What are Calcium Channel Blockers?

We did a couple of videos and articles discussing calcium channel blockers. But here, we’ll solely focus on calcium channel blockers as a negative chronotropic drug.

So, the primary goal of calcium channel blockers is to stop the depolarization or the contractility of the vessels of the heart, bringing the organ to a relaxed state.

Calcium Channel Blockers as a Negative Chronotropic

One of the notable characteristics of calcium channel blockers is that these drugs act as a negative chronotropic which is mainly focuses on the heart rate. Negative chronotropic drugs cause decreased electrical stimuli but do not deplete volume.

The “-Pine” and “-Zem” Drugs

An easy way to identify calcium channel blockers is to remember drugs ending in “-pine.” Most of the calcium channel blockers like Amlodipine (Norvasc), Nifedipine (Procardia), or the most popular, Diltiazem or Cardizem which is another popular drug used in hospitals.

The Indications

Clients who have experienced myocardial infarction or heart attack are given calcium channel blockers to soften up their hearts and relieve it of its hard contractions. Basically, we are also preventing the client’s potential to go into a hypertensive crisis. Calcium channel blockers are the best standard of care when dealing with heart attack clients.

Crucial Pointers

There are a couple of important things that you have to remember when administering calcium channel blockers or taking care of clients who are getting the treatment.

Check the BP and HR

Two of the most important things that nurses have to consider before giving calcium channel blockers are the client’s blood pressure and heart rate. It is advisable to check these two factors at least 30 minutes before the drug is given. Why?

A good example would be this hospital scenario:

A client has a low blood pressure of around 105/50. The client is supposedly getting blood pressure medications because her BP has been trending with a 105 systolic pressure for three days. Typically, the doctor will order blood pressure medications to decrease the client’s chances of going into hypertensive crisis.

Upon checking the blood pressure in the morning, the blood pressure is now up to a 115 systolic pressure so, as the nurse in charge, you will take note of that. With that BP, there is no need to withhold the drug. However, an hour or 30 minutes before the drug was given, the BP dropped to 82/40. So, the blood pressure medication will not be given at that moment.

The scenario provided above is a typical situation with hypertensive clients. For this reason, it is important to check the blood pressure and heart rate before giving any anti-hypertensive medications.

Take note: If you somehow obtained a bad vital sign reading with the client’s blood pressure, you have to retake using the other arm.

Low Blood Pressure

If a hypertensive client’s BP significantly drops, you should:

• Withhold the medication
• Inform the doctor
• Put the client in Trendelenburg position
• Advocate for an IV bolus to incorporate more fluids to the client
• Re-check the blood pressure

Only hold the medication if the client’s blood pressure drops below 100 systolic pressure.

With or Without Meals?

Unlike other medications, calcium channel blockers are always given with meals. Food helps in the proper absorption of the medication.

That’s the end of our calcium channel blocker lecture. Our next pharmacology lecture will focus on diuretics.