A Bosnian pharmacist displays Swiss drug maker Roche’s Tamiflu bird flu anti-viral tablets at a pharmacy in the capital Sarajevo February 18, 2006. (Danilo Krstanovic/Reuters)

WASHINGTON (Reuters) -
Two rival flu drugs, Tamiflu and
Relenza, work equally well to fight the symptoms of influenza
in children, Japanese researchers reported on Thursday.

Doctors can feel free to choose either drug in treating
children and may prefer Relenza, made by GlaxoSmithKline and
known generically as zanamivir, for youths aged 10 to 19, they
said.

They said their study was the first head-to-head comparison
in children of the two drugs, in a class known as neuraminidase
inhibitors.

The issue is important in Japan, where the drugs are
heavily used and where doctors are still trying to determine if
Roche's Tamiflu, known generically as oseltamivir, may have
been linked with some suicides.

Dr. Norio Sugaya of Keiyu Hospital in Yokohama and
colleagues studied nearly 350 children treated with either one
of the drugs for influenza.

“More than 70 percent of the total amount of oseltamivir
prescribed throughout the world each year is used in Japan,”
they wrote in the journal Clinical Infectious Diseases.

“Most patients in Japan with an influenza-like illness are
now tested with rapid diagnostic tests; when results are
positive, they are treated with a neuraminidase inhibitor,
usually oseltamivir,” they said.

But because of reports of psychiatric reactions, the
Health, Labor, and Welfare Ministry of Japan suspended use of
Tamiflu for patients aged 10 to 19.

“Accordingly, zanamivir will be prescribed widely for
teenaged patients with influenza,” the researchers wrote.

Both drugs can reduce the severity of illness if given soon
enough and can cut a few days off how long a patient is ill.

Sugaya's team found almost no differences between the drugs
when used to treat flu in children. Both drugs cut about two
days off the time the children had fever, they found.

“Oseltamivir and zanamivir were equally effective in
reducing the febrile period of children with influenza A
(H1N1), influenza A (H3N2), and influenza B virus infection,”
they wrote.

Both drugs worked better against H3N2 flu than they did
against either H1N1 or influenza B viruses, the researchers
added.

Such comparisons may also be useful in planning for a
pandemic of influenza. Many experts predict a pandemic is
coming, with the current chief suspect the H5N1 avian influenza
strain that has become entrenched in birds across much of Asia,
Europe, the Middle East and Africa.

It rarely infects people now but has killed 243 out of 385
infected. Quick use of Tamiflu has been credited with saving
some lives.

(Reporting by Maggie Fox; Editing by Will Dunham and Bill
Trott)