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Jul 5, 2022

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Calcium Channel Blockers and High Blood Pressure

Do you struggle with high blood pressure, chest pain or irregular heartbeat? If that is the case, then calcium channel blockers (CCBs) may be a suitable medication for you.

What are Calcium Channel Blockers (CCBs)?

Calcium channel blockers, also known as calcium channel antagonists, are frequently prescribed to lower blood pressure. They are also used to treat a variety of conditions such as:

How do CCBs Work?

Calcium channel blockers decrease the amount of calcium that enter the heart and blood vessel walls. This relaxes the blood vessels and makes it easier for the heart to pump resulting in decreased blood pressure.

When calcium dissolves in water, it becomes an electrolyte, meaning it carries a positive charge. Ions (electrically charged atoms) in electrolytes are used by your body to move substances into and out of your cells.

This is fundamental because calcium is required for the muscular linings of your blood vessels throughout your body to contract, in particular, the arteries that supply your heart with oxygen. Calcium enters these cells through ion channels, which are small openings on your cell's surface. CCBs then block these channels, decreasing the amount of calcium entering cells in your heart and blood vessel walls. Subsequently, your blood vessels relax/widen (vasodilation) and your heart muscle acquires more oxygenated blood. Thus, allowing CCBs to decrease your blood pressure, and treat angina (chest pain).

How Calcium Channel Blockers Work

Calcium Channel Blocker Subclasses

Dihydropyridine (DHP) CCBs vs. Non-Dihydropyridine (Non-DHP) CCBs

CCBs are categorized into 2 classes called Dihydropyridine—'dai·hai·drow·pai·ruh·deen'—(DHP) CCBs and Non-Dihydropyridine (Non-DHP) CCBS.

There are considerable distinctions between DHP and non-DHP medications, including toxicity levels, hemodynamic (relating to blood flow) side effects, and drug interactions.

DHP CCBs tend to be more aggressive vasodilators of the two. Non-DHPs seem to have potential advantages for patients with chronic kidney disease and diabetic nephropathy.

Not all generic medications are therapeutically equivalent to the brand name medications. If your pharmacist is substituting a generic medication for a brand name medication, they should check the FDA Orange Book and choose a generic product that is AB-rated to the brand name.


This specific class of medications typically ends in “-pine.” DHP CCBs are used to treat hypertension (high blood pressure), chronic stable angina (long-term pain and/or discomfort in your chest that is most commonly associated with physical exercise or emotional stress), and Prinzemetal’s angina, which is a form of unstable angina that is characterized as chest pain during rest.

Medications in DHP family

Amlodipine (Norvasc) 2.5–10 mg daily
Considered the safest if a CCB must be used to lower blood pressure in individuals with heart failure with reduced ejection fraction (HFrEF—occurs when the muscle of the left ventricle is not pumping as well as normal)

Watch Ask Marley Drug video on Amlodipine. Dee, one of our pharmacists, answers 5 common questions about the medication.

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Felodipine ER (extended-release) 2.5–10 mg daily

  • Extended-release (ER)—should never be chewed, cut, crushed, or dissolved
  • Considered the safest if a CCB must be used to lower blood pressure in individuals with heart failure with reduced ejection fraction (HFrEF)

Nifedipine ER (Adalat CC, Procardia XL) 30–90 mg daily

  • Adalat CC should be taken on an empty stomach
  • Adalat CC and Procardia XL may leave an empty shell in your stool. If you see the tablet in your stool, it is very common, and should not be worried about
  • Extended-release (ER)—should never be chewed, cut, crushed, or dissolved
  • Considered the drug of choice in pregnant women

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Nifedipine IR (immediate release) (Procardia) 30–90 mg daily

Isradipine 2.5–10 mg BID (twice a day)

DHP CCBs mainly work on the vascular smooth muscle and your myocardial cells, causing peripheral arterial vasodilation (widening/relaxation of your blood vessels) and coronary artery vasodilation (widening/relaxation of the arteries that surround your heart).

The peripheral arterial vasodilation leads to common side effects such as:

  • Reflex tachycardia (your heart beats faster in response to the stimulus of lower blood pressure)
  • Headache
  • Flushing (transient, involuntary reddening of the skin, most commonly seen on the face)
  • Peripheral edema (swelling of your lower legs or hands)

Other common side effects seen with DHP CCBs include:

  • Gingival hyperplasia (overgrowth of gum tissue around the teeth)
  • Dizziness
  • Lightheadedness
  • Blood pressure fluctuations

Non-DHP CCBs — ending in '-pine'

Non-DHP CCBs are primarily used to control heart rate in certain arrhythmias, such as atrial fibrillation, and are sometimes used for hypertension and angina. This medication drug class inhibits calcium ions from entering the vascular smooth muscle and myocardial cells, but they are more selective for the myocardium (heart muscles) than the DHP CCBs.

Medications in non-DHP family

Diltiazem (Cardizem, Cardizem CD, Cardizem LA, Cartia XT, Tiazac) 120–360 mg daily

CD—controlled release; LA—long acting; XT—extended release

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Verapamil (Calan, Calan SR, Verelan, Verelan PM) 240–480 mg daily

SR—sustained release
  • Verapamil is more useful than other CCBs in the treatment of cluster headaches and preventing migraines, however, it takes approximately 2 weeks to work
  • Causes more constipation
  • Calan SR: daily dose can be given every morning and at night
  • Verelan PM: daily dose given every night at bedtime

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Warning with Non-DHP CCBs:
Non-DHP medications have a negative inotropic effect (decrease the force of ventricular contraction) because they tend to lower calcium levels and interfere with cardiac function. Non-DHP medications should not be taken by patients with cardiovascular problems, such as heart failure, because they may worsen symptoms.

Common side effects seen with Non-DHP include:

  • Edema (swelling)
  • Constipation - more common with Verapamil
  • Gingival hyperplasia
  • Tiredness
  • Headache
  • Dizziness

What Should I do If I Miss a Dose?

If you forget to take a dose, take it as soon as you remember unless it's almost time for your next dose. In this case, skip the forgotten dose and take the next one at the usual time. Do not take 2 doses together to make up for a missed dose.

If you take more than your doctor prescribed, you may experience fatal symptoms such as shortness of breath, chest pain (sudden change in intensity or frequency of pain), heart palpitations where you can feel your heartbeat racing/pounding, and/or fainting. You should seek immediate medical care if you have any of those symptoms.

Are There Any Interactions I Should be Aware of?

Certain drugs may interfere with the effectiveness of your medication. They may potentially be the source of additional health issues. These include:

  • Histamine antagonists, such as cimetidine (Tagamet), have been shown to inhibit the metabolism of CCB medications. Lower doses of CCB are recommended when used concurrently with these medications
  • Avoid grapefruit & grapefruit juice when taking CCBs because they have been shown to boost the effects of some CCBs, and may increase the risk of side effects.
  • Beta-blockers. In some cases, beta-blockers and CCBs have been used together with increased efficacy. However, due to the decrease in cardiac muscle contractility and slowing of the cardiac rhythm, co-administration may cause more negative effects. Hypotension, bradycardia, and heart failure should be routinely monitored in individuals taking CCBs and beta-blockers.
  • Smoking should be avoided while taking CCBs due to the potential to cause tachycardia (increased heartbeat).

Speak With Your Doctor

Every year, millions of adults in the United States are prescribed CCBs. Serious side effects with CCBs are considered rare and uncommon. They are generally regarded as a drug class that is both safe and effective.

Talk to your healthcare provider today and send your prescription to Marley Drug. Save up to 95% compared to your local pharmacy by using Marley Drug.

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