Beta blockers

Beta-blockers are a group of medicines that are used to treat a variety of conditions related to your heart.

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:

  • reducing tremors
  • reducing symptoms of anxiety such as fast heart rate
  • preventing migraine  headaches
  • glaucoma, as beta-blocker eye drops to reduce the pressure in your eye.  

The following animation describes how beta-blockers work in the body (British Heart Foundation)

Examples of beta-blockers

There are several beta-blockers and each is a bit different. Your doctor will advise which one is best for you.

Examples of beta-blockers

Precautions before taking beta-blockers

  • Do you have asthma or other breathing problems such as COPD (chronic obstructive pulmonary disease)? 
  • Do you have diabetes?
  • Do you have low blood pressure?
  • Do you have very slow heart rate?
  • Are pregnant or breastfeeding?

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

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 a 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 heartbeat (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 slow reduction in dose.

What are the side effects of beta blockers?

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. 


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 have the feeling of fast, irregular or strong heartbeats (palpitations) or tremor, which can occur when your blood glucose is going too low. If you are worried about this, talk to your doctor. Do not stop taking your beta-blocker without checking with your doctor first. Read more about hypoglycaemia.


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 worried 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
  • 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.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


  1. Beta-adrenoceptor blocking drugs New Zealand Formulary

Additional resources for healthcare professionals

Beta-blockers are no longer first line for simple hypertension Goodfellow Unit, NZ
Guide for initiation and up-titration of beta-blockers for patients with heart failure SafeRx, NZ, 2017

Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 29 Sep 2018