Flu Home > Understanding How Flumadine Works and Pediatric/Off-Label Indications
It is thought that Flumadine works by inhibiting the uncoating of the flu virus, an important step in the replication (the "reproduction") of the virus. Specifically, Flumadine inhibits the activity of the influenza virus M2 protein, which forms a channel in the virus membrane. As a result, the virus cannot replicate (make copies of itself) after it enters a human cell.
Flumadine is effective only for some influenza A viruses and is not effective against influenza B viruses. Since the "bird flu" or "avian flu" virus (H5N1) is a type of influenza A, it is possible that Flumadine may work for some strains of this virus. However, many strains of H5N1 influenza are resistant to Flumadine.
For any given year, the predominant flu strain may or may not be susceptible to Flumadine. If the predominant flu strain is not susceptible to Flumadine, this medication should not be used to prevent or treat the flu.
Flumadine is approved to prevent the flu in children as young as one year of age. It is approved for flu treatment in adolescents age 16 and older. Because Flumadine is available commercially only in tablets, your pharmacist may need to make a liquid version out of the tablets for young children.
On occasion, your healthcare provider may recommend Flumadine for treating something other than the conditions discussed in this article. This is called an "off-label" use. At this time, there are no universally accepted off-label Flumadine uses.