Note: Information provided may change and should not be used as a substitute for individual evaluation by a health care provider, or as the primary means of diagnosing influenza or determining treatment.
The term influenza refers to illness caused by influenza virus. This is commonly called the flu, but many different illnesses cause flu-like symptoms such as fever, chills, aches and pains, cough, and sore throat. Influenza virus infection can cause different illness patterns, ranging from mild common cold symptoms to typical flu. Some people may be at increased risk for bacterial complications of influenza such as pneumonia, ear or sinus infections, or bloodstream infections.
There are a number of drugs approved by the FDA for the treatment and prevention of influenza but they are not a substitute for yearly vaccination. Yearly vaccination is the primary means of preventing and controlling influenza.
Antibiotics are used to treat illnesses caused by bacteria like strep throat, tuberculosis and many types of pneumonia. Antibiotics do not treat viral illnesses like flu, colds, and most sore throats.
Outbreaks of influenza occur every year and typically reach epidemic levels at some part of the season. Usually, uncomplicated influenza gets better with or without antiviral treatment but may cause substantial discomfort and limit activities while it lasts.
Many people with uncomplicated influenza use over-the-counter medicines, get rest, and take plenty of fluids to lessen their symptoms. Antiviral drugs available by prescription can reduce the time it takes for symptoms to improve, and some are also used in selected situations to reduce the chance of illness in people exposed to influenza virus. Prompt medical evaluation is important for early treatment of influenza as the antiviral drugs may provide the most benefit for patients who initiate therapy within 48 hours of symptom onset.
Symptoms of influenza may mimic other infections which require different treatment (such as bacterial pneumonia which should be treated with antibiotics). Therefore, it is important to be evaluated by healthcare provider, especially if symptoms are severe or worsening. Laboratory tests can help detect influenza virus. However, a negative test does not always rule out the possibility of an influenza virus infection, and positive tests do not exclude the possibility of other illnesses or take the place of clinical evaluation.
Complications of influenza can include bacterial infections, viral pneumonia, and cardiac and other organ system abnormalities. People with chronic medical conditions (including obesity), children younger than 5 years old (and especially children less than 2 years old), patients 65 years and older, residents of long-term care facilities, Native Americans and Alaska Natives and pregnant women may be at increased risk for complications. Complications of influenza, and other illnesses that resemble influenza, may require different treatment and, in some cases, urgent medical attention. Antiviral drugs do not eliminate the risk of complications. Some complications can be life-threatening. There have been reports of people with other types of infections that got worse because they were treated only for influenza and not for the other infections.
Influenza viruses can become resistant to specific anti-influenza antiviral drugs, and all of these drugs have side effects. If you experience new symptoms during treatment or your symptoms persist or get worse during treatment, see your health care professional.
If a new strain of influenza virus is transmitted rapidly, it can cause widespread illness known as a pandemic. Depending on the strain of influenza virus, antiviral drugs may not work to the same extent. The government stockpiles antiviral drugs, and develops recommendations about their use as part of pandemic preparations.
Note: Influenza antiviral drugs are not a substitute for vaccine. They are used in addition to vaccine in public health planning for the control of influenza. The antiviral drugs have been approved for treatment of acute uncomplicated influenza and for some preventive uses.
There are four FDA-approved influenza antiviral drugs recommended by CDC for use against recently circulating influenza viruses.
Two older drugs, amantadine (generic) and rimantadine (Flumadine and generic) historically have been approved for treatment and prevention of influenza A virus infection. But many strains of influenza virus, including the 2009 H1N1 influenza virus, are now resistant to these drugs. CDC has not recommended the use of amantadine and rimantadine for recently circulating influenza viruses, although recommendations could change if there were future re-emergence of specific virus strains with susceptibility patterns favoring such use.
Clinical trials evaluate the safety and efficacy of unapproved products or new uses for approved products. Information about open clinical trials can be found at ClinicalTrials.gov.
Information about expanded access regulations, other aspects of drug development and review, and resources about the approval status of drugs and formulations can be found at: