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.