Is antiviral drug Tamiflu safe for young children?

Tis the 2012 flu season. On December 21, the Food And Drug Administration (FDA) expanded the use of the antiviral drug Tamiflu (oseltamivir) to treat children as young as two weeks of age who have shown symptoms of influenza (flu) for no longer than two days. In 1999, Tamiflu was approved to treat adults infected with flu who exhibited symptoms for no longer than two days. It has since been approved to treat flu in children ages one year and older who have shown symptoms of flu for no longer than two days, and to prevent flu in adults and children ages one year and older. However, the drug is not approved to prevent flu infection in children younger than one year of age.

In addition, the FDA notes that the safety and efficacy of Tamiflu to treat flu infection has not been established in children younger than two weeks of age.

The FDA expanded the approved use of Tamiflu in children younger than one 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, Tamiflu’s manufacturer. Two safety studies that comprised 135 pediatric with confirmed flu were conducted. 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 were 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.

According to the American Academy of Pediatrics (AAP), young children are at increased risk of flu-related complications. On November 2, 2011, the academy issued an advisory entitled: “Prevention and Control of Influenza: Special Considerations for Newborns and Very Young Infants.” The AAP noted that children younger than five years of age, especially very young infants (those younger than 12 weeks of age), are at increased risk of influenza-related complications and, therefore, should be observed carefully for any signs and symptoms of influenza. When very young infants younger than 12 weeks of age present with fever and irritability, cough, tachypnea (rapid breathing), or vomiting, their condition warrants comprehensive medical evaluation.

In general, the AAP recommends that treatment should be considered:

• For any child younger than two years of age with confirmed or suspected influenza virus infection.
• When a decrease in duration of clinical symptoms is felt to be warranted by the physician. Early treatment provides the most benefit, particularly if initiated within 48 hours of illness onset.
• Although influenza testing can be a particularly important tool to prevent the spread of illness, the use of antiviral treatment should not be delayed, whether or not a physician decides to test for influenza.

The AAP notes that newborns and very young infants warrant special consideration. Earlier treatment provides more optimal clinical responses; however, treatment after 48 hours of symptoms in the child with moderate-to-severe disease or with progressive disease might still provide some benefit.

Details for term and preterm infants younger than 12 months of age: