PTCB Guide to Calcium Channel Blockers.

What gets tested on the PTCB exam?

Calcium channel blockers (CCBs) are one of the most important drug classes in the treatment of cardiovascular conditions. As such, they are widely tested on the PTCB exam.

In this week’s guide, we review the key details pharmacy technicians are required to know:

• Indications – what calcium channel blockers are used to treat
• Mechanism of action – how they work
• Side effects and important adverse effects
• Key drug interactions
• Currently available brand names

As with all top 200 medicines, it’s essential to consider key details of each drug class and to avoid studying any drug class in more detail than is required. This is also true of calcium channel blockers.

For the PTCB exam, there are four key calcium channel blockers to consider:

• Nifedipine
• Amlodipine
• Diltiazem
• Verapamil

The first two drugs (nifedipine, amlodipine) are classified as dihydropyridine whereas the last two drugs (diltiazem, verapamil) are classified as non-dihydropyridine. Whilst pharmacy technicians aren’t required to know these two terms, this classification is important because each set of drugs is typically used to treat different cardiovascular conditions.

Indications.

As we learned, calcium channel blockers are primarily used to treat cardiovascular conditions. These include:

• Hypertension – or high blood pressure. Amlodipine and nifedipine are typically the CCBs used to treat this condition.
• Angina – all calcium channel blockers can be used to control symptoms in patients with this condition.
• Supraventricular arrhythmias –verapamil and diltiazem only are used to treat this indication.

Furthermore, nifedipine is also used as a tocolytic agent.

Tocolytic drugs are medicines that act as labor suppressants – sometimes known as anti-contraction medicines. By suppressing premature birth it means that other drugs, such as dexamethasone, can be used to promote fetal lung maturation, making it more clinically stable for birth to occur.

How do calcium channel blockers work?

On the PTCB exam, technicians will not be asked detailed questions on the pharmacology of calcium channel blockers.

However, technicians should have some understanding how this medicine class works. Knowing the science behind how the class works also helps to understand why many side effects and drug interactions occur.

• As their name suggests, calcium channel blockers reduce entry of calcium ions (Ca²⁺) into vascular and heart cells.
• By reducing the concentration of calcium inside these cells, CCBs cause relaxation of arterial smooth muscle.
• With arteries now relaxed and dilated, the pressure within those arteries is reduced. This explains why CCBs are useful in the treatment of hypertension.
• In addition, CCBs slow the rate of ventricular contraction (the lower two chambers of the heart). This explains why calcium channel blockers are effective in the treatment of cardiac arrhythmias.

Not all calcium channel blockers act in precisely the same manner:

• Dihydropyridines, such as amlodipine and nifedipine, are more selective for the vasculature – meaning blood vessels.
• Non-dihydropyridines, such as verapamil and diltiazem, are more selective for the heart.

Again, this makes sense if you consider that dihydropyridines are primarily used for hypertension whereas non-dihydropyridines are mostly used to treat cardiac arrhythmias.

Side Effects and Key Interactions.

Common side effects of calcium channel blockers include:

• Facial flushing
• Ankle swelling / peripheral edema
• Palpitations
• Headache
• Constipation
• Gingival hyperplasia (gum overgrowth)

Note that gum overgrowth and constipation are much more common with verapamil.

In more serious, but rarer situations – CCBs can cause bradycardia, heart block, and cardiac failure. This risk of heart failure, bradycardia, and asystole (a “flat-line”) is more likely if CCBs are taken with beta-blockers.

What brand names are currently available (2026)?

For the PTCB exam, technicians should be able to identify the following major brand names of each calcium channel blocker:

PTCB Exam-Style Questions.

Below you can find four sample PTCB exam questions on the topic of calcium channel blockers.

These four questions reflect the type of questions that get tested about duplications on the exam – both the style and difficulty. As always, have a go at the questions yourself before comparing your answers with the explanations (in the section below).

Question 1.

Nifedipine is a drug used in the treatment of which condition?

a. Cluster headaches

b. Inflammatory bowel disease

c. Hypertension

d. Acute coronary syndrome

Question 2.

What is the active ingredient of the medicine, Norvasc?

a. Amlodipine

b. Verapamil

c. Diltiazem

d. Felodipine

Question 3.

Verapamil is associated with which of these side effects?

a. Blurred vision

b. Low white blood cell count

c. Constipation

d. Cold extremities

Question 4.

Which of these drugs is used in the treatment of cardiac arrhythmias, such as atrial fibrillation?

a. Amphotericin B

b. Diltiazem

c. Metoclopramide

d. Lamotrigine

Answer Explanations.

Answer to Question 1 – c. Hypertension

As a calcium channel blocker, nifedipine is used in the treatment of cardiovascular conditions such as high blood pressure and angina.

Answer to Question 2 – a. Amlodipine

Amlodipine is the active ingredient of the medicine, Norvasc.

Answer to Question 3 – c. Constipation

Up to 10 percent of patients taking verapamil will experience constipation.

Other side effects of CCBs include fluid build-up in the extremities (peripheral edema), facial flushing, and headache.

Answer to Question 4 – b. Diltiazem

Diltiazem is the only calcium channel blocker listed among the four answers provided. Diltiazem is widely used to treat cardiac arrhythmias such as atrial fibrillation.

Amphotericin B is an antifungal drug, and lamotrigine is an anticonvulsant agent. Metoclopramide is used to treat nausea/vomiting as well as to relieve symptoms of gastroesophageal reflux disease (GERD).

PTCB Cheat Sheet on Calcium Channel Blockers.

Over the course of this week’s guide, we learned that:

• Calcium channel blockers (CCBs) are drugs used in the treatment of cardiovascular diseases such as high blood pressure (hypertension) and cardiac arrhythmias.
• Examples of CCBs include nifedipine, amlodipine, verapamil, and diltiazem.
• Nifedipine and amlodipine are classified as dihydropyridine CCBs and are primarily used to treat vascular-based disorders such as hypertension.
• Verapamil and diltiazem are classified as non-dihydropyridine CCBs and are primarily used to treat heart-based disorders such as arrhythmias.
• Nifedipine is also used as a tocolytic agent to suppress premature labor.
• Calcium channel blockers work by reducing the concentration of calcium ions (Ca²⁺) inside cells – relaxing arterial smooth muscle. With arteries now relaxed and dilated, the pressure within those arteries is reduced. CCBs also slow the rate of ventricular contractions.
• Side effects of CCBs include facial flushing, peripheral edema (fluid build-up in the legs; ankle swelling), constipation (particularly verapamil), headache, palpitations, and gum overgrowth (gingival hyperplasia).
• CCBs should be avoided with beta-blockers because the combination can cause heart failure and severe bradycardia (very slow heart rate).
• Nifedipine is the active ingredient of Adalat. Amlodipine is the active ingredient of Norvasc. Diltiazem is the active ingredient of Cardizem and Dilacor. Verapamil is the active ingredient of Verelan.

Hope you found this week’s PTCB guide to calcium channel blockers useful!

Master every topic of the PTCB exam by becoming a full member of our test prep program – everything you need to succeed at your pharmacy technician exam.