Tamiflu and Relenza, drugs used to treat the flu, could soon bear new warnings about psychiatric side effects if the recommendations of Food & Drug Administration (FDA) staffers are followed. According to documents released today, FDA staffers have recommended the new warnings because of reports linking Tamiflu and Relenza to psychiatric events, including hallucinations, delirium and other abnormal behavior. An FDA advisory panel is set to review Tamiflu and Relenza safety at a meeting next week.
Documents prepared for next week’s FDA advisory panel meeting where posted on the agency’s website today. In those documents, FDA staff have recommended new psychiatric warnings for Tamiflu and Relenza. The recommendation says that the Relenza label should be changed to warn of “reports of hallucinations, delirium and abnormal behavior” observed in some patients taking the drug. Though Tamiflu already bears a psychiatric event warning, FDA staffers say it should be strengthened to say: “In some cases, these behaviors resulted in serious injury, including death, in adults and pediatric patients.” The recommendations included in the online documents will be presented to an FDA advisory panel on Tuesday, November 27.
The FDA staff recommendations where based on a review of nearly 600 psychiatric event reports in Tamiflu patients, and another 115 reports among people taking Relenza. The online documents said that there have been reports of 596 neuropsychiatric events, including 16 neuropsychiatric-related deaths, among children and adults taking Tamiflu. Among those reports, 75% came from Japan. In total, the FDA said, there were 25 deaths from all causes reported among Tamiflu users on a world-wide basis in patients younger than 21. Japan was also the origin of 81 of the Relenza reports, but no deaths where associated with that drug. Of the 50 million people treated with Tamiflu since its approval in 1999, the majority of users – 35 million – have been in Japan.
In 2005, Japan issued a Tamiflu warning against prescribing the drug to people between the ages of 10 and 19. The Japanese Tamiflu warning came after 100 people, mostly young, experienced a psychiatric event after taking Tamiflu. The FDA convened an advisory panel to discuss the matter that year, and the FDA and the panel concluded the events likely weren’t related to Tamiflu. However, the panel recommended the agency keep monitoring the drug. Earlier this year, Japan also announced that it would be reviewing the safety of Relenza and another anti-flu drug, Amantadine, after those drugs were also linked to psychiatric events.
Those reports also led the FDA to monitor Amantadine, but so far staffers are not recommending any label changes. Amantadine already has a strong warning regarding seizures and suicide attempts seen in users.