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Sotalol - Brand name: Sotacor

On this page

  1. About sotalol
  2. Key facts
  3. Who can and cannot take sotalol
  4. How and when to take sotalol
  5. Side effects
  6. How to cope with side effects of sotalol
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions about sotalol

1. About sotalol

Sotalol belongs to a group of medicines called beta blockers.

It's used to treat atrial fibrillation and other conditions that cause an irregular heartbeat (arrhythmia).

This medicine is only available on prescription. It comes as tablets.

2. Key facts

  • Sotalol slows down your heart rate and makes it easier for your heart to pump blood around your body.
  • It starts to work after about 4 hours, but it can take 2 to 3 days to fully take effect.
  • Your first dose of sotalol 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.
  • You'll usually take sotalol either once a day, in the morning, or twice a day, in the morning and evening.
  • The main side effects of sotalol are feeling dizzy or sick, feeling tired, having diarrhoea or a headache. These are usually mild and short-lived. You're more likely to have side effects if you're on a very high dose of sotalol.

3. Who can and cannot take sotalol

Sotalol can be taken by adults and children over the age of 12 years. It can also be taken by children under the age of 12 on the advice of their specialist.

It is not suitable for everyone.

To make sure it's safe for you, tell your doctor before starting to take sotalol if you have:

  • ever had an allergic reaction to sotalol or any other medicine
  • low blood pressure or a slow heart rate
  • heart failure which is getting worse, heart disease, or you've recently had a heart attack
  • any problems with your kidneys
  • an overactive thyroid (hyperthyroidism) – sotalol may make it more difficult to recognise the warning signs of having too much thyroid hormone in your body (thyrotoxicosis)
  • severe blood circulation problems in your limbs (such as Raynaud's phenomenon), which may make your fingers and toes tingle or turn pale or blue (this may be less noticeable if you have black or brown skin)
  • metabolic acidosis – when there is too much acid in your blood
  • a lung disease or severe asthma
  • severe diarrhoea

4. How and when to take sotalol

Take sotalol exactly as your doctor has told you, and follow the instructions on the label. If you're not sure, check with your doctor or pharmacist.

You'll usually take sotalol once or twice a day.

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 sotalol in the morning.

If you take sotalol twice a day, try to take it in the morning and in the evening.


Take sotalol even if you feel well, as you will still be getting the benefits of the medicine.


Sotalol tablets come in different strengths: 40mg, 80mg and 160mg.

The usual dose of sotalol is between 80mg and 320mg a day. If you get irregular heartbeats several times a day, your doctor may prescribe a higher daily dose of up to 640mg.

If you are older or have kidney problems, your doctor may give you a lower dose.

How to take it

You can take sotalol with or without food, but it's best to do the same each day.

Swallow the tablets whole with a drink of water.

If you forget to take it

If you miss a dose of sotalol, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just leave out the missed dose and take your next dose at the usual time.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

If you take too much

Taking too much sotalol can slow down your heart rate and make it difficult to breathe. It can also cause dizziness and trembling.

The amount of sotalol that can lead to an overdose varies from person to person.

Urgent advice: Contact 111 for advice now if:

  • you take more than your prescribed dose of sotalol

Go to or call 111

If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.

Take the sotalol packet, or the leaflet inside the packet, plus any remaining medicine with you.

Immediate action required: Go to A&E now if:

You take more than your prescribed dose of sotalol and:

  • your heart rate (pulse) has slowed down
  • you are having difficulty breathing

Find your nearest A&E.

5. Side effects

Like all medicines, sotalol can cause side effects in some people, but many people have no side effects or only minor ones. Side effects often improve as your body gets used to the medicine.

Common side effects

These common side effects happen in more than 1 in 100 people. They're usually mild and short-lived.

Talk to your doctor or pharmacist if the side effects bother you or last more than a few days:

  • headaches
  • feeling tired, dizzy or weak
  • cold fingers or toes
  • diarrhoea, feeling or being sick (nausea or vomiting)
  • stomach pain

Serious side effects

It happens rarely, but some people have serious side effects when taking sotalol.

Call 111 or call your doctor now if:

  • the whites of your eyes turn yellow, your skin turns yellow although this may be less obvious on brown or black skin, or you have pale poo or dark pee – these can be signs of liver problems
  • you get nosebleeds that last for more than 10 minutes, unexplained bruising, or you bruise more easily than usual – these can be signs of low numbers of platelets in your blood (thrombocytopenia)

Immediate action required: Call 999 or go to A&E if:

  • you have shortness of breath with a cough which gets worse when you exercise (like walking upstairs), swollen ankles or legs, chest pain, or an irregular heartbeat – these are signs of heart problems
  • you have shortness of breath, wheezing and tightening of your chest – these can be signs of lung problems

Serious allergic reaction

In rare cases, sotalol may cause a serious allergic reaction (anaphylaxis).

Immediate action required: Call 999 now if:
  • your lips, mouth, throat or tongue suddenly become swollen
  • you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
  • your throat feels tight or you're struggling to swallow
  • your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
  • you suddenly become very confused, drowsy or dizzy
  • someone faints and cannot be woken up
  • a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of sotalol. For a full list, see the leaflet inside your medicine packet.


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

6. How to cope with side effects of sotalol

What to do about:

  • headaches – make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller. Headaches usually go away after the first week of taking sotalol. Talk to your doctor if the headaches last longer than a week or are severe.
  • feeling tired, dizzy or weak – if sotalol makes you feel dizzy or weak, stop what you're doing and sit or lie down until you feel better. Do not drive, ride a bike or use tools or machinery if you're feeling tired. Do not drink alcohol as it will make you feel worse.
  • cold hands or feet – put your hands or feet under warm running water, massage them and wiggle your fingers and toes. Do not smoke or have drinks with caffeine in, as these can make your blood vessels narrower and restrict your blood flow. Smoking also makes your skin colder. Try wearing mittens (they're warmer than gloves) and warm socks. Do not wear tight watches or bracelets.
  • diarrhoea, feeling or being sick – stick to simple meals and do not eat rich or spicy food. It might help to take your sotalol after you've eaten. Drink plenty of water or other fluids. If you're being sick, try small frequent sips to avoid dehydration. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor. If you take contraception and you're being sick or have severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.
  • stomach pain – try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your tummy may also help. If you are in a lot of pain, speak to your pharmacist or doctor.

7. Pregnancy and breastfeeding

Sotalol and pregnancy

Sotalol can be used in pregnancy, particularly if you have problems with your heart.

However, always check with your doctor that they are happy for you to keep taking it. They may wish to review your medicine and may recommend other medicines instead.

If you do take sotalol in pregnancy then you may need extra scans to check that your baby is growing at a normal rate.

Sotalol and breastfeeding

If your doctor or health visitor says that your baby is healthy, it's OK to take sotalol while you're breastfeeding.

Sotalol can pass into breast milk in quite high amounts, but studies looking at sotalol have not shown any side effects in breastfed babies. Other beta blockers have been linked with side effects in breastfed babies.

It's important to keep taking sotalol to keep you well. Breastfeeding will also benefit both you and your baby.

If you notice that your baby is not feeding as well as usual, or seems unusually sleepy, seems much paler than usual, or if you have any other concerns about your baby, talk to your health visitor, midwife or doctor as soon as possible. They may recommend a different medicine for you to take.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

For more information about how sotalol can affect you and your baby during pregnancy, read this leaflet on the Best Use of Medicines in Pregnancy (BUMPS) website.

8. Cautions with other medicines

There are some medicines that may affect the way sotalol works.

Tell your doctor if you're taking:

Mixing sotalol with herbal remedies or supplements

There's very little information about taking herbal remedies and supplements with sotalol.

Important: Medicine safety

Tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

9. Common questions about sotalol

How does sotalol work?

Sotalol is a type of medicine called a beta blocker.

Like other beta blockers, sotalol works by changing the way your body responds to some nerve impulses, especially in the heart. It slows down your heart rate and makes it easier for your heart to pump blood around your body.

How long does sotalol take to work?

Sotalol starts to work after about 4 hours, but it can take 2 to 3 days to fully take effect.

How long will I take it for?

Usually, treatment with sotalol is long term, even for the rest of your life.

Is it safe to take for a long time?

Sotalol is generally safe to take for a long time. In fact, it works best when you take it for a long time.

What will happen if I stop taking it?

Talk to your doctor if you want to stop taking sotalol.

Stopping sotalol suddenly can make your condition worse.

If you're bothered by side effects, your doctor may be able to prescribe a different medicine for your heart problems.

If you stop taking sotalol, it will take about 4 days for it to be completely out of your body.

Do I need to have regular blood tests if I'm taking sotalol?

You will have regular blood tests to check that your kidneys are healthy (because they remove sotalol from the body, so it's important they work properly).

Your blood test may also check that you have the right amounts of potassium and magnesium in your blood. If there's too little of these in your blood it can cause side effects.

How does it compare with other heart medicines?

Sotalol is not considered as a typical beta blocker. This is because it is not generally used to treat high blood pressure and is mainly used for irregular heartbeats. Sotalol is classed as a potassium blocker.

There are 4 main types of medicines for treating irregular heartbeats:

  • sodium channel blockers like flecainide
  • beta blockers like propranolol and atenolol
  • potassium blockers like sotalol and amiodarone
  • calcium channel blockers like verapamil

They all work a little bit differently to help regulate your heartbeat, and the side effects can also be different. Sometimes you may have to try other medicines for an irregular heartbeat if you get side effects.

Will I need to stop sotalol before surgery?

Tell your doctor that you're taking sotalol if you're going to be put to sleep (using general anaesthetic), or you're having any kind of major operation.

Your doctor may advise you to stop taking sotalol before surgery. This is because sotalol can lower your blood pressure too much when it's combined with some anaesthetics.

Can I drink alcohol with it?

Drinking alcohol can increase the risk of side effects with sotalol. It can make you feel dizzy or lightheaded.

During the first few days of taking sotalol or after an increase in your dose, it's best to stop drinking alcohol until you see how the medicine affects you.

If you find sotalol makes you feel dizzy it's best to stop drinking alcohol.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking sotalol.

Eating a healthy, balanced diet can help if you have a heart condition.

Will it affect my contraception?

Sotalol will not stop your contraception working.

However, if sotalol makes you sick (vomit) or you have severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

Read more about what to do if you're on the pill and you're being sick or have diarrhoea.

Some types of hormonal methods of contraception, like the combined pill and contraceptive patch, are sometimes not recommended if you have heart problems. Talk to your doctor if you're taking or using combined hormonal contraception.

Will it affect my fertility?

There's no evidence to suggest that taking sotalol reduces fertility in either men or women.

Will it affect my sex life?

Some people taking sotalol say their sex drive goes down or they cannot get an erection. However, this is not a common side effect and there is not enough evidence to say for sure that sotalol is causing it.

If you're having problems with your sex life, talk to your doctor.

Do I need to avoid playing sports?

You do not need to stop playing sports if you take sotalol. But do not push yourself too much.

Regular exercise is good for you because it lowers blood pressure by keeping your heart and blood vessels in good condition. Be aware, though, that in some sports sotalol is not allowed if you're competing at a high level.

Can I drive or ride a bike?

Sotalol can make some people feel dizzy, especially when they first start taking it or after taking a bigger dose. If this happens to you, do not drive a car, ride a bike, or use tools or machinery.

Can lifestyle changes help my heart?

You can boost the health of your heart by making some key lifestyle changes:

  • Quit smoking – smoking increases your heart rate and blood pressure. Quitting smoking brings down your blood pressure and relieves heart failure symptoms. Try to avoid secondhand smoke.
  • Cut down on alcohol – drinking too much alcohol raises blood pressure over time. It makes heart failure worse too. Try to keep to the recommended guidelines of no more than 14 units of alcohol a week. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
  • Exercise – regular exercise lowers blood pressure by keeping your heart and blood vessels in good condition. It does not need to be too energetic, walking every day will help.
  • Eat well – aim to eat a diet that includes plenty of fruit and vegetables, wholegrains, fat-free or low-fat dairy products and lean proteins. It's a good idea to follow these tips for a lower salt diet. Eating too much salt is the biggest cause of high blood pressure. The more salt you eat, the higher your blood pressure will be. Aim for no more than 6g of salt a day.
  • Manage stress – when you're anxious or upset, your heart beats faster, you breathe more heavily and your blood pressure often goes up. This can make heart failure worse too. Find ways to reduce stress in your life. To give your heart a rest, try napping or putting your feet up when possible. Spend time with friends and family to be social and help avoid stress.

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Page last reviewed: 17 November 2021
Next review due: 17 November 2024