Examples
|
| Symmetrel | amantadine |
| Flumadine | rimantadine |
How It Works
These antiviral medicines prevent the
spread of type A
by interfering with the production of the
virus inside the body. They do not treat or protect you against influenza
B.
Why It Is Used
These antiviral medicines reduce the
severity of influenza (flu) symptoms and shorten the course of the illness of
influenza A. 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 (Symmetrel) 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.
How Well It Works
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.
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.
Side Effects
Side effects have been reported with
both amantadine and rimantadine:
- Amantadine can cause sleeplessness (),
, and agitation in a small number of
people (2%).
- Rimantadine often causes side effects that affect the
digestive system, such as an upset stomach, nausea, and loss of
appetite.
More serious but less frequent side effects (seizures,
confusion) have been reported in older adults and, most commonly, in adults who
have seizure disorders. Lowering the dose reduces these side effects without
reducing the effectiveness of the medication.
Side effects
decrease after about 1 week of use and reverse as soon as treatment
stops.
See Drug Reference for a full list of side effects. (Drug
Reference is not available in all systems.)
What To Think About
Amantadine and rimantadine are
effective only against some type A influenza viruses.
Amantadine
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,
seizures.