Atenolol - a beta-blocker (Tenormin)

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Atenolol belongs to the group of medicines known as beta-blockers. You are likely to have been prescribed it because you have high blood pressure, or angina chest pain, or a fast uneven heartbeat.

Treatment is usually long-term. Continue to take your doses regularly.

The most common side-effects are feeling tired, cold hands and feet, a slow heartbeat, and stomach upset. These are usually mild.
Type of medicineA beta-adrenoceptor blocking medicine (often referred to as a beta-blocker)
Used forHigh blood pressure; arrhythmias; angina; to protect the heart after a heart attack
Also calledTenormin®
Combination brands: Tenoret® and Tenoretic® (atenolol with chlortalidone), Beta-Adalat® and Tenif® (atenolol with nifedipine)
Available asTablets, and oral liquid medicine

Atenolol belongs to the group of medicines referred to as beta-blockers. It is a medicine which works on the heart and blood vessels. It does this by blocking tiny areas (called beta-adrenergic receptors) where messages sent by some nerves are received by your heart and blood vessels. As a result, your heart beats more slowly and with less force. The pressure of blood within your blood vessels is reduced and it is easier for your heart to pump blood around your body.

These actions are of benefit if you have high blood pressure (hypertension), or to prevent abnormally fast heart rhythms if you have arrhythmias. Because your heart is using less energy, it also helps to reduce chest pain if you have angina.

Atenolol is also available in combination with other medicines used to treat high blood pressure and angina. Combination brands of atenolol with a 'water tablet' (diuretic) called chlortalidone are Tenoret® and Tenoretic® (this combination also goes by the name co-tenidone). Combination brands of atenolol with the calcium-channel blocker nifedipine, are Beta-Adalat® and Tenif®.

Atenolol can also be prescribed to help prevent migraine. The leaflet does not contain information about this use of atenolol. If you have been given it for this reason, please ask your doctor if you have any questions about your treatment. 

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking atenolol it is important that your doctor knows:

  • If you are pregnant or breast-feeding.
  • If you have asthma or any other breathing disorder.
  • If you have any problems with the way your kidneys work.
  • If you have low blood pressure or poor circulation.
  • If you have sugar diabetes (diabetes mellitus).
  • If you have a skin problem called psoriasis.
  • If you have a condition causing muscle weakness, called myasthenia gravis.
  • If you have been told you have a slow heartbeat or heart block (a slow and irregular heartbeat).
  • If you have been told you have chest pain caused by spasms of your heart's blood vessels, called Prinzmetal's angina.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine, or if you have ever had any other serious allergic reaction.
  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about atenolol and will provide you with a full list of the side-effects which you could experience from taking it.
  • Take atenolol exactly as your doctor tells you to. It is usually taken once daily, in the morning. Some people taking it for angina may be prescribed two doses a day. Your doctor will tell you which dose is right for you, and the directions for taking it will also be printed on the label of the pack to remind you about what the doctor said.
  • Atenolol tablets are available in three different strengths - 25 mg, 50 mg and 100 mg. Each time you collect a fresh supply of tablets, it's a good idea to check the strength on the packet to make sure they are the strength you are expecting. If you have any questions, please ask your pharmacist to advise you.
  • You can take atenolol either with or without food, but try to take your doses at the same time of day each day as this will help you to remember to take it regularly. The tablets are best swallowed with a drink of water.
  • If you forget to take a dose, take it as soon as you remember (unless it is nearly time for your next dose, in which case leave out the missed dose and take the next dose as normal). Do not take two doses together to make up for a forgotten dose.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • Your doctor is likely to give you dietary and lifestyle advice about eating a healthy diet, not smoking, and taking regular exercise. If so, it is important that you follow the advice you are given.
  • If you drink alcohol, ask your doctor for advice about taking atenolol and alcohol. Atenolol will worsen the effects of alcohol, which will make you feel dizzy.
  • If you buy any medicines, check with a pharmacist that they are suitable for you to take with atenolol. Some medicines may not be (including some anti-inflammatory painkillers, and cold or flu remedies).
  • If you are due to have an operation or dental treatment, it is important to tell the person carrying out the treatment that you are taking a beta-blocker. This is particularly important if you are likely to be given an anaesthetic.
  • If you have diabetes, atenolol can block the symptoms of low blood sugar. Your doctor will advise you about this.
  • Treatment with atenolol is usually long-term. Continue to take the tablets unless your doctor tells you to stop. Stopping treatment suddenly can cause problems in some people, so your doctor may want you to reduce your dose gradually if this becomes necessary.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with atenolol. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common atenolol side-effects (these affect less than 1 in 10 people)What can I do if I experience this?
Feeling or being sick, stomach upsetStick to simple foods and drink plenty of water
Feeling dizzy, tired or light-headedGetting up and moving more slowly may help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments before standing. This often improves after the first week or two, but if it continues, speak with your doctor
Cold fingers or toes, a slow heartbeat, sweatingSpeak with your doctor if any of these become troublesome

If you experience any other symptoms which you think may be due to atenolol, speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • Manufacturer's PIL, Tenormin® 100 mg Tablets; AstraZeneca UK Limited, The electronic Medicines Compendium. Dated October 2015.
  • British National Formulary; 70th Edition (Sep 2015) British Medical Association and Royal Pharmaceutical Society of Great Britain, London

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Prof Cathy Jackson
Document ID:
3453 (v25)
Last Checked:
Next Review:
The Information Standard - certified member

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