So the treatment really boils
down to the M2 inhibitors,
either amantadine or rimantadine,
and these are primary symmetrical amines
as you can see from their structure.
They only work for influenza A.
And unfortunately, in recent years,
the strains of influenza
that are going around,
and they’re having antigenic drift now.
But the ones that are going around are
resistant to amantadine and rimantadine.
Newer strains may emerge
that are susceptible.
And the way they work is they mess
up this M2 ion channel activity
and they inhibit, therefore, the
virus uncoating inside the cell.
That’s the way they work.
And they’ve got some side effects.
They’ve got insomnia, vertigo,
and difficulty concentrating.
And if you can imagine giving
these drugs to elderly persons
who may already have problems sleeping,
who are already unsteady on their feet,
or may also have problems with cognition.
So these are difficult.
Nevertheless, if the virus is susceptible,
they certainly work to some degree,
especially in the
Therapy wise, you have to
start an anti-influenza drug
within 24 to 48 hours to
get any real good effect.
Now, back to viral
remember I told that as the
virus tries to emerge,
it has to destroy the sialic acid
on the respiratory epithelium.
And that prevents the
hemagglutinin spike from sticking
to an infected cell so it
allows the virus to emerge.
So once it can get out it
can go to the next cell
and then it can move down the
respiratory tree as we described.
So now that tells us about the
So here’s the way neuraminidase works,
it cleaves the receptor and
new viruses are released.
But the neuraminidase inhibitors,
what they do is they block the
ability of the neuraminidase
to destroy sialic acid
so the virus can’t really emerge
and infect the adjacent cell.
That’s how they work.
And they work against both A and B.
Remember, rimantadine and
amantadine only worked against A.
And there are two drugs that are
available, one is oseltamivir,
which is given in an oral pill,
and zanamivir works in identical fashion,
but it’s given as an inhaled drug
and so it gets to the influenza
virus where the action is.
Oseltamivir has to get
there via the circulation.
So the side effects of
each should be mentioned.
The common side effects would be
nausea and vomiting, GI upset.
Rarely, the patients would get rash,
arrhythmias, seizures, confusion, or
occasionally aggravation of their diabetes.
You picture zanamivir is having a
problem because of its inhalation.
And so commonly a patient will
get a cough, bronchospasm,
may cause an inflammatory process in
the bronchial tree with bronchitis
and nasal congestion.
Rare, it can cause
delirium and confusion.
So those are the drugs that
we use to treat influenza.