Verapamil (verapamil hydrochloride) is a so-called calcium channel blocker or calcium channel antagonist. Verapamil belongs to the group of calcium channel blockers, which act on the calcium channels of the blood vessels as well as the channels around the heart. Verapamil is thus opposed to the group of calcium channel blockers which only affect the vascular channels (nifedipine type). For this reason, verapamil is frequently used in the treatment of cardiovascular diseases. In principle, the mechanism behind the drug’s mode of action is that a calcium channel is blocked, which plays a decisive role in the contraction of the heart and the muscle tension of the vessels.
Mode of action
Calcium is a mineral that is essential for the human body. It sometimes ensures that the heart muscle can contract correctly and that the vessels in the body have the correct and necessary muscle tension. The calcium influx ensures that the muscle fibers are sufficiently concentrated.
The so-called calcium channel blockers such as verapamil can block a calcium channel in the cell and thus have a direct effect on the strength of the heart muscle and the muscle tension of the vessels. By blocking the channel, calcium can no longer flow into the cell interior and the strength of the muscles of the heart as well as the muscles located in the vessels decreases. This is due to the so-called action potential of the muscle cell, which is controlled by calcium in the muscle cells of the heart as well as the muscle cells of the vessels.
The action potential in the so-called striated muscle cells in the body, which can be tensed at will, such as the biceps, is not dependent on calcium. This explains why taking verapamil affects the muscle contraction of the heart muscle and the muscles of the vessels, but has no effect on the other muscles in the body. In certain diseases, the role of calcium can be exploited by blocking this channel and thus influencing the contraction of the heart or the wall tension of the vessels.
Verapamil is used in a number of cardiovascular diseases where the effect of blocked calcium channel is used. Thus, verapamil is used mainly for cardiac arrhythmia, high blood pressure and coronary heart disease. Verapamil belongs to the so-called class IV antiarrhythmics, which are supposed to improve cardiac arrhythmias by blocking the calcium channel.
It is important to note that, like all drugs used to treat cardiac arrhythmias, verapamil itself can cause cardiac arrhythmias when used, for example, in heart-healthy individuals. The effect on the wall tension of the vessels is used in the treatment of essential hypertension, i.e. high blood pressure. By dilating the vessels, blood pressure is reduced.
The same effect is used in the treatment of coronary heart disease. Verapamil is used to reduce the tension in the walls of all vessels, thus dilating them. This also applies to the coronary arteries, which are clogged in the clinical picture of coronary heart disease.
By taking verapamil, the lumen can be enlarged, thus significantly improving the oxygen supply to the heart. Like all drugs, verapamil is not without side effects, some of which are more common than others. Up to ten percent of people taking verapamil suffer from side effects such as headache, dizziness, ankle edema, flushing, or a noticeably slow heartbeat (bradycardia).
Rare side effects include the occurrence of a heart rhythm disorder or an allergic skin reaction. It is important that the full dose of verapamil should not be taken at the beginning of therapy. The vasodilator effect could then cause a massive drop in blood pressure.
This is prevented by slowly increasing the dose. Due to the breakdown of verapamil in the liver and the enzymes associated with it, interactions occur when taking verapamil and other drugs or foods. For this reason, before prescribing verapamil, the attending physician should be informed about the current drug intake.
Since the study evidence on the use of verapamil in pregnant women is very thin, it is not recommended to take it during pregnancy.This means that in the case of a pregnancy, other drugs can be used if their safety for the child and the mother has been sufficiently proven. In general, if you experience certain symptoms while taking verapamil that seem unusual, you should inform your doctor. The doctor may adjust the dose or recommend another medication for treatment.
