This week, an FDA advisory panel will review a recommendation to put a warning on flu drugs Tamiflu and Relenza that says there have been “psychiatric events observed in some patients.” The companies who make the drugs have both responded that they’ve found no causal link between their drugs and “psychiatric events.”
Even the FDA has mixed feelings about it, which it may resolve this week.
The FDA staff said the evidence is “conflicting” as to whether the events are medication-related, a manifestation of disease or a combination of the two.
Tamiflu has been more widely used in Japan than in the United States, and there is some evidence that the Japanese are more vigilant about reporting side effects, the FDA has said.
FDA staff based its recommendations on a review of nearly 600 cases of neuropsychiatric events reported by patients on Tamiflu and 115 cases of such events by patients taking Relenza.
Tamiflu already has a warning label that says patients should be closely monitored “for abnormal behavior such as delirium or self-injury,” which the FDA placed on it after a report two years ago that 12 Japanese children who were taking Tamiflu died. Relenza is currently free from any psychiatric warning.
The new Tamiflu warning would state: “”In some cases, these behaviors resulted in serious injuries, including death, in adult and pediatric patients.”
For Relenza, the proposed warning would caution that “reports of hallucinations, delirium and abnormal behavior” have been observed in some patients.