Atenolol, nifedipine (Beta-adalat)
How does it work?
Beta-adalat capsules contain two active ingredients: atenolol, which is a type of medicine called a beta-blocker, and nifedipine, which is a type of medicine called a calcium channel blocker.
Atenolol works by blocking beta receptors that are found in the heart. This reduces the action of adrenaline and noradrenaline on the heart, causing it to beat more slowly and with less force. In turn, this reduces the pressure at which the blood is pumped out of the heart and around the body, which helps to reduce blood pressure. Atenolol can therefore be used to lower high blood pressure.
Atenolol's action in slowing the rate and force of the heartbeat also reduces the energy used by the heart to pump blood around the body. This reduces the heart's need for oxygen, which means that atenolol can also be used in the management of angina. Angina is chest pain that occurs because the heart does not get enough oxygen to meet demand, for example during exercise. This is usually as a result of hardening or narrowing of the arteries that supply blood to the heart. Atenolol reduces the workload of the heart and so decreases the amount of oxygen that it needs to pump blood around the body. This helps to prevent attacks of angina.
Nifedipine works by slowing the movement of calcium through the muscle cells that are found in the walls of blood vessels. It does this by blocking 'calcium channels' in these muscle cells. Calcium is needed by muscle cells in order for them to contract, so by depriving them of calcium, nifedipine causes the muscle cells to relax.
Nifedipine acts specifically on the muscle cells in the walls of arteries, causing them to relax. This allows the arteries in the body to widen, an effect that has two main uses.
The relaxing and widening of the small arteries in the body decreases the resistance that the heart has to push against in order to pump the blood around the body. This reduces the pressure within the blood vessels. Nifedipine can therefore be used to lower high blood pressure.
The widening effect on the small arteries and the arteries in the heart also improves the blood and therefore oxygen supply to the heart. Nifedipine can therefore be used in the management of angina. As nifedipine improves this oxygen supply, and also reduces the effort the heart has to make to pump blood, it is used to prevent angina attacks.
Atenolol and nifedipine have a combined effect on lowering high blood pressure and preventing angina attacks.
What is it used for?
- Angina pectoris (as a regular treatment to prevent attacks, when therapy with either a beta-blocker or calcium channel blocker alone is ineffective).
- High blood pressure (when therapy with either a beta-blocker or calcium channel blocker alone is ineffective).
How do I take it?
- Beta-adalat capsules can be taken either with or without food. The capsules should be swallowed whole with a drink of water. They should not be opened, crushed or chewed.
- The dose prescribed and how often the medicine needs to be taken depends on the condition being treated. It is important to follow the instructions given by your doctor. These will be printed on the dispensing label your pharmacist has put on the packet of medicine.
- You should not drink grapefruit juice while you are taking this medicine, as it can increase the level of nifedipine in your blood and thus increase the chance of getting side effects.
- It is important that you don't suddenly stop taking this medicine unless your doctor tells you to.
- This medicine may cause fatigue and dizziness. You should take care when performing potentially hazardous activities, such as driving or operating machinery, until you know how this medicine affects you and are sure you can perform such activities safely.
- You should not stop taking this medicine suddenly, particularly if you have ischaemic heart disease (inadequate flow of blood to the heart, eg angina). When treatment with this medicine is stopped it should be done gradually, usually over one to two weeks, following the instructions given by your doctor.
- This medicine should not be taken to treat an angina attack, as it does not work quickly enough. It should be used regularly, as prescribed, to prevent angina attacks, and you should keep your glyceryl trinitrate (GTN) sublingual tablets or spray with you at all times to use if you do have an angina attack.
- If you go into hospital or to the dentist to have an operation you should tell the person treating you that you are taking this medicine. This is because your blood pressure may fall too low if you are given certain types of anaesthetics while taking this medicine.
Use with caution in
- Elderly people.
- Decreased liver function.
- Decreased kidney function.
- People with a history of heart failure or a weak heart.
- People with slowed conduction of electrical messages between the chambers of the heart (1st degree heart block).
- A severe form of chest pain not caused by exertion (Prinzmetal's or variant angina).
- Chronic obstructive pulmonary disease (COPD).
- History of asthma, wheezing or any other breathing difficulties.
- People with poor blood circulation in the arteries of the extremities, eg hands and feet (avoid if problems are severe - see below).
- Diabetes (this medicine may mask the symptoms of low blood sugar, such as increased heart rate and tremor, and the dose of your diabetes medicine may need adjusting).
- People with a history of sudden drops in blood sugar levels (hypoglycaemia).
- Overactive thyroid gland (this medicine may mask the symptoms of a thyroid storm or thyrotoxicosis).
- History of allergies.
- Abnormal muscle weakness (myasthenia gravis).
Not to be used in
- People with a serious defect in the heart's electrical message pathways, resulting in decreased function of the heart (2nd or 3rd degree heart block).
- Uncontrolled heart failure.
- People with a very slow heart rate (bradycardia).
- Unstable angina.
- People with a condition called aortic stenosis, which is narrowing of the main artery from the heart through which blood is pumped to the rest of the body.
- A problem common in the elderly, related to poor control of the working of the heart (sick sinus syndrome).
- Failure of the heart to maintain adequate circulation of blood around the body (cardiogenic shock).
- People who have recently had a heart attack (in the last month).
- Low blood pressure (hypotension).
- Severe conditions involving poor blood circulation in the arteries of the extremities, eg hands and feet (peripheral arterial disorders such as Raynaud's syndrome or intermittent claudication).
- People with an increase in the acidity of the blood (metabolic acidosis).
- Untreated tumour of the adrenal gland (phaeochromocytoma). If you are being treated for phaeochromocytoma you will be given another medicine called an alpha-blocker in combination with this one.
- Severely decreased kidney function.
- This medicine is not recommended for children.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine should not be used during pregnancy. Beta-blockers reduce blood flow to the placenta, which could increase the chance of premature delivery or death of the foetus. They may also slow the baby's heartbeat, cause its blood sugar to drop, or restrict its growth in the womb. If you think you could be pregnant while taking this medicine, or want to try for a baby, it is important to seek medical advice from your doctor. It is important that you don't stop taking this medicine suddenly.
- Both atenolol and nifedipine pass into breast milk. As atenolol could potentially cause the baby's heart rate to slow down or its blood sugar to fall, it is recommended that this medicine is not used by breastfeeding mothers. Seek medical advice from your doctor.
- Do not stop taking this medication except on your doctor's advice.
- This medication is to be swallowed whole, not chewed.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.
- Excessive fluid retention in the body tissues, resulting in swelling (oedema).
- Sexual problems such as impotence.
- Bleeding in the skin (purpura).
- Cold hands and feet.
- Slow heart rate (bradycardia).
- Narrowing of the blood vessels in the hands leading to periods of white, painful hands (Raynaud's disease).
- Cramping pain in the leg (calf) muscles on exertion (intermittent claudication).
- Awareness of your heart beat (heart palpitations).
- Breathing difficulties due to a narrowing of the airways (bronchospasm).
- Temporary worsening of chest pain (angina) at the start of therapy.
- Disturbed sleep.
- Dry mouth.
- Dry or irritated eyes.
- Visual disturbances.
- Passing urine more often.
- Skin reactions such as rash, swelling, burning sensation of hands and feet.
- Hair loss.
- Reduced platelet count in the blood (thrombocytopenia).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
This medicine is likely to have an additive effect with other medicines that decrease blood pressure, particularly medicines that are used to treat high blood pressure (antihypertensives). This may cause dizziness, which can usually be relieved by lying down until the symptoms pass. If you feel dizzy while taking this medicine in combination with other medicines that can lower blood pressure you should let your doctor know, as your doses may need adjusting. Other medicines that decrease blood pressure include the following:
- ACE inhibitors, eg enalapril
- alpha-blockers such as prazosin
- angiotensin II receptor antagonists such as losartan
- antipsychotics such as chlorpromazine
- benzodiazepines, eg temazepam, diazepam
- other beta-blockers such as propranolol
- other calcium channel blockers such as felodipine. (This medicine should not be used in combination with the calcium channel blockers verapamil, or diltiazem.)
- clonidine (If atenolol is taken in combination with clonidine there is also a risk of a rebound increase in blood pressure if the clonidine is suddenly stopped. If you are taking both these medicines it is important to keep taking both of them unless otherwise directed by your doctor. When stopping treatment, this medicine should be stopped several days before slowly stopping the clonidine.)
- diuretics, eg furosemide, bendroflumethiazide
- dopamine agonists, eg bromocriptine, apomorphine
- MAOI antidepressants, eg phenelzine
- nitrates, eg glyceryl trinitrate
This medicine may reduce the blood sugar lowering effect of some medicines used to treat diabetes. People with diabetes should carefully monitor their blood sugar while taking this medicine, as atenolol can also mask some of the signs of low blood sugar, such as increased heart rate and tremor.
There may be an increased risk of slow heart rate and heart block if atenolol is used in combination with the following medicines:
- medicines for irregular heartbeats (anti-arrhythmics), eg amiodarone, flecainide, quinidine.
There may be an increased risk of coldness, numbness or tingling of the hands and feet if ergot derivatives such as ergotamine or methysergide (used to treat migraines) are taken in combination with atenolol.
The blood level of nifedipine may be increased by the following medicines:
If you take any of these in combination with Beta-adalat, you should tell your doctor if you feel dizzy or experience any other side effects, as your dose may need to be reduced.
The blood level of nifedipine may be reduced by the following medicines:
- rifampicin (this should not be taken in combination with Beta-adalat, as it will make the nifedipine component ineffective).
If nifedipine is taken in combination with diltiazem, the blood level of both medicines may increase and their doses may need to be adjusted.
Nifedipine may increase blood levels of the following medicines:
Nifedipine may decrease the blood level of quinidine.
Your doctor may want to monitor the level of these medicines in your blood if you take them with nifedipine.
The following medicines may reduce the blood pressure lowering effect of this medicine:
- corticosteroids, such as dexamethasone or prednisolone
- oestrogens, such as those in the contraceptive pill
- regular use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, diclofenac or indomethacin (occasional painkilling doses are unlikely to have a significant effect).
Other medicines containing the same active ingredients
Tenormin contains atenolol on its own. (Atenolol is also available without a brand name, ie as the generic medicine.)
Adalat contains nifedipine on its own. (There are also several other brands of nifedipine available and it too is available as the generic medicine.)