptoms appear, otherwise they're not effective. Even then, they serve only to bring down the fever more quickly," he said.
Sugaya agrees that neither drug provides the foolproof answer to fight the new virus.
"Humans aren't God, so we can't make medicines that are absolutely perfect or safe," he said.