Atenolol belongs to a group of medicines called beta blockers.

It’s used to treat high blood pressure and irregular heartbeats (arrhythmia).

It can also be used to prevent chest pain caused by angina.

If you have high blood pressure, taking atenolol helps prevent future heart disease, heart attacks and strokes.

Atenolol is sometimes prescribed to prevent migraines and help with anxiety. But it’s not officially approved to treat these conditions.

This medicine is only available on prescription.

It comes as tablets or as a liquid that you swallow. It can also be given as an injection, but this is usually done in hospital.

• Atenolol slows down your heart rate and makes it easier for your heart to pump blood around your body.
• It can make you feel dizzy, sick or tired, or give you constipation or diarrhoea. These side effects are usually mild and short-lived.
• Your very first dose of atenolol may make you feel dizzy, so take it at bedtime. After that, if you do not feel dizzy, you can take it in the morning.
• Do not stop taking atenolol suddenly, especially if you have heart disease. This can make your condition worse.
• Atenolol is known by the brand name Tenormin. Other brand names include Tenif (for atenolol mixed with nifedipine) and Co-tenidone (atenolol mixed with chlortalidone).

Atenolol can be taken by adults. It’s sometimes also prescribed for babies and children.

It’s not suitable for everyone. To make sure it’s safe for you, tell your doctor before starting atenolol if you have:

• had an allergic reaction to atenolol or any other medicine in the past
• low blood pressure or a slow heart rate
• serious blood circulation problems in your limbs (such as Raynaud’s phenomenon), which may make your fingers and toes tingle or turn pale or blue
• metabolic acidosis – when there’s too much acid in your blood
• lung disease or asthma

Tell your doctor if you’re trying to get pregnant, are already pregnant or breastfeeding.

You’ll usually take atenolol once or twice a day.

When you start taking atenolol, your doctor may advise you to take your first dose before bedtime because it can make you feel dizzy.

After the first dose, if you do not feel dizzy, you can take your medicine in the morning.

If you’re taking atenolol twice a day, you’ll usually 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.

Do not stop taking atenolol suddenly, especially if you have heart disease. This can make your condition worse.

If you want to stop taking your medicine, speak to your doctor. They may recommended reducing your dose gradually over a few weeks.

Dosage

How much you take depends on why you need atenolol.

For high blood pressure – the usual dose is 25mg to 50mg taken once a day.

For angina (chest pain) – the usual dose is 100mg taken once a day, or split into 2 50mg doses.

For irregular heartbeats (arrhythmia) – the usual dose is 50mg to 100mg taken once a day.

For migraine – the usual dose is 25mg to 100mg taken twice a day. Doctors sometimes prescribe atenolol for migraine, but it’s not officially approved for preventing it.

For children taking atenolol, your child’s doctor will work out the right dose by using their weight and age.