FDA urges warning for Tamiflu and Relenza

The Food and Drug Administration has advised Roche Holding AG and GlaxoSmithKline Plc to put warnings on the two most common drugs used to treat the flu, Tamiflu and Relenza. The drugs in question may cause psychiatric side effects.

A report was submitted by the staff of the FDA to review use of the antiviral medications Tamiflu, made by Roche Holding, and Relenza, from GlaxoSmithKline. The report states deaths and side effects including delirium, hallucinations or psychosis, particularly among children in Japan who are took these drugs.

There is however no clarity as to whether the deaths and behavior were caused by the drugs, the virus, or a blend of both. The agency staff wrote in the report posted on its Web site "Although there is still uncertainty about the cause of the reported abnormal behavior in patients, it is prudent to add information to the labeling. We will continue to monitor these products."

Tamiflu is Roche's ninth-biggest selling drug. It generated $257 million in the third quarter even though sales were down 62 percent from a year earlier. In Japan, the drug is marketed by Chugai Pharmaceutical Co., which is more than 50% owned by Roche. Relenza, on the other hand generated 28 million pounds ($58 million) for Glaxo in the third quarter, down 7 percent.

Basel, Switzerland based Roche claims that the flu and not the drug, causes the reported side effects. Terry Hurley, a company spokesperson said, "If the F.D.A. concludes that it is valuable to place additional details on the label with regard to specific adverse event reports, then Roche is open to that consideration. We would also remind patients that reports of neuropsychiatric events are infrequent and not definitely triggered by using Tamiflu."

The F.D.A. staff members said in the Nov. 9 memorandum that the label on the drug should alert doctors and family members that psychotic side effects may happen quickly and can be fatal.