What are beta blockers?
Beta-blockers (also known as beta-adrenoceptor blocking agents) are medications used to treat several conditions, often by decreasing heart activity. They block the release of the hormones adrenaline and noradrenaline in certain parts of the body.
Noradrenaline is a chemical released by nerves when they're stimulated. The noradrenaline passes messages to other parts of the body, such as muscles, blood vessels and the heart.
When are they used?
Beta-blockers may be used to treat:
- (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)
- (high blood pressure)
Less commonly, beta-blockers are used to prevent
or treat:- anxiety conditions
- tremor
- (as eye drops)
There are several types of beta-blocker and each has its own characteristics. The type prescribed for you will depend on your condition but they're all equally effective.
Things to consider
There are several things to consider before taking beta-blockers.
Make sure your doctor is aware if you have a history of:
- or any lung disease
- heart disease
- kidney disease
- (especially in diabetics who have frequent episodes of low blood sugar)
- allergic reaction to any medication
Your doctor can tell you which medicine to use if you're pregnant or breastfeeding. It's important you don’t stop taking beta-blockers without your doctor's advice. In some cases, suddenly stopping the medicine may cause your condition to get worse.
If you want to check whether other medicines are safe to take with beta-blockers, ask your doctor or pharmacist, or read the medicine's patient information leaflet.
There may be side effects while taking beta-blockers, including the following:
- dizziness
- excessive tiredness
- blurred vision
- cold hands and feet
- slow heartbeat
- and nausea
Less common side effects include:
- sleep disturbance ()
- lack of sex drive ()
Missed or extra doses
If you forget to take a dose of beta-blockers, the general advice is described below.
- if it's less than 2 hours late, take the dose as soon as you remember and continue as normal
- if it is more than 2 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 2 doses closer together than normal, you may get more side effects
If you're 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, or accidentally take an extra dose of beta-blockers, contact your doctor or an emergency medical centre for advice.
Side-effects of beta blockers
It's more common to experience side effects while taking beta-blockers when you start taking a new medicine, or if your dose is increased.
Contact your doctor if the side effects are affecting your life or don't get better over time as your doctor may wish to review your dose or medication.
Common side effects of beta-blockers include:
- dizziness
- excessive tiredness
- blurred vision
- cold hands and feet
- slow heartbeat
- and nausea
Less common side effects include:
- sleep disturbance ()
- lack of sex drive ()
- in men, problems getting an erection ()
Driving while taking beta-blockers
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. Don't drive if you have these side effects.
How beta blockers works
Beta-blockers block the release of the hormones adrenaline and noradrenaline in certain parts of the body. They help reduce blood pressure by making the heart work more slowly and improve blood flow by helping blood vessels to open.
Beta-blockers take some workload off the heart. This means the heart doesn't have to work so hard pumping blood around the body.
This medicine is especially important for people with
(chest pain caused by restricted blood flow to the heart) or heart failure, or for those who've had a . It helps prevent attacks of angina and reduces your risk of having a further heart attack if you've 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 heart rate.
Beta-blockers are also commonly used to treat:
- (high blood pressure) – beta-blockers reduce blood pressure by slowing the heart rate and pumping force of the heart
- heart failure (where the heart does not pump blood around the body effectively)
- (irregular heartbeat)
Read more information about the
.Beta-blockers are sometimes used to prevent
or treat:- an
- conditions
- – eye drops can be used which relieve pressure inside the eyeball by reducing the production of aqueous humour (fluid inside the eyeball)
How beta blockers interact with other medicines
When 2 or more medicines are taken at the same time, the effects of one of the medicines can be altered by the other (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 your medicines are safe to take with beta-blockers, ask your doctor or pharmacist, or read the patient information leaflet that comes with your medicine.
Anti-arrhythmics
Anti-arrhythmics are medicines that control irregular heartbeat. There's 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
(hypotension) when taken with beta-blockers.Antipsychotics
Antipsychotics are medicines used to treat severe mental health problems. Some types of beta-blockers can increase the risk of arrhythmias when given to people taking antipsychotics.
Other medication
Some specific medicines known to interact with beta-blockers are listed below.
- clonidine is medicine used to treat (hypertension) and . 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 can cause heart block and a slow heart rate when taken with beta-blockers
- mefloquine can cause a slow heart rate when used with beta-blockers
- verapamil, nifedipine and nisoldipine can cause severe low blood pressure and heart failure when taken with beta-blockers
Missed or extra doses of beta blockers
Missed doses
If you forget to take a dose of beta-blockers, the general advice is as follows:
- if it's less than 2 hours late, take the dose as soon as you remember and continue as normal.
- if it's more than 2 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 2 doses closer together than normal, you may get more side effects
If you're 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.
Extra doses
If you accidentally take 1 or more extra doses of beta-blockers, contact your doctor.
Special considerations of beta blockers
Before taking beta-blockers, make sure your doctor is aware of any other conditions you have as they may not be suitable to use.
When to avoid them
You should normally avoid taking beta-blockers if you have:
- a history of 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 (partial or total blockage of an artery, usually one leading to a leg or arm)
Make sure your doctor is aware if you have a history of allergic reaction to any medication.
Using them with caution
Beta-blockers should be used with caution if you have:
- (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 (hypotension)
- 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 doctor can tell you which medicine to use if you're pregnant or breastfeeding.
Stopping beta-blocker treatment
Beta-blocker treatment must not be stopped suddenly without your doctor's advice. Suddenly stopping the medicine may cause your condition to get worse, for example, if you are taking it to treat
or following a .