Flu and Influenza Treatment with Anti Viral Drugs

Four antiviral drugs (amantadine, rimantadine, zanamavir and oseltamivir) have been approved by the U.S. Food and Drug Administration (FDA) for treatment of influenza. These need to be taken within 2 days after becoming sick. If taken at the appropriate time, these drugs can reduce flu symptoms and may shorten the time you are sick by 1 or 2 days and also make you less contagious. All of these drugs must be prescribed by a doctor and taken for 3-5 consecutive days (5 days for oseltamivir and zanamivir). When used for prevention, they are about 70% to 90% effective in preventing illness in healthy adults.

All of the antiviral drugs may be effective for influenza A viruses. However, only oseltamivir and zanamivir are effective for influenza B viruses. These drugs, called neuraminidase inhibitors, block the normal function of the viral neuraminidase. Both drugs are available only by prescription. One of the drugs, zanamivir (Relenza®, Glaxo Wellcome Inc.) is inhaled as a powder twice a day for 5 days. A special device called a disk haler is supplied with the medication. The other drug, oseltamivir phosphate (Tamiflu TM, Roche Pharmaceuticals), is a tablet that is taken by mouth twice a day for 5 days. According to the WHO, Tamiflu (Oseltamavir) might be useful for influenza prevention and treatment in the possibility of an H5N1 Pandemic. Oseltamivir, also called Tamiflu are used for the bird flu and virus H5N1 strain. The World Health Organization (WHO) has mentioned Tamiflu as the drug for tackling bird flu if ever a human pandemic breaks out.

Use of Antiviral Drugs
Antiviral drugs for treating influenza are most often used to help control influenza outbreaks in institutions, like nursing homes or in hospital wards, where people at high risk for complications from influenza are in close contact with each other. Antivirals also have been used on cruise ships or similar settings to help control influenza outbreaks.

In the event of an outbreak, public health practice is to combine the use of influenza vaccine and antivirals. For example, nursing home residents and staff are given vaccine during an outbreak and also are given antivirals to prevent influenza until the vaccine takes effect (about 2 weeks). This practice continues as long as influenza is occurring in that setting.

Influenza antivirals are prescribed in case of outbreaks and the treatment must begin within 2 days of the onset of symptoms for the drugs to be effective. Although all antivirals lessen symptoms and shorten the duration of illness, only one (oseltamivir) has been shown in a study to reduce lower respiratory tract complications requiring antibiotics. They do not cure influenza outright.

When considering the use of antivirals it is important to remember that most healthy people recover from influenza without complications.

Who Should Get Antiviral Drugs
People who are at high risk of serious complications from influenza may benefit most from antiviral medications. This includes: people 65 years of age and older, children 12-23 months of age, people with chronic medical conditions (for example, heart or lung disease, diabetes), and pregnant women. (Note that none of the antivirals are approved for use in children less than 1 year of age.). In any case you must consult your doctor on the choice and use of antiviral drugs, even though CDC has provided guidelines for health-care professionals on the use of antiviral drugs