The FDA (Food and Drug Administration) stressed that oseltamivir is not approved as a preventive medication for infants; it has not been approved for the prevention of flu among babies aged less than one year.
Tamiflu's safety and efficacy for the treatment of flu for patients younger than two weeks old has not been established.
The FDA first approved Tamiflu in 1999 for adults whose influenza symptoms started 48 hours ago or less. It was then approved for children aged 1 year or older who also had flu symptoms for no more than 48 hours. It was also approved for preventing flu in both adults and children aged at least 12 months.
Dosing for very young children - those under 12 months of age - must be calculated individually, based on the child's exact weight, unlike older patients for whom there are general weight categories.
Infants from 2 weeks to 12 months should be given 3 milligrams per kilogram of bodyweight twice daily for five days. For these smaller doses, a different dispenser from the current one that is co-packaged with Tamiflu will be required.
Edward Cox, M.D., M.P.H, director of the Office of Antimicrobial Products in the FDA's Center for Drug Evaluation and Research, said:
"Pharmacists must provide the proper dispenser when filling a prescription so parents can measure and administer the correct dose to their children. Parents and pediatricians must make sure children receive only the amount of Tamiflu appropriate for their weight."
Infants - a vulnerable population for influenza complicationsThe majority of people who get flu recover within a week or two. However, some patients develop complications, some of them life-threatening, such as pneumonia.
Vulnerable populations for influenza complications include:
- Seniors - people aged 65+ years
- Patients with chronic medical conditions, such as heart disease, asthma or diabetes
- Patients with weakened immune systems
- Pregnant women
- Newborns, infants and very young children
The CDC (Centers for Disease Control and Prevention) says that children under the age of 2 years have a higher risk of developing flu complications. Infants aged less than 6 months have the highest flu-related hospitalization rates.
When deciding on this new expansion for Tamiflu usage, to include infants less than 1 year of age, the FDA extrapolated data on studies carried out on older children and adults. It also gathered and analyzed safety and pharmacokinetic data from the Roche group (the makers of Tamiflu) and the NIH (National Institutes of Health).
US regulatory law allows for data to be extrapolated from previous clinical trials in older pediatric patients and adults if the disease and the effects of the medication are similar enough in adults and children.
According to pharmacokinetic data (how the medication is metabolized in the body) "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."
Nearly all of the 135 pediatric patients involved in two clinical trials had been diagnosed with influenza. Study results showed that the safety profile among infants was consistent with the established safety profile of older children and adults.
Tamiflu side effects among this young age group included diarrhea and vomiting. Rare cases of delirium, abnormal behavior, hallucinations, skin reactions and severe rash have been reported (they were not observed in the two studies).
The FDA emphasizes that the reporting of side effects is important. Patients, caregivers, parents and health care professionals should report any side effects linked to Tamiflu use to FDA's MedWatch program.
The CDC recommends that all Americans over the age of 6 months should receive an annual influenza vaccine. Tamiflu is NOT a vaccine, it is not a substitute for the flu jab.
Tamiflu is sold in the USA by Genentech Inc. (part of the Roche Group).
Written by Christian Nordqvist