Well, let’s talk about Beta Blockers. We
talked about these drugs both for heart failure
and also for patients with ischemic heart
disease, angina and heart attacks - myocardial
infarction. Beta Blockers block the effect
of adrenaline on the heart cells. What do
they do by that? They slow the heart rate.
They work on the sinus node and they work
on other electrical components of the heart
and they decrease the heart rate. By decreasing
the heart rate, you decrease the work of the
heart, you decrease the cardiac output, the
amount of blood coming out. So, you also lower
the blood pressure. So, Beta Blockers lower
blood pressure and they lower the heart rate.
They are not first line drugs because they're
not quite as effective as the ACE inhibitors
and the ARB’s and the thiazide diuretics.
So, sort of the front line troops in the control
of hypertension are thiazide diuretics, ACE
inhibitors, angiotensin receptor blockers.
The second line of defense is Beta Blockers.
Now, on the other hand, if you have a patient
who has ischemic heart disease and angina,
then Beta Blockers move up to first place
particularly if the patient has both hypertension
and ischemic heart disease. You also want
to lower the heart rate. So, you’re getting,
if you will, two actions for the price of
one when you use Beta Blockers in a patient
with both high blood pressure and ischemic
heart disease and those patients are extremely
common. So, Beta Blockers are very, very commonly
prescribed for these patients.
Here’s a list of a whole bunch of Beta Blockers.
They're all generic, are just about all generic
these days. The favorite one for heart failure
tends to be carvedilol. The favorite one for
blood pressure tends to be the metoprolol
or atenolol, but again, all of them work and
all of them are generic and inexpensive.
You have to watch Beta Blockers for adverse
effects. So, there’s a tendency by Beta
Blockers to actually cause fluid retention
and if that happens, if the patient has heart
failure, you might at least initially make
their heart failure a little worse. Down the
road, the Beta Blockers actually help in heart
failure, but initially when you first give
them, you may have some fluid retention.
There are a number of other potential side
effects. For example, if you’re an asthmatic,
your asthma may get worse with Beta Blockers.
Some… There are some central nervous systems
effects… central nervous system effects.
People may be a little depressed or tired who
are on Beta Blockers. And so, of course, they
can also excessively lower your heart rate
or your blood pressure so you’re very fatigued
or lightheaded and so forth. So, again, you
start with a low dose and you advance carefully
and watch for adversive effects or so called
There’s another category of drugs called
the calcium channel blockers. These drugs
are potent vasodilators. They open up the
small blood vessels in the periphery and they
markedly reduce peripheral vascular resistance.
In fact, some people who get them, you can
actually see their face becomes a little bit
flushed because the small blood vessels are
being opened up by this drug. There are two
types of calcium channel blockers. There’s
one that actually also can slow the heart
rate down, those are the so called non-dihydroperidine
calcium blockers - diltiazem and verapamil
and they’re sometimes used for control of
arrhythmias, for example, in atrial fibrillation
to help control the heart rate.
The non… The dihydroperidine calcium blockers,
drugs like nifedipine, don’t have any electrical
activity in the heart, but they dilate…
both drugs dilate the periphery and lower
the blood pressure. And so, often, particularly
in patients with kidney disease, we’ll use
a combination of an ACE inhibitor or an angiotensin
receptor blocker and a dihydroperidine calcium
blocker. That seems to be particularly effective
and actually, may preserve kidney function
in somebody who already has mild damage to
the kidney. Both those drugs are commonly
used to control high blood pressure in diabetics
who, as you know, have a high risk of kidney