Beta-blockers

Beta-blockers are a type of medication that is sometimes used to treat high blood pressure. Beta-blockers used to be commonly prescribed for people with high blood pressure, but recent guidelines state that they should not normally be used as a first-choice treatment.

Beta-blockers block the action of the hormone noradrenaline on the body. Noradrenaline controls how wide or narrow your blood vessels are, and also makes your heart beat faster. This can help your body get ready for action, but it can also raise your blood pressure. Beta-blockers reduce the effects of noradrenaline, causing your heart to beat more slowly and reducing the force with which your blood is pushed round your body. This lowers your blood pressure.

Beta-blockers also reduce the amount of the hormone angiotensin-II released by your body. Angiotensin-II causes your arteries to narrow, and your body to retain water, both of which raise your blood pressure.

Who should take beta-blockers?

Beta-blockers are useful for people who cannot take an ACE inhibitor or an angiotension receptor blocker. They may also be used by younger women who may become pregnant (but not to women who are already pregnant).

Beta-blockers are often used if you also have angina, have had a previous heart attack, or are being treated for heart failure. This is because they help to lower the strain on your heart as well as lowering your blood pressure. Beta-blockers are also helpful in correcting abnormal heart beats.

Who should not take beta-blockers?

If you operate heavy machinery or drive for a living, you need to be careful when taking a beta-blocker as they can occasionally cause dizziness or fatigue and may impair your ability to do your job safely.

If you have peripheral artery disease or pain in your calves when walking, beta-blockers may make this worse.

Because beta-blockers slow the heart rate, this can be a problem if you already have a low heart rate.

Beta-blockers can also act on your lungs, narrowing the airways. This can cause asthma or make an attack much worse.

What are the most common side-effects of beta-blockers?

Beta-blockers have subtle side-effects that are not serious, but may affect your enjoyment of life. These include:

• Tiredness and lethargy: slowing the heart beat means that your body may not be receiving as much oxygen and nutrients as it used to, reducing your energy levels.
• Sleep problems: taking high doses of beta-blockers can sometimes cause sleep problems and nightmares.
• Cold hands and feet: in winter, you may experience cold hands and feet because your heart is not pumping the blood to your extremities with the same force as before.

If you take a beta-blocker with a  thiazide diuretic, you have an increased risk of developing diabetes. If you are taking this combination of medicines, together speak to your doctor at your next appointment about whether other medicines may be more appropriate for you or not.

If you develop side-effects from your medications, your doctor may be able to help by lowering your dose, or by changing your medicine. Do not stop taking any medication without first speaking to your doctor.

Other things you need to know

If you are taking a beta-blocker, you should avoid using non-steroidal anti-inflammatory drugs (NSAIDs) because they can lower the effectiveness of the beta-blocker. You should also avoid using over-the-counter cold and flu remedies while taking beta-blockers.

Be careful about how much alcohol you are drinking too, because this can enhance your beta-blocker’s blood pressure lowering effect and may lower your blood pressure too far.

You should not stop taking beta-blockers suddenly, unless your doctor has specifically told you to do so. If you do stop suddenly, your symptoms could get much worse and you may even damage your heart. Normally your doctor will slowly reduce your dose before switching you to another tablet.

Also, if you are going to have surgery that will require an anaesthetic, you may be asked to come off your beta-blockers for a while. This is because the anaesthetic may enhance your tablet’s blood pressure lowering effect and lower your blood pressure too much.

Types of beta-blocker

Most medicines have two names – the generic name (which is the name of the medicine itself) and the brand name (which is the name the medicine is sold under). This means different companies may make and sell the same medicine, but they may sell it with different brand names. The table below lists some beta-blocker medicines currently used in the UK: