These antiviral medicines prevent the
spread of type A
influenza by interfering with the production of the
virus inside the body. They do not treat or protect you against influenza
These antiviral medicines may reduce the
severity of influenza (flu) symptoms and shorten the course of the illness of
influenza A.1 They need to be started within 48 hours
of the first symptoms and continued, usually, for 7 days.
For the past few years, the U.S. Centers
for Disease Control and Prevention (CDC) have advised doctors not to use
amantadine or rimantadine (Flumadine) to treat or
prevent the flu. These medicines have not worked against most types of the flu
virus. Talk to your doctor about the medicine that is best to use for the
current type of flu.
When used to protect people during a flu
outbreak, antiviral medicines usually are used for 7 days but may be continued
for 5 to 7 weeks.
Amantadine and rimantadine can relieve or prevent symptoms of influenza A if taken soon after infection. But these antiviral medicines do
not always treat or prevent the flu.2
When given within 48 hours after symptoms begin, they may reduce
symptoms, shorten the length of influenza A illness by 1 or 2 days, and allow
for a faster return to usual activities.
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
Call 911 or other emergency services right away if you have:
Call your doctor right away if you have:
Common side effects of these medicines include:
See Drug Reference for a full list of side effects. (Drug
Reference is not available in all systems.)
Amantadine and rimantadine are
effective only against some type A influenza viruses.
usually should not be taken at the same time as antihistamines or other
medicines that stimulate the central nervous system. These may increase the
risk of side effects such as insomnia, anxiety, and, at high doses,
Amantadine is removed from
the body by the kidneys. Rimantadine is removed by the liver. This difference may have an
impact on which medicine is used to treat people who have diseases affecting
the kidneys or liver. Because side effects occur less often with rimantadine,
it may be a better choice.
Little information exists regarding how well antiviral
medicines work for treating children who have influenza A.
Antiviral medicines may need
to be given only once a day in older adults.
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
CitationsFiore AE, et al. (2011). Antiviral agents for the treatment and chemoprophylaxis of influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 60(1): 1–25.Centers for Disease Control and Prevention (2006). CDC Health Alert: CDC Recommends Against the Use of Amantadine and Rimantadine for the Treatment or Prophylaxis of Influenza in the United States During the 2005–06 Influenza Season. Available online:
July 9, 2012
E. Gregory Thompson, MD - Internal Medicine & Christine Hahn, MD - Epidemiology
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