Quick Overview of Heart Failure Pharmacology

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We’ll be having a quick congestive heart failure review and we’ll also go over the drugs involved in treating the condition.

Antihypertensive drugs are responsible for relieving pressure that’s being set on the heart. The aim is to basically get the heart pumping normally that it can stretch and squeeze to eject and distribute blood to different parts of the body with as little effort as possible.

Congestive Heart Failure

In congestive heart failure (CHF), there is a lot of pressure from the peripheral veins that is being pushed on the heart. A primary cause of CHF would be increased sodium in the diet. Fortunately, there are tons of medications that can take this pressure off of the heart and promote proper blood flow.

What are the drugs that help in alleviating the pressure from the heart? These drugs are categorized into A-B-C-D. What does each letter stand for?

The Drugs for Heart Failure

A is for ACE Inhibitors

ACE inhibitors act on the renin-angiotensin-aldosterone system (RAAS) in the kidneys, which are responsible for bringing the pressure from the peripheral veins and blood vessels to decrease the pressure experienced by the heart.

B is for Beta-blockers

The basic function of beta-blockers is to block the beta receptors that have sympathetic nervous system response. And since the response is sympathomimetic, it’s basically the fight or flight reaction of the body which causes increased blood pressure and heart rate.

Blocking the beta receptors will result in relaxation of the heart, resulting to decreased blood pressure and heart rate.

C is for Calcium Channel Blockers

At SimpleNursing.com, there is a separate video about calcium channel blockers showing a detailed instruction on how calcium affects your body and, specifically, your heart.

So, when you think of calcium, the first thing that would come to mind is, it’s mainly found in the bones and is required for hardening the bone structure. That said, if there is an overload of calcium, the heart will be directly affected, causing it to harden. And if that happens, it will be very difficult for the heart to stretch and squeeze blood to the different parts of the body. Therefore, calcium channel blockers block the channels responsible for heart calcification, bringing back the normal function of the heart.  

D is for Diuretics

You can think of diuretics as the agents that open up the faucet inside your body – the faucet being your kidneys. And because the urinary tract primarily functions to excrete fluid from the body, it is imperative that the kidneys are properly working to relieve the heart of unnecessary pressure due to fluid overload.

Diuretics are effective in opening up these faucets (kidneys) to release toxins and fluids out of the body. Some of the main examples of diuretics are Lasix and hydrochlorothiazide. By decreasing the amount of blood or fluid that is going inside the heart, diuretics reduce stress and workload of the heart. Diuretics are basically calming down the increased pressure being pushed on the heart to the point of normalcy.

On our next discussion, we’ll take an in-depth look at the mechanism of action of ACE inhibitors, beta-blockers, calcium channel blockers, and diuretics.

You can drop by SimpleNursing.com and gain access to tons of topics that will help you pass major nursing exams and your NCLEX®. See you there!

Volume-Decreasing Antihypertensive Meds: ACE and Diuretics

Hello.

Today, we will be focusing our senses on the difference between your volume-decreasing antihypertensive medications – ACE inhibitors and diuretics.

Usually, the challenge when dealing with volume-decreasing antihypertensive drugs is that it’s hard to tell them apart. Somewhere along your study session, there’s confusion between heart failure drugs and electrical conductivity drugs. Here, at Simple Nursing, we’ll put some sense to it the best possible way.

The Mechanisms

Technically, two mechanisms put pressure or increase stress on the heart,  namely:

  1. Heart rate = beats per minute, concerned with the contractions of the heart and cardiac output or blood flow
  2. Pressure = workload

To explain further how heart rate and pressure works, think of this scenario:

For example, you’re an accountant who works in a huge firm who is responsible for handling specific clients on a regular basis. So, let’s say you’re balancing books, doing taxes, and closing accounts. The work that you’ve done in an hour, that’s your rate.

On the other hand, the pressure depends on how much energy and time it needs for you to close an account. While there are accounts that are small which can quickly be closed after a few adjustments, there are large accounts that might need more out of you to finish. The effort that you’re exerting is your pressure or workload.

If there’s too much pressure acting on the heart, the rate is going to have a hard time to pump all that blood out. So, technically, it’s as simple as:

  • Heart rate = electrical conductivity/contractility
  • Pressure/workload = how much work the heart needs to do to push against the vascular system

Volume-Only Drugs

So, here, you should not think about drugs that affect the heart rate, electrical stimuli, contractility, and SA and AV nodes. The primary focus is on volume-only medications which directly affects in decreasing the pressure from the heart.

What are your volume-decreasing drugs?

  1. ACE inhibitors (“-pril) – mainly concerned with decreasing the fluid volume only by targeting the renin-angiotensin-aldosterone system (RAAS)

Side note: We have an extensive lecture on ACE inhibitors which introduces you to Club RAAS, involving primary characters like Aldos-Tyrone, Mr. Renin, and Angiotensin I and II. Check this lecture out; it’s a fun and informative discussion.

  1. Diuretics – helps the body to get rid of sodium and water, causing your clients pee a lot; thus, reducing the pressure on your vessel walls. There are three types of diuretics:
  • Loop diuretics – Furosemide (Lasix)
  • Potassium-sparing – Spironolactone (Aldactone)
  • Thiazides – Chlorothiazide (Diuril)

Diuretics mainly act on the distal tubules of the kidneys, the descending Loops of Henle, tapping into them to release fluid.

Client care: Watch out for the potassium level for those taking diuretics and your digitalis toxicity due to a low potassium level. Instruct clients who take diuretics to eat potassium-fortified foods.

Remember, when talking about volume-decreasing medications, only the volume is affected to decrease pressure. It has nothing to do with the rate or the electrical conductivity.

On a separate lecture, we will be thoroughly discussing the mechanism of loop diuretics. See you there!

Mechanisms of Renin-Angiotensin-Aldosterone System Pt 1

Welcome to Club RAAS, where you’ll get a dose of crucial information about ACE inhibitors and the elements that are responsible for the system’s regulation.

What are the things you can get out of this lecture?

  1. A better understanding of the renin-angiotensin-aldosterone system through Club RAAS.
  2. How ACE inhibitors break up the system to release fluid out of the kidneys that cause decreased heart congestion.

Let’s do it.

Club RAAS – The Bouncer

Aside from sweating, breathing, and vomiting, the best way for the body to expel waste is through the kidneys in the form of urine. Therefore, the kidneys play a very significant part in the relieving the pressure or workload of the heart by activating or de-activating the renin-angiotensin-aldosterone system.

From this moment, you can think of your kidneys as Club RAAS – a nightclub that has doors and a bouncer to guard those doors. So, at the main entrance of Club RAAS, there’s a bouncer whose primary responsibility is to monitor what goes in and out of club’s door. The bouncer’s name is Aldos-Tyrone (aldosterone). Aldosterone is an enzyme produced by the kidneys for fluid retention and control. Aldos-Tyrone is basically that guy who closes the doors to your club to make sure that nothing comes in or comes out.

            Club RAAS = Aldos-Tyrone (The Bouncer) = fluid retention and filtration control

Club RAAS – The CEO and The Assistant Managers

Next, we have the upper management that oversees the entire club – the CEO. The CEO in your Club RAAS is Mr. Renin, and he is located in your adrenal glands right above the kidneys. Mr. Renin is responsible for giving the orders or calling the shots, and he communicates with his assistant managers – Angiotensin I and Angiotensin II.

From the CEO to the assistant managers, the message to shut down the club is then conveyed to Aldos-Tyrone through a telephone system. The need to shut down the club and keep everyone inside is meant to boost revenue by selling drinks.

The CEO (Mr. Renin) -> Assistant Managers (Angiotensin I and II) -> Aldos-Tyrone (Aldosterone)

The Demographic

Apart from having control of the club’s entrance, Aldos-Tyrone is also responsible for overseeing the specific demographic that goes in first, and it’s the women. Here, the women represent sodium (NA). The moment these women enter Club RAAS, they will immediately be followed by the men. Men represent water (H2O).

The CEO is aware that the men are the ones who will buy drinks; thus increasing the revenue. For this reason, the CEO will instruct the bouncer to allow enough women in the club to have enough men to bring in revenue. So, this is the whole concept when it comes to the entire Club RAAS scenario.

      Aldos-Tyrone -> allows sodium (women) inside the club -> sodium attracts water (men)

The Concept

Sodium attracts water as women attract men. Therefore, if the body is feeling hypotensive, it will give a signal to your kidneys to increase pressure. Aldosterone will do its job by shutting down the kidneys and not let the sodium out but still allow for the sodium to come in. As the sodium increases so does the water; this will cause increased blood pressure.

If Aldos-Tyrone does not stop allowing women to go inside and not allowing them to come out, Club RAAS will reach its maximum capacity and will cause strain on its walls.

What happens if there is increased sodium inside the body?

  • Blood pressure will skyrocket
  • Pounding pulse
  • Fluid retention; weight gain

Ceasing the Pressure with ACE Inhibitors

To stop overloading the kidneys and the body with sodium and water, Aldos-Tyrone needs to be blocked, and to do so, angiotensin-converting enzyme (ACE) inhibitor is administered.

ACE inhibitors or your aldosterone receptor blocker cut the lines of communication between the CEO and Aldos-Tyrone. This basically means that you are blocking the renin-angiotensin-aldosterone system.

            Increased sodium and water = block aldosterone = use ACE inhibitors

ACE vs. ARB

ACE inhibitors or Sartans are used to block angiotensin I from being converted to angiotensin II. On the other hand, if you are specifically going to prevent angiotensin II from binding to the receptors, angiotensin-receptor blockers (ARBs) are used. The moment you block Aldos-Tyrone, you will now allow sodium to leave your kidneys and water will immediately follow. The result?

  • Decreased blood pressure
  • Decreased pounding pulse
  • Reduced jugular venous pressure
  • Reduced edema

There you have it. I hope lecture has helped you understand precisely how the RAAS works and how ACE inhibitors act on the kidneys to lower blood pressure. On our next discussion, we will be tackling calcium channel blockers.

See you there!