- Hello Jeff -
-
- This should come as no surprise.
-
- How do Amantadine and Rimantadine work? "Amantadine
and rimantadine are thought to interfere with influenza A virus M2 protein,
a membrane ion channel protein, and inhibit virus uncoating, which inhibits
virus replication, resulting in decreased viral shedding."
-
- Influenza viruses are "smart" viruses. They
learn to hide and evade antiviral medications. I am convinced that in
the near future we will see influenza become resistant to the neuraminidase
inhabitors as well.
-
- "Zanamivir and oseltamivir block the active site
of the influenza viral enzyme neuraminidase, which is common to both influenza
A and influenza B viruses. This effect results in viral aggregation at
the host cell surface and reduces the number of viruses released from the
infected cell."
-
- Overuse and misuse of these products is directly responsible
for the resistance and mutation in seasonal flu and avian influenzas as
well.
-
- Patricia Doyle
-
-
- Flu Virus Resistant To 2 Drugs, CDC Says
By Daniel Yee
1-15-6
-
- ATLANTA (AP) -- The government, for the first time, is
urging doctors not to prescribe two antiviral drugs commonly used to fight
influenza after discovering that the predominant strain of the virus has
built up high levels of resistance to them at alarming speed.
-
- A whopping 91 percent of virus samples tested by the
Centers for Disease Control and Prevention this flu season proved resistant
to rimantadine and amantadine, a huge increase since last year, when only
11 percent were.
-
- The discovery adds to worries about how to fight bird
flu should it start spreading among people. Health officials had hoped
to conserve use of two newer antiviral drugs, Tamiflu and Relenza, because
they show activity against bird flu, unlike the older drugs.
-
- Now, because of the resistance issue, the newer drugs
are being recommended for ordinary flu, increasing the chances that resistance
will develop more rapidly to them, too, as they become more commonly used.
-
- The newer drugs work against Type A and B influenza strains;
the older ones work only against Type A, but cost less and are available
in generic form.
-
- CDC officials took the unusual step of calling a Saturday
news conference to announce that the predominant strain this season _ the
type A H3N2 influenza strain _ was resistant to the older drugs.
-
- "Clinicians should not use rimantadine and amantadine
... because the drugs will not be effective," said CDC director Dr.
Julie Gerberding.
-
- She said the lab tests, which CDC scientists had been
analyzing since Friday, surprised health officials and the health agency
rushed to get the word out.
-
- "I don't think we were expecting it to be so dramatic
so quickly this year," Gerberding said. "We just didn't feel
it was responsible to wait three more days during a holiday weekend to
let clinicians know."
-
- The CDC tested 120 influenza A virus samples from the
H3N2 strain and found that 109 were resistant to the two drugs. Two years
ago, less than 2 percent of the samples were resistant. Last year, 11 percent
were.
-
- Gerberding said the agency didn't know how the resistance
occurred, saying it may have been the result of a mutation in the virus
or overuse of the drugs abroad, such as in countries that permit the drugs
to be purchased without a prescription.
-
- One flu expert, Dr. William Schaffner of Vanderbilt University,
said the development was "disconcerting" as flu now has joined
the ranks of other diseases, such as tuberculosis and HIV, that recently
have acquired the ability to resist front-line medications.
-
-
- Patricia A. Doyle, DVM, PhD- Bus Admin,
Tropical Agricultural Economics
- Please visit my "Emerging
Diseases" message board.
-
- Also my new website:
- http://drpdoyle.tripod.com/
-
- Zhan le Devlesa tai sastimasa
Go with God and in Good Health
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