Sounds like 'met-oh-proe-lol'

Metoprolol has many uses such as after a heart attack (to prevent heart damage), heart failure, high blood pressure and irregular heart beat. Find out how to take it safely and possible side effects. Metoprolol is also called Betaloc CR.

Type of medicine Also called
  • Belongs to a group of medicines called beta-blockers
  • Betaloc CR®
  • Lopressor®
  • Slow Lopressor®
  • Myloc CR®

What is metoprolol?

Metoprolol is used to treat many conditions such as after a heart attack (to prevent heart damage), heart failure, high blood pressure (hypertension), and irregular heart beat. It belongs to a group of medicines called beta-blockers. Beta-blockers work by blocking some natural chemicals in the body, to slow the heart rate and lower blood pressure. Metoprolol is also used to prevent migraine headaches.  In New Zealand metoprolol comes as tablets.  


In Aotearoa New Zealand metoprolol is available in 2 forms - an immediate release tablet and a controlled release tablet.

  • Check with your pharmacist which form you are taking.
  • The dose of metoprolol will be different for different people.
  • Always take your metoprolol exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much metoprolol to take, how often to take it, and any special instructions. 
  • If you are not sure how much to take, ask your doctor, nurse or pharmacist.
  • Check with your pharmacist if your tablets are different to what you expect.

How to take metoprolol

  • If you are prescribed the immediate release tablet:
    • take these as you have been prescribed (usually 2 or 3 times a day)
    • take your doses at the same times each day.
  • If you are prescribed the controlled release tablet (usually has CR after the name):
    • take these once a day.
    • swallow the tablets whole, with a glass of water – do not crush or chew them.
  • You can take metoprolol with or without food.
  • Limit or avoid drinking alcohol while you are taking metoprolol.
  • If you forget your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Do not stop taking metoprolol suddenly; speak to your doctor or nurse before stopping.

Precautions before taking metoprolol

  • Do you have asthma?
  • Do you have diabetes?
  • Do you have problems with your kidneys?
  • Do you play a professional sport?
  • Are you pregnant or breastfeeding?
  • Have you ever had an allergic reaction to a medicine?
  • Are you are taking or using any other medicines? This includes any medicines you are using which are available to buy from a pharmacy, supermarket or natural health store without a prescription.

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

What are the side effects of metoprolol?

Like all medicines, metoprolol can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.


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 and this is rare with metoprolol. 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 side effects

Side effects What should I do?
  • Tiredness
  • Headache
  • Nausea (feeling sick) or vomiting
  • Problems sleeping
  • These are quite common when you first start taking metoprolol, and usually go away with time.
  • Tell your doctor if troublesome.
  • Dizziness
  • Feeling faint when you stand up
  • This is common when you first start taking metoprolol.
  • Be careful when getting up from either lying down or sitting to avoid falls.
  • Cold hands and feet
  • Tell your doctor if troublesome.
  • Depression and low mood
  • Sexual problems
  • Tell your doctor
  • Problems with breathing such as chest tightness, or wheezing or swelling of the ankles or feet.
  • 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


  • Check with a pharmacist before taking over the counter medicines such as:
    • Cold or flu tablets containing phenylephrine (e.g. Sudafed PE), or diphenhydramine (e.g. Benadryl Original)
    • Anti-inflammatories such as diclofenac (e.g. Voltaren Rapid), ibuprofen (e.g. Nurofen), mefenamic acid (e.g. Ponstan), naproxen (e.g. Naprogesic)
  • Metoprolol may interact with other medications and herbal supplements, so check with your doctor or pharmacist before starting metoprolol or before starting any new medicines.

Learn more

The following links have more information on metoprolol.

Metoprolol (Māori) New Zealand Formulary Patient Information

Medsafe Consumer Information Sheets

Metoprolol leaflet Institute for Innovation and Improvement & Waitematā DHB, NZ


  1. Metoprolol succinate New Zealand Formulary
  2. Metoprolol tartrate New Zealand Formulary

Additional resources for healthcare professionals

AFT – metoprolol Medsafe, NZ
Managing patients with heart failure in primary care BPAC, NZ, 2013
Hypertension in adults – the silent killer BPAC, NZ, 2013
Beta blocker titration SafeRx, Waitematā DHB, NZ, 2013
Medication alert – metoprolol HQSC, NZ, 2014

Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 30 Sep 2018