Each
winter, millions of people suffer from the flu. Epidemics of influenza
occur during the winter months nearly every year and are responsible
for an average of approximately 20,000 deaths per year in the U.S.
It spreads easily from person to person mainly when an infected person
coughs or sneezes. Flu - A short name for influenza - is caused by
viruses that infect the nose, throat, and lungs. It usually is a mild
disease in healthy children, young adults, and middle-aged people.
However, flu can be life threatening in older adults and in anyone
who has chronic illnesses such as diabetes, heart, lung, or kidney
disease
The
flu shot is the primary method of preventing and controlling the flu.
However, four drugs have been approved to treat people who get the
flu: amantadine (Symmetrel), rimantadine (Flumadine), zanamivir
(Relenza), and oseltamivir (Tamiflu).
Amantadine and rimantadine are indicated for the prevention
and treatment of Influenza A. When used to prevent the flu in healthy
adults or children, both amantadine and rimantadine
are approximately 70 percent - 90 percent effective in preventing
Influenza A infection. Zanamivir and oseltamivir are
effective against both Influenza A and B viruses. Both were approved
in 1999 for treatment of influenza, but neither is approved for prevention.
The four drugs differ in terms of side effects. In some patients,
amantadine can cause nervousness, difficulty concentrating,
or lightheadedness. Rimantadine can also cause the same type
of side effects, but less frequently. Zanamivir should be used
with caution in people who have asthma or chronic obstructive pulmonary
disease, because some people with asthma or COPD may have difficulty
breathing after using zanamivir. Oseltamivir can cause
nausea and vomiting in some people. These drugs are effective against
influenza viruses, but they are not effective for illnesses caused
by other viruses or bacteria that can have symptoms similar to influenza.
When taken within 2 days of flu onset in healthy adults, amantadine
and rimantadine can reduce the severity and duration of
signs and symptoms of influenza A illness, and zanamivir and
oseltamivir can reduce the duration of uncomplicated influenza
A and B illness by approximately one day. To reduce the emergence
of drug-resistant flu strains, amantadine or rimantadine
treatment should be stopped as soon as possible, generally within
24 - 48 hours after the disappearance of flu signs and symptoms. The
recommended duration of treatment with either zanamivir or
oseltamivir is 5 days.
None of these medications is a substitute for the flu shot, but should
be considered for the following special situations.
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