Updated Labeling Changes for Tamiflu and Relenza
FDA Patient Safety News: Show #75, May 2008

Roche Laboratories has updated information on neuropsychiatric events for Tamiflu (oseltamivir phosphate), a drug that's used to treat or prevent influenza in patients 1 year and older.

The revised labeling reminds practitioners that some patients taking Tamiflu for influenza have experienced delirium and abnormal behavior, leading to accidental injury and a small number of deaths. Most of these events occurred in Japan, and the majority were in children, often with abrupt onset and rapid resolution. Similar events have also been reported with Relenza (zanamivir), an inhaled drug used to prevent and treat influenza, and similar labeling changes have been adopted for that drug.

The role of the drugs in contributing to these events is not established. In fact, the labeling points out that influenza itself can be associated with a variety of neurologic and behavioral symptoms, including hallucinations, delirium, and abnormal behavior.

Patients with influenza should be closely monitored for signs of abnormal behavior, and if a patient does experience neuropsychiatric symptoms, the practitioner should evaluate the risks and benefits of continuing Tamiflu treatment.

Additional Information:

FDA MedWatch Safety Alert. Tamiflu (oseltamivir phosphate). March 4, 2008.
http://www.fda.gov/medwatch/safety/2008/safety08.htm#Tamiflu

FDA MedWatch Safety Alert. Relenza (zanamivir). April 1, 2008.
http://www.fda.gov/medwatch/safety/2008/safety08.htm#Relenza