Troubled behaviors and sudden deaths have agency looking into Tamiflu; Relenza also under scrutiny.
TUESDAY, Nov. 27 (HealthDay News) -- A U.S. Food and Drug Administration panel is meeting Tuesday to debate stronger warning labeling for the prescription flu drug Tamiflu (oseltamivir), linked recently to anecdotal reports of bizarre behaviors and deaths among children.
The FDA's Pediatric Advisory Committee will begin considering label changes to Tamiflu and another flu drug, Relenza (zanamivir), when used in children.
A safety review released Friday by the FDA's Division of Antiviral Products does urge stronger label warnings for the medications, including stricter monitoring of children taking these drugs.
One expert is concerned that the public may overreact, however.
"I am not a fan of replacing fear of a disease with fear of the treatment for the disease," said Dr. Marc Siegel, a clinical associate professor of medicine at New York University School of Medicine in New York City. "You don't need to go from one panic to another," he added.
Tamiflu is overused, however, Siegel said. "It's supposed to be used in a very narrow window, and I am not surprised that there have been psychiatric side effects related to this drug," he said. "Maybe the new warning will lead to less overuse," he said.
According to the FDA safety review, there have been 596 reported cases of psychiatric behavior associated with Tamiflu use. Most of these cases happened among patients 21 or younger. The majority (75 percent) occurred in Japan.
Fifty-nine of the cases were classified as delirium with impulsive behavior and self-injury. Delirium, delusions, hallucinations or psychosis accounted for another 225 cases. In total, five children died "as a result of falls from windows or balconies or running into traffic," the safety review found, and three adults committed suicide. So far, there haven't been any such cases reported in the United States, according to the FDA.
The FDA began reviewing Tamiflu in 2005, and, since November 2006, the drug's label has had a warning focused on self-injury and delirium. The label also advises that patients be monitored during treatment. In March of this year, the Japanese Ministry of Health, Labor, and Welfare limited Tamiflu use in patients 10 to 19 years of age.
In their safety review, experts at the FDA advised the committee to amend the label warning to note that there were deaths in Japan related to Tamiflu and to strengthen monitoring for patients taking the drug.
However, "A restriction on the use of oseltamivir in the U.S. does not seem warranted at this time based on the post-marketing data and the still unanswered question about whether these events are due to oseltamivir, influenza/fever, or a combination of the two," the agency safety review said.
The maker of Tamiflu, Hoffmann-La Roche Inc., of Nutley, N.J., noted that Tamiflu is used some six times more in Japan than in the United States. Moreover, whether the bizarre behavior observed is a result of the drug or the flu itself remains unclear, the company said.
The company sees no need for a label change. "Thus, the information on neuropsychiatric events currently within the Precautions section of the Tamiflu [label] continues to be an accurate assessment of all available updated and expanded data," it said in a report to the FDA.
Siegel believe a new warning is appropriate. "The idea that there have been 596 neuropsychiatric events is a reason for the FDA to put a strong warning on the label," he said.
Millions of people have taken the drug, so the odds that any one patient would have these reactions are very low, Siegel said. "People in high-risk groups achieve more benefit from the drug [against the flu] than they accrue risk for neuropsychiatric events," he said.
Tamiflu is approved both as a preventive and a treatment for flu for adults and children one year and older.
The FDA is also asking the committee to add a similar warning to another flu drug, Relenza (zanamivir). There have been 115 reported cases of "delirium with impulsive behavior and self-injury in which the patient expressed 'fear' and attempted to flee or expressed a desire to 'jump,' " the agency said. There were no deaths associated with Relenza, and, as with Tamiflu, 70 percent of the cases occurred in Japan.
GlaxoSmithKline, the British maker of Relenza, doesn't believe the label needs changing. "The review and analysis of all the information available in this safety summary of neuropsychiatric events does not implicate or indicate a significant causal role of zanamivir. Therefore, no revisions are warranted for the U.S. Prescribing Information and the FDA-approved Patient Labeling for Relenza," the company told the FDA.
Relenza is approved as both a flu preventive and a treatment in adults and children five years old and older.
In addition, The FDA reviewed side effects associated with two other flu drugs Symmetrel (amantadine) and Flumadine (rimantadine). They are not recommending any label changes for these drugs.
For more on flu, visit the U.S. Centers for Disease Control and Prevention .
SOURCES: Marc Siegel, M.D., clinical associate professor, medicine, New York University School of Medicine, New York City; Pediatric Safety Update for Tamiflu, Division of Antiviral Products, U.S. Food and Drug Administration; statements, GlaxoSmithKline and Hoffmann-La Roche Inc.
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