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:
- Term infants, three through 11 months of age, can receive oseltamivir treatment for five days using 3 mg/kg/dose, twice daily. When chemoprophylaxis (prevention) is recommended, the regimen for this age group lasts 10 days at 3 mg/kg/dose, once daily.
- Term infants younger than three months of age can receive oseltamivir treatment for five days using 3 mg/kg/dose, twice daily. Chemoprophylaxis for infants younger than 3 months of age is not recommended unless the exposure situation is judged critical (ie a family member is hospitalized or critically ill), because of the lack of data on use of oseltamivir in this age group.
- Current dosing recommendations are not intended for preterm infants, who may have slower clearance of oseltamivir because of immature renal function, and the dose recommended for term infants can lead to variable or very high drug concentrations in this age group.
As in any medical condition, prevention out-trumps treatment. The Centers for Disease Control and Prevention (CDC) recommends that everyone who is at least six months of age should get a flu vaccine this season. It is especially important for some people to get vaccinated. Those people include the following:
People who are at high risk of developing serious complications like pneumonia if they get sick with the flu. This includes: individuals who have certain medical conditions including asthma, diabetes, and chronic lung disease; pregnant women; and people 65 years and older.
People who live with or care for others who are high risk of developing serious complications. This includes household contacts and caregivers of people with certain medical conditions including asthma, diabetes, and chronic lung disease.
The CDC recommends that people get vaccinated against influenza as soon as 2012-2013 flu season vaccine becomes available in their community. Influenza seasons are unpredictable, and can begin as early as October. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against the flu.