Beta-blockers are medicines that are used to treat a variety of conditions. Their full correct name is beta-adrenoceptor blocking medicines (or beta-adrenergic blocking agents), but they are commonly just called beta-blockers.

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Beta-blockers work by blocking the transmission of certain nerve impulses. The ends of some nerves release a chemical (neurotransmitter) called noradrenaline when the nerve is stimulated. This chemical then stimulates beta-adrenergic receptors.

These receptors are tiny structures which occur on cells in various parts of the body, including the heart, brain, and blood vessels. When these receptors are stimulated, they cause various effects. For example, nerve impulses to the heart can stimulate beta-adrenergic receptors on heart cells. This causes an increase in the force and rate of the heartbeat. This can cause a fast heartbeat and higher blood pressure.

The beta-adrenergic receptors are also stimulated by adrenaline (epinephrine), a hormone which circulates in the bloodstream. Adrenaline is made in the adrenal gland. The blood level of adrenaline can vary. For example, you may release a lot of adrenaline into the bloodstream when you are frightened or anxious which can cause an increase in your heart rate, and other effects.

The beta-blocker medicine 'sits' on beta-adrenergic receptors and stops (blocks) the receptor from being stimulated. So, for example, if beta-adrenergic receptors in the heart are blocked, the force and rate of the heartbeat are reduced.

There are several types of beta-blockers - these include:

Each type has one or more brand names.

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Because of their effect on the heart cells, beta-blockers may be used to:

Because beta-adrenergic receptors are found in other parts of the body, beta-blockers are also used for various other conditions. These include:

Most people who take beta-blockers have no side-effects, or only minor ones. However, because of their action in various parts of the body, some people have unwanted side-effects. The side-effects of beta-blockers include::

Some people with asthma are advised not to take a beta-blocker. If you have asthma or something similar, discuss this with your GP.

The above is not a full list of possible side-effects but mentions the main ones that may occur. Read the information leaflet that comes with your particular brand for a full list of possible side-effects and cautions.

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The length of treatment depends on why you are taking a beta-blocker. Some people only need to take beta-blockers for a few weeks, or months - for example, if you have an overactive thyroid. Some people need to take beta-blockers for the rest of their lives - for example, after a heart attack (myocardial infarction).

You cannot take a beta-blocker if you have certain conditions, including:

Further reading and references

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The information on this page is written and peer reviewed by qualified clinicians.

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