Beta-blockers
Introduction
Beta-blockers (also known as beta-adrenoceptor blocking agents) are commonly used to treat:
- hypertension (high blood pressure)
- angina (chest pain caused by restricted blood flow to the heart)
- heart failure (where the heart does not pump blood around the body effectively)
- atrial fibrillation (irregular heartbeat)
- heart attack
See Uses of beta-blockers for more information.
Less commonly, beta-blockers are used to:
- prevent migraine
- treat overactive thyroid
- treat anxiety conditions
- treat tremor
- treat glaucoma
There are several types of beta-blocker and each has its own characteristics. The type prescribed for you will depend on your condition. They are all equally effective.
How they work
Beta-blockers work by blocking the release of noradrenaline in certain parts of the body.
Noradrenaline is a chemical released by nerves when they are stimulated. The noradrenaline passes messages to other parts of the body, such as the muscles, blood vessels and heart.
This means that beta-blockers can, for example, decrease the activity of your heart (see Uses of beta-blockers for more information).
Names
Examples of beta-blockers are:
- acebutolol (Sectral)
- atenolol (Tenormin)
- bisoprolol (Cardicor, Emcor)
- carvedilol (Eucardic)
- celiprolol (Celectol)
- labetalol (Trandate)
- metoprolol (Betaloc, Lopresor)
- nadolol (Corgard)
- nebivolol (Nebilet)
- pindolol (Visken)
- propranolol (Inderal)
- sotalol (Beta-Cardone, Sotacor)
- timolol (Betim)
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Uses
Uses of beta-blockers
Beta-blockers block the release of the chemical noradrenaline in certain parts of the body.
Heart problems
Beta-blockers take some of the workload off the heart. This means that the heart does not have to work so hard at pumping blood around the body.
This medicine is especially important for people with angina or heart failure, or for those who have had a heart attack. It helps prevent attacks of angina and reduce your risk of having a further heart attack if you have already had one.
Beta-blockers control irregular heartbeats by blocking the electrical nerve impulses that stimulate the heart. This decreases the activity of the heart and can slow the heart rate.
High blood pressure
In the treatment of hypertension (high blood pressure), beta-blockers reduce blood pressure by slowing the heart rate and pumping force of the heart.
Glaucoma
Beta-blocker eye drops can be used for glaucoma. They relieve the pressure inside the eyeball by reducing the production of aqueous humour (fluid inside the eyeball).
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Considerations
Special considerations
When to avoid them
You should normally avoid taking beta-blockers if you have:
- a history of asthma or narrowing of the airways (some beta-blockers may be occasionally used in people with these conditions, but only under the supervision of a doctor)
- heart block (where the heart beats irregularly or more slowly than usual)
- worsening, unstable heart failure (although beta-blockers can be used to treat stable heart failure)
- severe peripheral arterial disease (partial or total blockage of an artery, usually one leading to a leg or arm)
Using them with caution
Beta-blockers should be used with caution if you have:
- diabetes (especially in diabetics who have frequent episodes of low blood sugar)
- myasthenia gravis (a condition that causes muscle weakness)
- slow heart rate
- low blood pressure
- phaeochromocytoma (high blood pressure caused by a tumour of the adrenal gland)
- metabolic acidosis (high levels of acid in the blood)
- Prinzmetal's angina (type of chest pain)
Pregnancy and breastfeeding
Some beta-blockers may be suitable for use in some stages of pregnancy and during breastfeeding.
Your GP can tell you which medicine to use if you are pregnant or breastfeeding.
Stopping beta-blocker treatment
Beta-blocker treatment must not be stopped suddenly without your GP's advice. Suddenly stopping the medicine may cause your condition to get worse, for example if you are taking it to treat angina or following a heart attack.
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Side effects
Common adverse effects
Common side effects of beta-blockers include:
- excessive tiredness
- cold hands and feet
- slow heartbeat
- diarrhoea and nausea
Less common side effects include:
- sleep disturbances
- nightmares
- impotence
Ability to drive
Beta-blockers are unlikely to affect your ability to drive safely. However, some people may sometimes feel dizzy or mentally or physically tired when taking beta-blockers. Do not drive if you have these side effects.
Reporting side effects
The Yellow Card Scheme allows you to report suspected side effects from any type of medicine that you are taking. It is run by a medicines safety watchdog called the Medicines and Healthcare products Regulatory Agency (MHRA). See the Yellow Card Scheme website for more information.
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Interactions other medicines
Interactions with other medicines
When two or more medicines are taken at the same time, the effects of one of the medicines can be altered by the other. This is known as a drug-drug interaction.
Beta-blockers (including beta-blocker eye drops) can interact with other medicines.
Some of the more common interactions are listed below. However, this is not a complete list.
If you want to check that your medicines are safe to take with beta-blockers, you can ask your GP or pharmacist, or read the patient information leaflet that comes with your medicine.
Anti-arrhythmics
Anti-arrhythmics are medicines that control irregular heartbeats. There is a risk of myocardial depression (impaired function of the heart) and arrhythmias (irregular heartbeats) when beta-blockers are taken with these medicines.
Antihypertensives
Antihypertensives (medicines given to lower blood pressure) can cause low blood pressure when taken with beta-blockers.
Antipsychotics
Antipsychotics are medicines used to treat severe mental health problems. Some types of beta-blockers (for example, sotalol) can increase the risk of arrhythmias when given to people taking antipsychotics.
Clonidine
Clonidine is medicine used to treat high blood pressure and migraine. Rebound hypertension (a sharp and sudden rise in blood pressure) can occur if you stop taking clonidine while taking a beta-blocker.
Diltiazem and digoxin
Diltiazem and digoxin can cause heart block and a slow heart rate when taken with beta-blockers.
Mefloquine
Mefloquine can cause a slow heart rate when used with beta-blockers.
Verapamil, nifedipine and nisoldipine
These medicines can cause severe low blood pressure and heart failure when taken with beta-blockers.
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Interactions - food or alcohol
Interactions with food and alcohol
Alcohol can cause low blood pressure in people taking beta-blockers.
However, there are no known interactions between beta-blockers and specific foods.
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Missed and extra doses
Missed doses
If you forget to take a dose of beta-blockers, the general advice is as follows:
- If it is less than two hours late, take the dose as soon as you remember and continue as normal.
- If it is more than two hours late, take the dose as soon as you remember, as long as the next dose is not due within a few hours, then continue as normal. If you take two doses closer together than normal, you may get more side effects.
If you are not sure what to do about your dose, check the patient information leaflet that comes with your medicine. This should give you advice about what to do.
If you need further advice, contact your GP or pharmacist or call NHS Direct Wales on 0845 46 47.
Extra doses
If you accidentally take an extra dose or extra doses of beta-blockers, contact your GP or call NHS Direct Wales on 0845 46 47.
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