FDA Expands Tamiflu's Use to Treat Children Younger Than 1 Year

The Food and Drug Administration today expanded the approved use of Tamiflu (oseltamivir) to treat children as young as 2 weeks old who have shown symptoms of flu for no longer than two days.

The drug is not approved to prevent flu infection in this population. In addition, the safety and efficacy of Tamiflu to treat flu infection has not been established in children younger than 2 weeks old.

Tamiflu was approved in 1999 to treat adults infected with flu who have shown symptoms for no longer than two days. It has since been approved to treat flu in children ages 1 year and older who have shown symptoms of flu for no longer than two days, and to prevent flu in adults and children ages 1 year and older.

Although there is a fixed dosing regimen for patients 1 year and older according to weight categories, the dosing for children younger than 1 year must be calculated for each patient based on their exact weight. These children should receive 3 milligrams per kilogram twice daily for five days. These smaller doses will require a different dispenser than what is currently co-packaged with Tamiflu.

Pharmacists must provide the proper dispenser when filling a prescription so parents can measure and administer the correct dose to their children, says Edward Cox, MD, MPH, director of the Office of Antimicrobial Products in the FDAs Center for Drug Evaluation and Research. Parents and pediatricians must make sure children receive only the amount of Tamiflu appropriate for their weight.

Tamiflu is the only product approved to treat flu infection in children younger than 1 year old, providing an important treatment option for a vulnerable population. According to the Centers for Disease Control and Prevention (CDC), children younger than 2 years are at higher risk for developing complications from the flu, with the highest rates of hospitalization in those less than 6 months of age.

The FDA expanded the approved use of Tamiflu in children younger than 1 year based on extrapolation of data from previous study results in adults and older children, and additional supporting safety and pharmacokinetic studies sponsored by both the National Institutes of Health and Roche Group, Tamiflus manufacturer.

Pediatric legislation permits efficacy to be extrapolated from previous study results in adults and older children if the illness being studied and the effects of the drug are sufficiently similar in adult and pediatric patients. Data on how the drug is metabolized in the body (pharmacokinetic data) indicated a dose of 3 mg/kg twice daily provided concentrations of Tamiflu similar to those observed in older children and adults, and is expected to provide similar efficacy in this very young age group.

Almost all of the 135 pediatric patients enrolled in the two safety studies had confirmed flu. Results from these studies showed the safety profile in children younger than 1 year was consistent with the established safety profile of adults and older children. The most common side effects reported with Tamiflu use in this age group include vomiting and diarrhea. Although not seen in the new studies, rare cases of severe rash, skin reactions, hallucinations, delirium, and abnormal behavior have been reported.

The FDA monitors drugs for side effects and believes reporting side effects is important. Health care professionals and patients should report any side effects associated with Tamiflus use to FDAs MedWatch program.

Tamiflu is not a substitute for early, annual flu vaccination, as recommended by the CDCs Advisory Committee on Immunization Practices. CDC recommends all persons aged 6 months and older receive an annual flu vaccine.

Tamiflu is distributed in the United States by South San Francisco-based Genentech, a member of the Roche Group.