Antihypertensive Medication: Calcium Channel Blockers – Part 2

Calcium channel blockers are antihypertensive medications that technically reduce hypertension or blood pressure; thus, relieving stress from the heart.

How does one quickly spot a calcium channel blocker?

More often than not, calcium channel blockers end in “-pine.” Not to be confused with another antihypertensive medication known as beta-blockers that end in “-lol.” The most popular calcium channel blocker used in a hospital setting, which doesn’t end in “-pine” is Cardizem (Diltiazem). Cardizem drip is given to clients who have significantly high blood pressure and suffers chronic stable angina or chest pain.

Anatomy of the Heart

How do calcium channel blockers relieve the pressure on the heart that results to smooth contraction? All your questions will be answered momentarily but first, let’s do quick anatomy and physiology of the heart.

The heart’s primary responsibility is to pump blood. Think of the heart as a pumping station that pumps fuel to a car, the car is your body. Blood is composed of nutrients as well as oxygen. If the heart is dysfunctional, blood will not be sufficiently pumped, and the organs will malfunction which leads to the deterioration of the system.

Now, the veins vacuum deoxygenated blood into the heart to be re-oxygenated while the arteries send oxygenated blood away from the body. So remember:

• Veins – Vacuum
• Arteries – Away

The left ventricle, one of the main chambers of the heart, is the chamber that is mainly responsible for pumping oxygenated blood throughout the entire body. For this reason, the left ventricle is the thickest and the largest chamber of the heart.

If the peripheral vessels (arteries) are stiff, this causes the left ventricle to push hard against the resistance. If this happens, a lot more energy is required, and the left ventricle exerts more stress to pump more blood into the system.

If there was less resistance, the heart does not suffer. The tendency is for the heart to push as much as it can just to suffice different parts of the body with the blood it needs to function correctly. To lessen the strain on the heart and bring the blood pressure down, you need your calcium channel blockers.

How does calcium works inside the body?

Blood vessels are composed of epithelial cells. Imagine that every cell operates as a city – it has walls, a city hall, a cleaning or trash department, a post office, and gates. The central area that we will be focusing on is the city gates which are known as “channels” of the cell. The primary functions of these barriers are:

• Break down enzymes
• Allow enzymes into the cell
• Releases enzymes from the cell

One of the main channels that you want to block in cases of hypertension is calcium. Why do you want to prevent calcium from coming inside the cell? This is because calcium is a mineral that contributes to the following:

• Cellular connection
• Blood clot
• Muscle contraction
• Nerve function
• Teeth and bone strength

Calcium hardens the cells which then makes the arteries rigid. Increased cardiac output and stroke volume are two identifiers that the left ventricle is putting a lot of effort to pump blood into the stiff vessels.

Mechanisms of calcium channel blockers

This is where calcium channel blockers come in. Calcium channel blockers prevent calcium from entering the cells which lessens the cell’s hardness thereby making the blood vessels or the highways of the heart more flexible. It is now easier for the left ventricle to push blood out of the heart and into the vessels resulting to lower blood pressure.

For those who haven’t had a copy of the Pathophysiology Bible, get yourself a copy now. It contains more 70 concept maps that you can utilize for your clinical days. Concept maps vary from nursing outcomes, interventions, signs and symptoms, and pathophysiology of the Top 70 diagnoses of common admissions inside the hospital. With the Pathophysiology Bible, your study time will be cut by 200%.

For our next discussion, we will be tackling Nitroglycerin and vasodilators. See you on our next lecture!