FDA: Tamiflu May Cause "Bizarre" Behavior in Children

Officials with the U.S. Food and Drug Administration are advising physicians and parents of children being treated with the anti-flu drug Tamiflu to watch their children carefully for signs of bizarre or unusual behavior. Over 100 cases have been documented overseas where children taking Tamiflu experienced disturbances in normal behavior patterns. Of those cases, three children have died from falls. Officials don’t’ know whether the changes in behavior have been linked to the medication, the flu virus, or a combination of the two.

Most of the cases of bizarre behavior have been documented in Japan, where the number of new Tamiflu prescriptions is about 10 times the number in the United States. The new 103 cases occurred over the course of 10 months between August 2005 and July 2006. The number of cases indicates a sharp increase in the number of cases logged over the five previous years since Tamiflu was approved in 1999.

Tamiflu is produced by the Swiss pharmaceutical company Roche Holding AG, which has cited studies showing that the death incidence of flu patients taking Tamiflu was far lower than those patients who did not. Tamiflu is one of the few drugs that health officials believe may be effective in treating bird flu, which is still looming on the horizon for causing a pandemic should the virus mutate into a form easily passed from human to human. Tamiflu doesn’t prevent the flu, but it can reduce the length and severity of symptoms.

The FDA’s pediatric advisory committee has recommended that the FDA monitor the drug’s safety, even though the panel rejected theories that linked Tamiflu to the deaths of 12 children in Japan since 2000 and voted against changing the drug’s labels to suggest any concerns. However, the Japanese Tamiflu label now warns people to be on the lookout for disturbances in consciousness, abnormal behavior, hallucination, delusion, delirium, and convulsion, recommending that patients be closely monitored and the drug stopped if any bizarre behavior is observed.

Even though severe cases of the flu itself can bring about those types of behavior, the FDA has not ruled out Tamiflu as the cause because of the large number and nature of the cases. For that reason, federal officials have suggested updating Tamiflu’s label to bring it more in line with the Japanese one. However, FDA staff acknowledged that stopping treatment with the drug could actually be harmful to flu patients if the virus is the actual cause of the delirium, hallucinations, and other behavior. For that reason the proposed U.S. version would recommend that the medication be stopped only on the advice of a physician.

Federal officials say that the proposed changes are prudent, since the usage of Tamiflu could soon rise to the same levels of usage in Japan. The current U.S. label mentions only that "seizure and confusion" may be seen in some patients.