00:01
A new category of drugs
in the management of angina
are the pFOX inhibitors.
00:05
Now, these drugs are
Partial fatty acid
oxidation inhibitors
or pFOX inhibitors.
00:13
It increases the efficiency
of oxygen utilization
and it shifts energy production from
the fatty acids over to glucose.
00:21
There may also be an effect
on the slow sodium channels
within the heart.
00:28
We're not entirely
sure of this,
but it's certainly one of
the potential mechanisms.
00:34
Despite this, ranolazine
has little effect on heart rate
or contractility.
00:39
The next category of drugs
are what we colloquially refer to
as funny channel inhibitors.
00:45
Ivabradine is at this point in time,
one of the few agents that do this.
00:50
It inhibits the
slow sodium/potassium channel
of the sinoatrial node
or the IK current.
00:56
We call it funny channel because
of the appearance of this channel
on electron microscopy,
and also the behavior of it.
01:04
So the scientists that
first discovered it called it
the funny channel.
01:08
Now, this particular agent
has many different trade names
in many different countries.
01:13
So, when you are looking up
the drugs in your own country,
have a look at my list there
and I've got the trade names listed
for each of the major countries.
01:23
What you see with this medication
is that it reduces the heart rate
because it reduces that
pacemaker slow and recurrent.
01:31
There's no real change
in inotropy
it just really reduces
the heart rate
and it's particularly effective.
01:38
It's used predominantly
in angina, and in heart failure.
01:41
It's also used in inappropriate
sinus tachycardia.
01:44
Now, when we take a look at
the effectiveness of this agent
in angina
versus, say a beta blocker,
we found that it was actually
more effective than a beta blocker
and as effective as some of our
calcium channel blockers.
01:57
In terms of the adverse event rates
of this medication,
there is something called
luminous phenomena.
02:04
And it's a very bizarre
kind of a description.
02:07
Patients describe
walking around in a bright haze.
02:11
So they feel that, say a light
has a more luminous quality to it,
it has more
of a fuzzy quality to it,
and they walk around
and they feel like
they're in a
highly lit up corridor.
02:24
So, it's a strange
kind of sensation.
02:26
It's hard to put into words,
but when your patients come to you
and complain about it,
it's worthwhile
listening to them.
02:32
I also want to
point out as well,
that this is something
that will be on exams
because it's such a unique phenomena
related to this drug.
02:41
Of course, it's going to cause
some patients to have
excessive bradycardia.
02:46
It may cause an AV block,
it can cause dizziness
due to either low heart rate
or low blood pressure,
and it can cause a blurred vision
that is separate and different
from the luminous phenomena
that I was talking about.
02:59
Now, we don't want
to use this agent
in patients who already
or excessively bradycardic
or have Sick sinus syndrome.
03:05
We don't want to use this agent
or we want to use this agent
with caution
because other agents
who are CYP 3A4 inhibitors
can interfere with the area
under the curve.
03:17
So an example of that is, say
ketoconazole, or macrolides.
03:22
We want to be aware
that it can have an interaction
with verapamil or diltiazam,
as well.
03:29
Now, remember that
we're using this agent in patients
who have heart failure, as well,
with cardiac reserve.
03:37
We also have to be cautious
in patients
who have underlying
tachycardia
because you sometimes
can exacerbate an arrhythmia.
03:43
And finally,
you have to be aware
that we don't want to use this
medication in atrial fibrillation,
because the indications
are specifically excluding
atrial fibrillation
in the United States, and Canada.
03:55
So, be aware
that there are some limitations
with using this drug.
04:00
Okay, that's great.
04:01
You managed to make it
through this lecture,
you did really well.
04:04
I know that you're going to do
really, really well in your exams.
04:07
Go in there with confidence
and show them what you know.