Sounds like 'a-ten-o-lol'

Atenolol is used to treat high blood pressure and prevent chest pain (angina). Find out how to take it safely and possible side effects.

What is atenolol?

Atenolol is used mainly to lower high blood pressure. It can also be used to prevent chest pain (angina) or to treat an irregular heartbeat (arrhythmia). Atenolol works by slowing down your heart rate, making it easier for your heart to pump blood around your body. It belongs to a group of medicines called beta blockers. 


In Aotearoa New Zealand, atenolol comes as tablets (50 mg and 100 mg). 

  • The usual dose of atenolol is 50 or 100 milligrams (mg) daily. The dose will be different for different people. Some people may need lower doses.
  • Your doctor will usually start you on a low dose and increase the dose depending on your response. This allows your body to get used to the medicine and reduces your risk of getting side effects.
  • Always take your atenolol exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much atenolol to take, how often to take it, and any special instructions.

How to take atenolol

  • Timing: Take atenolol at the same time each day. If you're taking atenolol twice a day, try to have 1 dose in the morning and 1 dose in the evening. It's a good idea to leave 10 to 12 hours between doses if you can. You can take atenolol with or without food. Swallow your tablet with a glass of water.
  • Missed dose: If you forget to take your tablet, take it as soon as you remember that day. But if it is nearly time for your next tablet, just take the next tablet at the right time. Do not take double the dose.
  • Keep taking atenolol regularly. Treatment with atenolol is usually long term. Don't stop taking atenolol suddenly; talk to your doctor or pharmacist before stopping.

Things to consider while you are taking atenolol

  • Avoid alcohol while you are taking atenolol, especially when you first start treatment. Alcohol can increase your risk of side effects such as dizziness.
  • Atenolol can interact with other medicines. Tell your doctor or pharmacist about all medicines you are taking including over the counter medicines, herbal and complementary medicines or recreational drugs.

If you have diabetes

  • If you have diabetes, atenolol may cause changes in your blood glucose level. 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. Don't stop taking atenolol without checking with your doctor first. Read more about hypoglycaemia.

If you have 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 atenolol.
  • 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 atenolol without talking to your doctor first. This can be dangerous and make you feel unwell. Read more about medicines that may trigger asthma symptoms.

Possible side effects

Side effects What should I do?
  • Tiredness
  • Headache
  • Problems falling asleep or nightmares
  • Nausea (feeling sick) or vomiting
  • Sexual problems
  • These things are quite common when you first start taking atenolol and usually go away with time.
  • Tell your doctor if these side effects bother you.
  • Dizziness
  • Feeling faint when you stand up
  • This is common when you first start taking atenolol.
  • Avoid alcohol.
  • Be careful when getting up from either lying down or sitting to avoid falls.
  • Changes in your heartbeat (either feeling like it is too fast or irregular)
  • Tell your doctor.
  • Cold hands and feet
  • Dry eyes
  • Sleep problems
  • Nightmares
  • Tell your doctor if they bother you.
  • Low mood
  • 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. 
For more information on side effects, see the Medsafe consumer information leaflet Mylan Atenolol.

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.

Learn more

Medsafe Consumer Information Sheets: Mylan Atenolol 
New Zealand Formulary Patient Information: Atenolol


  1. Atenolol NZ Formulary
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist Last reviewed: 01 Dec 2022