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Beta-blockers are medicines that are sometimes used to treat people with high blood pressure. Most of these medicines have names that end in “olol”.
All about beta-blockers
How do beta-blockers work?
Beta-blockers lower your blood pressure by blocking the effect of hormones called adrenaline and noradrenaline. By blocking these hormones, beta-blockers slow down your heart rate and reduce the force at which blood is pumped round your body.
Beta-blockers also block your kidneys from producing a hormone called angiotensin II. Reducing the amount of angiotensin in your body allows your blood vessels to relax and widen, making it easier for blood to flow through.
Who might be given a beta-blocker?
Beta-blockers are not usually used as a first choice medicine for high blood pressure. They are usually given to people who cannot tolerate other blood pressure medicines, or whose blood pressure is not being lowered enough by other medicines.
If you have previously had a heart attack, have angina, heart failure or an irregular heart beat, you may be given a beta-blocker. They may help to prevent attacks of angina and reduce your risk of having a further heart attack.
Women who have high blood pressure but who might become pregnant may be given a beta-blocker.
Who would not be given a beta-blocker?
If you have asthma, or lung problems such as chronic obstructive pulmonary disease (COPD), you would not usually be given a beta-blocker. This is because they can narrow your airways which could trigger or worsen an asthma attack. If you do need to take a beta-blocker, you will need to be monitored closely.
Other people who may not be given a beta-blocker include people with a second or third degree heart block, people with worsening or unstable heart failure, or anyone with severe peripheral arterial disease.
Some people who are given a beta-blocker will require close monitoring. These include people who have a low heart rate, people with diabetes or a phaeochromocytoma (tumour of the adrenal gland), or people who have high levels of acid in the blood (metabolic acidosis) or a type of angina known as Prinzmetal’s angina.
Your doctor will not give you a beta-blocker if they feel that it could affect other conditions that you have or other medicines that you are taking.
Beta-blockers used in the UK
|Medicine name||Brand names|
|Atenolol||Atenolol, Atenolol BP, Beta-Adalat, Co-Tenidone, Co-Tenidone BP, Tenif, Tenoret, Tenoretic, Tenormin, Tenormi LS|
|Bisoprolol||Cardicor, Emcore, Monocor|
|Metoprolol||Betaloc SA, Co-Betaloc, Lopresor, Lopresor SR, Metaprolol|
|Oxprenolol||Slow Trasicor, Trasicor|
|Propranolol||Inderal LA, Propranolol|
Do beta-blockers have side-effects?
Most people will have no side-effects from their blood pressure medicines. They usually only happen when you start to take a new medicine, or a higher dose of your medicine. If you do experience a side-effect it may lessen over time as your body gets used to the medicine. If not, your doctor may change your dosage or your medicine if they feel it is appropriate.
Possible side-effects of beta-blockers include:
- tiredness, dizziness and lethargy, or sleep problems (including vivid dreams)
- low heart beat rate
- cold hands and feet
- diarrhoea and nausea.
And, less commonly:
- problems with erections in men
When to contact your doctor
If your breathing is affected, or you start to develop asthma when you take your beta-blocker, you should contact your doctor immediately.
Other things to be aware of when taking beta-blockers
If you are taking a beta-blocker with another type of blood pressure medicine, called a thiazide diuretic, you can have an increased long-term risk of developing diabetes. If you already have diabetes and need to take a beta-blocker, you should be aware that they can dull the warning signs of a low blood sugar level.
You should not stop taking your beta-blocker medicine suddenly – unless your doctor has specifically told you to do so. If you need to be switched to a different medicine, your doctor would normally reduce your dosage gradually. This is because stopping a beta-blocker suddenly could trigger palpitations, an attack of chest pain (angina) or a rise in your blood pressure.
Beta-blockers can cause dizziness in some people; therefore if you operate heavy machinery, or drive for a living you should be aware of this before you start taking them. If you experience any dizziness you should tell your doctor (and your employer) immediately.
If you are taking a beta-blocker you should avoid alcohol. This is because it can enhance the blood pressure-lowering effects of your medicine and could lower your blood pressure too much. Similarly, if you are about to have surgery that requires an anaesthetic you may be asked to come off of your beta-blocker for a while, for the same reason.
Check with your doctor or pharmacist before taking any other medicines in combination with your beta-blocker – this includes over-the-counter treatments.
As with other blood pressure lowering medicines, once you start taking a beta-blocker, be prepared to stay on it for the long term. Some people stop taking their blood pressure medicines when they think their blood pressure is under control, but doing this can put your health at risk.
If you have any concerns about your medicines, speak to your doctor or pharmacist.
Published May 2009