Concerns that the influenza drug Tamiflu -- seen as effective
against a possible pandemic triggered by bird flu -- may induce
fatal side effects are growing in Japan after two people who took
it fell to their deaths last month.
The deaths, the latest cases of abnormal behavior by those who
took Tamiflu, prompted the Health Ministry to issue a warning
last week that influenza patients could show psychiatric problems,
although it has denied the drug was responsible for them.
But the move was too little too late, said a group whose members
say they are victims of Tamiflu side effects, which came to light
in Japan in 2005 after 12 children died and 32 experienced abnormal
behavior after taking the drug.
"Had they issued a warning earlier, then the number of deaths
could have been halved," said Haruhiko Nokiba, whose 17-year-old
son walked onto an expressway shortly after taking Tamiflu and
was hit and killed by a truck in 2004.
The incident was seen as a suicide, but Nokiba, who heads the
victims and families group, said his son had no reason to kill
himself and circumstances showed that it was a result of abnormal
behavior.
"He ran out into the snow barefoot in his pajamas, climbed
over a 3-meter fence to cross train tracks and then ran into a
truck," Nokiba told Reuters in an interview this week.
According to the Health Ministry, 54 people have died so far
after taking Tamiflu, and in February, a 14-year-old girl and
a boy fell to their deaths from their apartment homes in separate
incidents after taking the drug. Neither had left a suicide note.
NO LINK PROVEN
Swiss drug maker Roche Holding AG, which produces Tamiflu, also
known generically as oseltamivir, has denied a link between the
medication and the deaths, adding that influenza itself could
cause psychiatric problems.
"These events are extremely rare in relation to the number
of patients treated," Roche spokeswoman Martina Rupp said
last week.
"It's very important to state that none of these events
were linked to Tamiflu."
Tamiflu has been used to treat 50 million people since it was
approved in 1999, and in 2005, there were only 103 reports of
neuropsychiatric problems, Rupp added.
Countries around the world are stockpiling the antiviral drug
in case of a human influenza pandemic that experts fear could
be sparked by the H5N1 bird flu virus.
Chugai Pharmaceutical Co. Ltd., which sells the drug in Japan,
added a reference to abnormal behavior as a possible side effect
inside Tamiflu's package in 2004, but victims' groups want a stronger
warning.
In November, the U.S. Food and Drug Administration decided to
require Roche to put a caution on Tamiflu labels urging close
monitoring for abnormal behavior, such as delirium, although it
said it was unknown if the drug contributed to the psychiatric
problems.
A survey of some 2,800 children conducted by a Health Ministry
team last year found that there was no evidence of a relationship
between Tamiflu and abnormal behavior.
Of those who took the drug, 11.9 percent showed such behavior,
while 10.6 percent of patients who did not use the medication
also exhibited abnormal behavior, the poll showed.
But Rokuro Hama, a medical doctor who heads a watchdog group
on the side effects of drugs, said the ratio of those showing
abnormal behavior is four times higher among those who took Tamiflu
if limited to the period immediately after taking the drug.
The ministry is carrying out a more thorough survey aiming to
poll 10,000 influenza patients and come up with the results later
in the year, a ministry official said.
(Additional reporting by Sam Cage in Zurich)
