Beta blockers

What do beta blockers do?

Beta blockers are a group of medicines that slow your heart rate and lower your blood pressure, making it easier for your heart to pump blood. They are used to treat a variety of conditions related to your heart such as:

Beta blockers are also used for other conditions such as:
  • reduce tremors
  • reduce symptoms of anxiety such as fast heart rate
  • prevent migraine  headaches
  • glaucoma, where beta blocker eye drops reduce the pressure in your eye.  

Examples of beta blockers

There are several beta-blockers and each has its own characteristics. Your doctor will advise which one is best for you.

Precautions before taking beta blockers

Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care. It’s important that you tell your doctor or pharmacist before you start using beta blockers if you have:

  • asthma or COPD
  • diabetes
  • low blood pressure
  • very slow heart rate.

How to take beta blockers

When you first starting taking a beta blocker, your doctor will start you on a low dose then slowly increase it over the next few weeks. It can take a while for you to feel better — usually a few months.

Do not suddenly stop taking your beta blocker
Do not suddenly stop taking your beta blocker without talking to your doctor first. This can be dangerous and make you feel unwell. You may get the feeling of changes in your heart beat (fast, quick and irregular or forceful heartbeats), an increase in blood pressure and a return of chest pains. If you do need to stop taking a beta-blocker then your doctor may advise a gradual reduction in dose.

Possible side effects

When you first start taking a beta blocker or get your dose increased you may feel tired or have other side effects for a few days. These side effects usually slowly go away with time. 

Diabetes

If you have diabetes you need to take extra care to measure your blood glucose levels regularly.

  • Beta-blockers can cause an increase in blood glucose levels, especially when you first start taking them. This effect usually settles with time.
  • Beta-blockers may reduce the warning signs of a low blood sugar level (hypoglycaemia - often called a hypo). For example, you may not develop the sensation of rapid, irregular or forceful heartbeats (palpitations) or tremor, which tend to occur as the blood sugar is going too low. If you are concerned about this, talk to your doctor. Do not stop taking your beta-blocker without checking with your doctor first. Read more about hypoglycaemia.

Asthma

If you have asthma, taking a beta blocker may trigger your asthma symptoms or make them worse. Not everybody with asthma is sensitive to these medicines. If you are concerned about this, talk to your doctor. They may be able to prescribe a different medicine or increase the dose of your asthma preventer medication. Do not suddenly stop taking your beta blocker without talking to your doctor first. This can be dangerous and make you feel unwell. Read more about medicines that may trigger asthma symptoms

Other possible side effects

Side effects What should I do?

These are quite common when you first start taking a beta blocker, and usually go away with time.

  • cold hands and feet
  • rash or itching
  • dizziness, tiredness
  • constipation or diarrhoea
  • depression and low mood
  • nightmares or sleep problems
  • sexual problems
  • nausea 
  • Tell your doctor if they do not go away or are troublesome for you. 

If you get any of these symptoms: 

  • problems breathing such as chest tightness or wheezing 
  • swelling of the feet or legs
  • feel like fainting
  • chest pain
  • changes in heart rate (fast, slow or irregular)
Tell your doctor immediately or ring HealthLine 0800 611 116.

References

  1.  New Zealand Formulary
Credits: Sandra Ponen, pharmacist. Last reviewed: 21 Sep 2018