The Uses and Side Effects of Verapamil

What are the different uses and side effects of verapamil? Although this drug is considered a cardiovascular medicine, it also has other applications, such as treating mania and preventing migraines.
The Uses and Side Effects of Verapamil

Last update: 19 January, 2020

Verapamil is a drug that can be administered both orally and intravenously, depending on the patient’s needs. This medication can be used to treat angina, hypertension, and arrhythmias. Keep reading to learn more about the uses and side effects of verapamil.

About Verapamil

Verapamil belongs to the family of class IV antiarrhythmics. It’s more effective than digoxin, the cardiotonic par excellence. for controlling atrial fibrillation.

Although verapamil is widely considered a cardiovascular drug, there are other applications. For example, it can also be used for the treatment of mania and the prevention of migraines.

There are different forms of this drug on the market that doctors can prescribe depending on the patient’s condition. For the treatment of angina, for example, doctors can prescribe extended-release tablets. On the other hand,  ophthalmic drops are helpful for the treatment of ocular hypertension and/or glaucoma.

What are arrhythmias?

Cardiac arrhythmias side effects of verapamil.

An arrhythmia is an anomaly in the heartbeat. In other words, the heart rate may decrease or increase. In the first case, this type of arrhythmia is called bradycardia and in the second case, tachycardia. When this occurs, it can affect the formation of the cardiac impulse. As a consequence, alterations in conduction can occur. This is called “reentry” and is one of the most common arrhythmias in the general population.

On the other hand, it’s worth mentioning that arrhythmias are usually harmless. However, some may endanger the patient’s life, so it’s very important to keep them under control.

There are four main types of arrhythmias:

  1. Extrasystoles
  2. Supraventricular arrhythmias.
  3. Ventricular arrhythmias
  4. Bradyarrhythmias

What about angina?

This condition, like myocardial infarction (heart attack), is a type of ischemic heart disease. This disease stems from the deterioration and obstruction of the arteries in the heart.

This situation is known as arteriosclerosis and is caused by the accumulation of cholesterol plaques, lipids and inflammatory cells in the walls of these arteries. As a consequence, the heart does not receive enough blood to function properly.

Angina pectoris (ischemic chest pain) appears progressively over time, as a result of the deterioration of the arteries in the heart. Furthermore, there are two different classifications of this condition:

  • Stable angina pectoris: pain appears when you exercise and can spread to other areas of the body.
  • Unstable angina pectoris: the pain appears at rest and is more lasting than in the case of stable angina pectoris.

How does verapamil work?

Heart arrhythmias side effects of verapamil.

This medicine owes its effectiveness against the aforementioned diseases to its ability to block voltage-dependent calcium channels. Additionally, it acts on the entry of extracellular calcium through the membranes of heart muscle cells. Moreover, it doesn’t alter the calcium levels in the plasma.

To do this, verapamil attaches to the slow calcium channels, modifying its structure. As a result, they cannot move calcium from the plasma into the myocardial cells.

Also, this medication interferes with the release of intracellular calcium that is stored in the sarcoplasmic reticulum, a cellular structure. By reducing the levels of calcium inside the cell, the heart muscle dilates, affecting the contractile mechanism. The same goes for the smooth muscle of the blood vessels.

In this way, this process reduces peripheral resistance and, therefore, post-load. These mechanisms explain the beneficial effects of verapamil for patients suffering from angina and hypertension.

Side effects of verapamil

Cardiac arrhythmia pain side effects of verapamil.

The most serious side effects of verapamil include:

  • Sinus bradycardia
  • Sinus tachycardia reflex
  • Atrioventricular block of a different grade; you may need treatment with another drug
  • Hypotension

It’s important to know that the side effects of verapamil are more frequent with intravenous administration than oral administration. In addition to these serious effects, due to its vasodilator action, a patient may also develop other unwanted effects, such as:

  • Dizziness
  • Hot flashes
  • Fatigue
  • Headache
  • Vomiting
  • Abdominal pain

Finally, although it is very rare, some patients have developed hypersensitivity reactions.


Verapamil is a drug that is helpful mainly for the treatment of angina pectoris, hypertension, and various types of arrhythmias.

However, it has quite dangerous side effects, so it’s important to be especially careful when receiving treatment with this medication. Finally, you should always follow your doctor’s recommendations and ask about any abnormal discomfort or questions you have.

It might interest you...
Hypertension and Kidney Failure
Step To HealthRead it in Step To Health
Hypertension and Kidney Failure

The link between hypertension and kidney failure is undeniable. Learn how you can treat this condition and protect your kidneys in this article.

  • Dr. J. Manuel Guía Torrent, D. F. E. C. (2006). Tratamiento Médico De Las Taquicardias Supraventriculares. Protocolos Diagnósticos y Terapéuticos En Cardiología Pediátrica.
  • Machado-Alba, J. E., Giraldo-Giraldo, C., & Machado-Duque, M. E. (2015). Calidad de la prescripción de verapamilo de liberación convencional en pacientes con hipertensión arterial. Revista de Calidad Asistencial.
  • Morales, M. G., Guerrero, S. G., García, G. R., Villalobos, S. J., Camarena, A. G., Aguirre, S. J., & Martínez, S. J. (2005). Intoxicación grave con verapamilo. Archivos de Cardiologia de Mexico.