Flu Medications

Although there is currently no medical treatment that will cure the flu, there are four medications that may shorten the course of the virus and decrease the severity of the symptoms if you begin taking them within the first 2 days of the onset of the symptoms.

All of these medications reduce the ability of the influenza virus to reproduce by attacking enzymes necessary for viral replication.

Two older drugs are well known—amantadine (Symmetrel®) and rimantadine (Flumadine®). Both are mildly effective in retarding epidemic Type A influenza virus. Tablets taken twice daily for 5 days may reduce the symptoms and the course of the flu by somewhere between 1 and 2 days. Both drugs are readily available, covered by all forms of insurance and available for use in children.

Two new drugs became available in 1999 -- oseltamivir (Tamiflu®) and zanamivir (Relenza®). Tamiflu is a tablet, also taken twice daily for 5 days, while Relenza is a powder inhaled twice daily for 5 days. Both drugs block viral replication at a different metabolic site than used by the older medications. As a result, they work not only against epidemic Type A influenza, but also for more sporadic Type B influenza viral infections. Again, both drugs may reduce symptoms and retard the course of the influenza virus.

No scientific evidence is currently available to show whether the new drugs are actually better than the old drugs. Furthermore, because the duration of the virus may be only 1 day, it is unclear that the cost of even the older, less expensive, medications is justified. For these reasons, many insurance companies, especially HMOs, are refusing to pay for the newer medications until the further scientific studies required are completed.

While side effects of anti-influenza medications are low, they are not zero. They may include primarily gastrointestinal upset—particularly nausea—and also may include dry mouth and mild blurry vision or dizziness or insomnia. People with respiratory diseases such as asthma may experience difficulty breathing after inhaling zanamivir. Amantadine has been associated with an increase in seizures among patients with a history of seizure disorders.

Neither of the new drugs is yet available for use in children.

The best way to avoid the flu is clearly to take an annual influenza vaccination. However, the vaccine is not perfect, and its effectiveness can vary from year to year, primarily due to the ability of influenza virus to mutate rapidly.