Pharm: Calcium Channel Blockers for Heart Failure & MI

Heart failure is a condition that is identified as the heart’s inefficiency to pump blood supply to various areas of the body adequately. If there is an insufficient flow of blood, all primary functions of the body are disrupted. While there are instances wherein pumping difficulties cause the heart failure, other clients suffer due to stiffening and hardening of the muscles of the heart, resulting to reduction of blood flow.

This is where calcium channel blockers come in.

Calming the Heart

Here, we are informing the sympathomimetic response of the sympathetic nervous system to calm down by instructing the heart not to contract. This is done by taking the pressure off and blocking out the stimulus.

So, there are three types of medications that you can give to achieve this, namely:

• Alpha-blockers (Catapres or Clonidine) – has vasodilation effects
• Beta-blockers
• Calcium channel blockers

Calcium Channel Blockers

As mentioned, one of the main problems with heart failure is increased volume and resistance inside the blood vessels; therefore, it is necessary that this resistance is relieved through calcium channel blockers. We are basically asking the blood vessels to relax and not be tensed.

Though Nitroglycerin is given to clients with myocardial infarction, the main goal is still taking off the electrical excitability from the blood vessels so as not to strain the heart muscles.

Cellular Level

The blood vessels are like rivers that are interlinked with each other. Looking at it at a cellular level, and taking into consideration a cell, which looks like a small city. Inside this city are various structures like the city hall (nucleus), power plant (mitochondria), trash company (lysosomes), and other parts like the Golgi apparatus, and endoplasmic reticulum.

In every city or cell, there are gates that allow elements to enter or exit, like in the case of sodium-potassium exchange. Fluids and electrolytes cause cellular excitability; calcium is an example of an electrolyte that causes tensed and constricted vessels.

Calcium: Bone versus Heart

Calcium causes bones to become stronger and more durable. Calcium for the heart, on the other hand, has a similar effect because it can cause the vessels to become stiff which would add to the resistance if there’s pressure, leading to hypertension.

Mechanism of Calcium Channel Blockers

Calcium channel blockers are given to make the heart very soft and supple. Like diuretics and beta blockers, calcium channel blockers decrease the rate and the hardness.

Calcium channel blockers are medications prescribed to relax the vessels of the heart, thereby increasing the blood supply and oxygen while reducing the workload. Some well-known calcium channel blockers are:

• Diltiazem
• Felodipine
• Amlodipine

Other heart conditions wherein calcium channel blockers are applicable:

• Hypertension
• Hypertrophic cardiomyopathy
• Coronary artery disease (CAD)

Client Teaching

When taking calcium channel blockers, you should advise your client that this type of medication has to be taken with either milk or food. Taking of blood pressure is also necessary to monitor any signs of side effects like decreased heart rate, hypotension, drowsiness, and lightheadedness.

For clients with myocardial infarction, emergency drugs are often given aside from maintenance medications. This will be discussed in our next article.

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