Calcium antagonists (calcium channel blockers)

Mechanism of action of calcium channel blockers used to treat high blood pressure

As a medicine for high blood pressure, calcium antagonists (calcium channel blockers) such as Amlodipine, Diltiazem, Nifedipine, Nitrenidipine, Verapamil and similar drugs are used.

Calcium is an essential mineral because it has many functions in the body. Its best-known role is in the bones: if too little calcium is taken in through the diet or the body cannot absorb enough, the risk of osteoporosis increases. But calcium also plays an important role in blood pressure and in the electrical activation and contraction of the heart. It acts as a messenger between cells because it can enter or leave a cell through special channels in the cell membrane. These channels are especially important for blood pressure and the heart. When calcium is released from storage within a blood vessel cell, it triggers a chain of reactions that can cause the vessel to narrow and blood pressure to rise.

The effect in the heart is similar. When calcium flows into heart muscle cells, the heart muscle contracts more forcefully. Calcium also affects the heart's electrical conduction system. In the AV node in particular, it triggers the generation and conduction of electrical impulses. The faster calcium flows in, the faster the heart beats.

Calcium channel blockers: how they work

Muscle cells need calcium to contract. Calcium channel blockers inhibit the flow of calcium into the smooth muscle of the blood vessels. This causes the arteries to widen (dilate) and thus lowers blood pressure. In heart muscle cells, calcium channel blockers reduce the ability to contract (contractility) and inhibit electrical conduction, which leads to a slower pulse.

Calcium channel blockers are divided into 2 classes depending on their main site of action (some sources also list 3 classes):

Dihydropyridines (Amlodipine, Nifedipine): act mainly on the blood vessels
Medications of this type can also be used to help control symptoms of stable angina.
Non-dihydropyridines (Verapamil, Diltiazem): act mainly on the heart and on the generation and conduction of electrical impulses

Diltiazem-type calcium antagonists occupy a special place because they affect all the different target organs. In addition to being used for high blood pressure, these drugs are also used for stable angina, fast heart rhythm disorders (tachycardias) and atrial fibrillation.

In most cases, calcium antagonists are used in combination with other blood pressure medications.

Calcium channel blockers: side effects

With calcium antagonists of the dihydropyridine type (amlodipine, nifedipine), which act mainly on the muscles in the blood vessels, common side effects include fluid retention in the ankles (edema), facial flushing, increased awareness of the heartbeat (palpitations), and headaches.

With non-dihydropyridine drugs (Verapamil, Diltiazem), constipation and a slower heart rate occur more often.
It is essential to ensure that simultaneous treatment with beta blockers and non-dihydropyridine calcium channel blockers (Verapamil, Diltiazem) is only provided by experienced clinicians when specifically necessary. Normally, they should not be combined.
For complete information, please read the package leaflet.

Calcium channel blockers: active substances

Amlodipine, Diltiazem, Felodipine, Isradipine, Manidipine, Nifedipine, Nilvadipine, Nisoldipine, Nitrenidipine, Verapamil

Calcium channel blockers: examples of active substances and licensed drugs

Wirkstoff	Produkte
Amlodipin	Amlo TAD, Amlobesilat, Amloclair, Amlodigamma, Amlodipin, Biramlo Kombipräparat, BisoDipin Kombipräparat, Camlostar Kombipräparat, CandeAmlo Kombipräparat, Caramlo Kombipräparat, Copalia Kombipräparat, Dafiro Kombipräparat, Exforge Kombipräparat, LosAmlo Kombipräparat, Norvasc, RamiDipin Kombipräparat, Ramipril Kombipräparat, Ramipril/Amlodipin Kombipräparat, Sevikar Kombipräparat, Stapressial Kombipräparat, Tonotec Kombipräparat, Triveram Kombipräparat, Twynsta Kombipräparat, Viacoram Kombipräparat, Vocado Kombipräparat
Diltiazem	DiltaHexal, Diltiagamma, Diltiazem, Dilzem
Felodipin	Delmuno Kombipräparat, Felocor, Felodipin, Logimat Kombipräparat, Logimax Kombipräparat, Mobloc Kombipräparat, Modip, Triapin Kombipräparat, Unimax Kombipräparat
Isradipin	Lomir, Vascal
Lercanidipin	Carmen Kombipräparat, Corifeo, Ena-Lerca Kombipräparat, EnaCanpin Kombipräparat, Enalapril/Lercanidipin Kombipräparat, Lercanidipin, Lercaprel Kombipräparat, Zaneril Kombipräparat, Zanipress Kombipräparat
Manidipin	Manyper, Vivace Kombipräparat
Nifedipin	Adalat, Aprical, Belnif Kombipräparat, Bresben Kombipräparat, Nif-Ten Kombipräparat, Nifatenol Kombipräparat, Nife-CT, Nifedipin, NifeHexal, Nifical
Nilvadipin	Escor, Nivadil
Nisoldipin	Baymycard
Nitrendipin	Bayotensin, Eneas Kombipräparat, Jutapress, Nitregamma, Nitren-acis, Nitrendipin, Nitrepress
Verapamil	Isoptin, Tarka Kombipräparat, Vera, Veragamma, VeraHexal, Veramex, Verapamil, Veratide Kombipräparat, Veroptinstada

Sources

This article is from Tensana – the leading app since 2011, helping hundreds of thousands of people monitor their blood pressure every day. Our content is based on carefully researched, evidence-based data and is continuously updated (as of 12/2025).

Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.

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