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Flu (Influenza)
The classic symptoms of flu are headache, chills, and dry cough
followed by body aches and fever.
Denis Belanger, Pharmacist, Drug Information Specialist,
Ottawa Valley Regional Drug Information Services
The flu is an acute respiratory infection caused by a variety
of influenza viruses. Flu differs from the common cold, a respiratory
infection caused by viruses, in several ways. Although the flu
season runs from October to June, the months with the highest
activity are January, February and March. Outbreaks of flu usually
begin abruptly. As it spread through communities, the number
of cases peaks in about three weeks and subside after another
three to four weeks. During an outbreak it can affect from 20%
to 50% of the population. Most people who contract the disease
will recover within a week. However, for some people (i.e., the
elderly, newborn babies and people with certain chronic diseases)
the flu and its complications can be life-threatening.
Flu viruses are spread from person to person, usually by airborne
droplets of respiratory fluids produced by coughing and sneezing.
The viruses enter the body through the mucous membranes of the
eyes, nose and mouth. Symptoms usually appear after two to four
days, and individuals are considered contagious for another three
to four days after the first symptoms appear.
The classic symptoms of flu are headache, chills, and dry cough
followed by body aches and fever. The fever usually declines
on the second to third day. By the third day upper respiratory
symptoms such as nasal congestion and sore throat appear. a common
cold rarely causes fever, headaches and extreme exhaustion, and
the aches and pains of a cold are much milder than those caused
by the flu. Doctors usually diagnose the flu based on symptoms
and whether the flu is epidemic in the community.
Treatment usually consists of bed rest, drinking plenty of fluids
and taking medications like ASA (Aspirin) and acetaminophen to
relieve fever and discomfort. Children should not be given ASA
due to the potential risk of Reye's syndrome. Recently, two new
drugs - zanamivir (Relenza) and osetlamivir (Tamiflu) -were approved
in Canada for the treatment of uncomplicated acute illness caused
by influenza A and B viruses in patients that have been symptomatic
for no more than two days. Zanamivir is approved for persons
aged 12 and older and osetlamivir is approved for persons 18
years and older. In clinical trials both drugs shortened the
duration of symptoms by about one day. Both drugs are taken twice
daily for five days. Amantadine is another medication that can
be taken to shorten the duration of acute illness associated
with flu.
All three medications have also been studied for the prevention
of flu. Yearly vaccination against the influenza viruses, however,
remains the best method of preventing the development and spread
of flu.
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The information in this newsletter was prepared and reviewed
by pharmacists for the Canadian Pharmaceutical Journal.
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Ask Your Pharmacist newsletter is produced through
an unconditional educational grant from APOTEX/PACE. |
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