A (cardioselective) beta-blocker
Atenolol
A heart-selective beta-blocker used to control heart rate in atrial fibrillation and angina, and sometimes for blood pressure.
What is Atenolol?
Atenolol is a long-established cardioselective beta-blocker that slows the heart rate and reduces its workload. It is used to control the heart rate in atrial fibrillation, to treat angina and high blood pressure, and to ease some symptoms after a heart attack.
Education and reference only. This is a plain-language guide to Atenolol — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Atenolol is a long-established "cardioselective" beta-blocker — meaning it acts mainly on the heart. It is used to control the heart rate in atrial fibrillation, to prevent the chest pain of angina, and to lower blood pressure. For uncomplicated high blood pressure it is no longer a first-choice option in the UK — calcium-channel blockers, ACE inhibitors and ARBs are generally preferred — but it remains widely used where there is a clear heart reason to use a beta-blocker. It is taken as a once- or twice-daily tablet, long-term.
How it works
Atenolol blocks beta receptors in the heart, reducing the effect of adrenaline-type stress signals. This slows the heart rate, eases the force of each beat and lowers the heart's workload and oxygen demand — which is why it both steadies a fast, irregular rate in atrial fibrillation and helps prevent the pain of angina. The same calming of the heart and circulation also brings blood pressure down. Atenolol is cleared mainly by the kidneys, so it tends to build up if kidney function is reduced.
Company & origin
Originated / developed by: AstraZeneca (originated at ICI).
Atenolol is a cardioselective beta-blocker developed by Imperial Chemical Industries (ICI, later Zeneca, now AstraZeneca) in the United Kingdom in the 1970s. It was first introduced around 1976 and marketed as Tenormin.
What it treats
Conditions Atenolol is used for
Practical use
How to take Atenolol
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Usually taken once a day at about the same time.
- Swallow the tablet with water, with or without food.
- If you miss a dose, skip it and take the next one as usual — do not double up.
- Do not stop suddenly; the dose should be reduced gradually to avoid rebound effects.
- Tell your doctor if you have asthma or breathing problems before taking it.
Weighing it up
Advantages & disadvantages of Atenolol
Advantages
- Simple once-daily dosing.
- Largely heart-selective, so generally better tolerated than non-selective beta-blockers.
- Long track record and inexpensive.
- Effective for rate control and angina.
Disadvantages
- No longer a first choice for high blood pressure alone in many guidelines.
- Can cause tiredness, cold extremities and a slow heart rate.
- Must not be stopped abruptly.
- Can mask the warning signs of low blood sugar in diabetes.
Practical use
Good to know
Atenolol must never be stopped abruptly — suddenly stopping a beta-blocker can trigger a rebound rise in heart rate, raised blood pressure and chest pain, which can be dangerous in heart disease. If it needs to stop, it is reduced gradually under guidance. Tiredness and cold hands and feet are common, especially early on. Because it is cleared by the kidneys, the prescriber takes kidney function into account. It can also blunt the early warning signs of a low blood sugar, which matters for people with diabetes.
Who should not take it / use with caution
- People with asthma or significant reversible airways disease — beta-blockers can trigger wheeze and are usually avoided, or used only with great caution and specialist input.
- People with certain slow or blocked heart rhythms (e.g. some types of heart block), a very slow heart rate or very low blood pressure, or acutely decompensated heart failure.
- Used with caution in reduced kidney function (atenolol is cleared by the kidneys and can accumulate), severe circulation problems in the limbs, and in pregnancy and breastfeeding — assessed individually.
Monitoring
- Heart rate and blood pressure
- Kidney function, since atenolol is cleared by the kidneys
- Breathing in anyone with airways disease, and symptoms during any dose change
Side effects
- Tiredness, cold hands and feet, and a slow pulse.
- Dizziness or light-headedness, especially when starting; vivid dreams or disturbed sleep.
- Wheeze or breathlessness in people prone to it; rarely, mood changes — report anything troublesome.
Key interactions
- Other heart-rate-lowering medicines (e.g. diltiazem, verapamil, digoxin) can slow the heart too much.
- Care alongside other blood-pressure-lowering medicines, which can add up to excessive lowering.
- Can mask the warning signs of a low blood sugar (such as a racing heart) in people with diabetes.
Available as: Tablets (several strengths); a liquid is available for those who cannot swallow tablets.
Answers
Atenolol: frequently asked questions
Can I stop atenolol suddenly?
No — stopping a beta-blocker abruptly can cause a rebound fast heart rate, raised blood pressure and chest pain, and can be dangerous in heart disease. If it needs to stop, it is reduced gradually under guidance.
Why isn't atenolol a first choice for high blood pressure any more?
For uncomplicated high blood pressure, UK guidance generally prefers calcium-channel blockers, ACE inhibitors or ARBs, which tend to control pressure and protect against stroke at least as well with fewer metabolic effects. Atenolol is still very much used when there is a heart reason for a beta-blocker, such as atrial fibrillation or angina.
Can I take atenolol if I have asthma?
Beta-blockers can trigger wheezing and are usually avoided, or used only with great caution and specialist advice, in asthma. Always tell your prescriber about any asthma or breathing condition so the right choice is made.
Does atenolol affect diabetes?
It can blunt some of the early warning signs of a low blood sugar (such as a racing heart), so people with diabetes should be aware and monitor as advised. It does not usually change blood-sugar control much.
Is Tenormin the same as atenolol?
Yes — atenolol is the generic (active-ingredient) name and Tenormin is a brand name; both contain the same active ingredient.
The wider class
About Beta-blockers
Atenolol belongs to the beta-blockers class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF: Atenolol.
- electronic Medicines Compendium (SmPC): Atenolol.
- NICE CKS: Atenolol.
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