The health ministry has banned in principle the prescription of the influenza drug Tamiflu to people aged 10 to 19 in the wake of a series of cases in which young patients exhibited abnormal and dangerous behavior after taking the drug. This represents a turnabout from the ministry's earlier negative stance about the existence of a causal relationship between the drug and dangerous behavior. Some patients became unruly and fell from buildings, resulting in several deaths. The ministry decision is likely to have an impact on the Japanese medical scene since Japan accounts for 70 percent of Tamiflu use worldwide. In fiscal 2005, more than 8 million Japanese took the drug.

The ministry needs to fully explain its decision as well as clarify when patients should be given the drug. It also should speed up studies to determine if Tamiflu is indeed responsible for the abnormal behavior. These studies should include a close review of the roughly 1,800 reports of side effects since the drug was first sold in 2001 and an epidemiological survey covering many people.

Abnormal behavior following the ingestion of Tamiflu first attracted attention in November 2005 when two high school students died, one dashing onto a highway and the other falling from a condominium. Three middle school students died in falls -- one in July 2006 and two last month. Fifteen Tamiflu-related falls, resulting in four deaths, involving people aged 10 to 19 have taken place since 2004. Since last year seven adults have fallen from buildings or collapsed after ingesting Tamiflu, resulting in two deaths.