How does Esmolol work? - MedicineHow

How does Esmolol work?

How does Esmolol work

Esmolol is a short-acting drug that works by blocking beta receptors that are found in the heart. This causes the heart muscles to contract more slowly, which is useful in the treatment of atrial fibrillation when your heart is beating out of rhythm.

Brand Names and Doses

Brand Dose IconEsmolol is the generic name of the drug – the active ingredient in the medication. Brevibloc is the brand name, which is the name given by the manufacturing company.

It is only available as an injection for emergency use in a hospital environment. This is because it is very short-acting and is excreted from the body very quickly. If it was an oral medication, you would need to take a tablet every hour or so to keep it working continuously!

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What is it used for?

Uses IconEsmolol is used to manage atrial fibrillation or atrial flutter, which is essentially the heartbeat that is slightly out of rhythm.

It can help in the acute control of ventricular rate. it is often used for this reason after a surgical procedure, for example. Additionally, it can be beneficial for sinus tachycardia.

How does Esmolol work?

How it works IconEsmolol works by blocking certain receptors found in your body, called beta1 receptors. These receptors are mostly found in the heart and are involved in the contraction of the heart muscles, which pushes the blood out of the heart and around the body.

When you take a beta blocker drug like esmolol, these receptors can’t function as well as they usually do. As a result, the heart muscle contracts less often and less forcefully, which means that both your blood pressure and heart rate will decrease.

This is very beneficial to control the rate of the heart, particularly when it is beating too fast.

Side Effects

Side Effects IconThe most common side effect of esmolol occurs when the dose is too high and you end up with low blood pressure (hypotension). This may make you feel light-headed, dizzy or tired. Other side effects may include:

  • Chest pain
  • Peripheral ischaemia
  • Nausea, vomiting or constipation
  • Confusion
  • Agitation

Esmolol has a very short action and is quickly excreted from your body, which is a great thing to minimize side effects. Any adverse effects will typically last less than 30 minutes because your body is so efficient at removing it from the body.


Cautions IconThere are some cases when esmolol can do more harm than good and is contraindicated. You should not take esmolol if you have:

  • Second or third-degree heart block (without a pacemaker)
  • Sinus bradycardia (without a pacemaker)
  • Cardiogenic shock

It can also have a negative effect in some other conditions although it is still sometimes used. For example, it has the potential to worsen:

  • Peripheral circulation – problematic in peripheral vascular disease and Raynaud’s phenomenon
  • Asthma, as it may constrict the airways due to other beta blockers in this area
  • Hypotension, as it works by lowering the blood pressure
  • Heart failure

Additionally, it can also mask signs of side effects associated with hypoglycemia in Diabetes, such as racing heart and tremor.

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Pregnancy and Breastfeeding

Pregnancy IconEsmolol is occasionally used for women who are pregnant, although it depends on the specific circumstances. It is category C in pregnancy, but is short-acting and may be acceptable for a short duration.

It can be used with caution in breastfeeding women and it is important to monitor for signs in the infant.

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How does Esmolol work?

About the author


Yolanda is a passionate medical writer who loves to help people understand how health and different treatments work. After graduating in Pharmacy in Australia, she moved to Italy to study the Mediterranean way of life and continue learning about health and medicine.

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