If you have had a myocardial infarction (a heart attack), it is common to be advised to take four medicines for the rest of your life. These are: aspirin (or similar), a beta-blocker, an ACE inhibitor and a statin. These medicines are likely to improve your outlook. Also, an additional antiplatelet medicine may be advised for a period of time. However, this is a general article and you may be advised differently if you have other diseases, develop complications, or have allergies or side-effects to certain medicines. Your doctor will advise what is best for your particular circumstances.
Why are these medicines prescribed after a myocardial infarction?
- To reduce the chance of another myocardial infarction (MI).
- To help to prevent heart disease from getting worse.
The medicines are usually taken each day for life. This leaflet discusses the typical situation. However, the exact medicines prescribed for you can depend on factors such as the type of MI you had, as well as any other illnesses you may also have. Your doctor will discuss your medicines in more detail.
Aspirin - helps to prevent blood clots
Aspirin works by reducing the stickiness of platelets. Platelets are tiny particles in the blood that help the blood to clot if a blood vessel is cut. However, if a blood clot forms inside a blood vessel taking blood to the heart muscle, it blocks the flow of blood. This can cause an MI. Therefore, aspirin reduces the chance of blood clots forming which reduces the chance of a further MI.
If you cannot take aspirin (for example, if you are allergic to it) then another antiplatelet medicine (such as clopidogrel or ticagrelor) may be used instead.
It is best to read the leaflet that comes with the tablets for a full list of instructions and possible side-effects. Some main points about aspirin include the following:
- The usual dose of aspirin is 75 mg per day. This is a low dose (antiplatelet dose) compared to the dose of aspirin used to ease pains and headaches.
- Side-effects are uncommon. An important side-effect is bleeding in the gut, which occurs in some people. If you have ever had a stomach or duodenal ulcer, or a bleed from your gut, you must tell your doctor. Extra care is needed when taking aspirin. For example, if you have had any of these conditions and take aspirin you may be advised to take another tablet that reduces stomach acid, to protect the gut.
- If you develop indigestion or heartburn whilst taking aspirin, you should stop your aspirin and see a doctor. These symptoms may indicate a gut problem or a bleed caused by the aspirin.
- Ideally, you should not take anti-inflammatory medicines or steroids if you take aspirin. Anti-inflammatory medicines, such as ibuprofen, are used to reduce inflammation in arthritis. Taking aspirin as well as them, increases the risk of a bleed in your gut. However, some people cannot do without anti-inflammatories. In this case, your doctor may suggest you take another tablet to reduce stomach acid. This will lower the risk of a bleed in the gut.
- Rarely, aspirin may cause a bleed in another part of the body (such as into the brain) and cause a stroke. You should not take aspirin if you have a bleeding disorder such as haemophilia.
- A small number of people are allergic to aspirin. If you are allergic to aspirin you may get breathing difficulties, wheezing or a swollen face and tongue if you take aspirin. If any of these symptoms occur, stop taking the aspirin and see a doctor.
- A small number of people with asthma cannot take aspirin, as it brings on asthma symptoms.
The above list may sound alarming but most people who take aspirin do not have any problems or side-effects. Also, the benefits of taking aspirin following an MI usually greatly outweigh the risk of any possible side-effects and problems.
Aspirin is usually taken for the rest of your life. Also, you will normally be advised to take another antiplatelet medicine (clopidogrel or ticagrelor) in addition to aspirin. However, this is usually only advised for a number of weeks or months, depending on the type and severity of your MI.
Beta-blockers - help to protect the heart
Beta-blockers work by easing the workload of the heart by blocking the beta receptors on heart muscle cells. A receptor is a tiny part on the wall of certain cells. There are different types of receptors throughout the body. The beta receptors on heart muscle cells are stimulated by the hormones adrenaline (epinephrine) and noradrenaline (norepinephrine). When the beta receptors are stimulated, they make the heart muscle cells work harder which increases the heart rate and blood pressure.
Beta-blocker medicines block beta receptors from being stimulated. This prevents the heart rate from going too fast, reduces blood pressure and helps to stabilise the electrical activity of the heart. Beta-blockers are also used to treat angina and high blood pressure. There are a few different beta-blockers for your doctor to chose from.
It is best to read the leaflet that comes with the tablets for a full list of instructions and possible side-effects. Some main points about beta-blockers include the following:
- Beta-blockers are not used in people with certain types of heart problems. For example, people with a very slow pulse, sick sinus syndrome or second- or third-degree atrioventricular (AV) block.
- Most people do not develop any side-effects. However, tell your doctor if you have any side-effects. The most common are: cool hands and feet, sleeping problems, difficulty getting and maintaining an erection, pins and needles, and tiredness. A change in dose or preparation may help if you develop any troublesome side-effects.
ACE inhibitors - help to protect the heart
One of the actions of an angiotensin-converting enzyme (ACE) inhibitor is to interfere with a chemical (enzyme) found in the bloodstream, called angiotensin. Blocking this enzyme widens blood vessels and lowers the blood pressure. This eases the burden on the heart. ACE inhibitors also appear to have a direct action on the heart, which has a protective effect. There are a few ACE inhibitors for your doctor to chose from.
It is best to read the leaflet that comes with the tablets for a full list of instructions and possible side-effects. Some main points about ACE inhibitors include the following:
- After the very first dose when you start your ACE inhibitor:
- Stay indoors for about four hours. Occasionally, some people feel dizzy. This is because the very first dose can cause a drop in blood pressure in a few people.
- If you do feel dizzy, sit or lie down and it will usually ease off.
- Your body quickly becomes used to the new medicine. After the first dose, there is no need to take any special precautions.
- You usually start with a low dose and build it up to a standard dose over 2-4 weeks.
- A blood test is usually done before starting an ACE inhibitor, and about two weeks after the first dose. This checks the function of the kidneys. (The kidneys are affected in a small number of people who take an ACE inhibitor.) A blood test at least every year is then usual.
Angiotensin-II receptor antagonists (also called angiotensin receptor blockers) have a similar effect as ACE inhibitors and are sometimes used as an alternative. If you have side-effects with an ACE inhibitor your doctor may suggest trying them instead.
Statins - to lower the cholesterol level
Statins work by reducing the amount of cholesterol that is made in the liver. Cholesterol contributes to the build-up of atheroma. Patches of atheroma are like fatty lumps that build up on the inside lining of blood vessels. A build-up of atheroma can lead to heart disease, strokes and other blood vessel problems. In general, the lower the cholesterol level, the better. Most people who have an MI are advised to take a statin.
Your GP or practice nurse will give you a target cholesterol level to aim for. This is often for your blood cholesterol level to come below 4 mmol/L. If the target is not reached, the dose may need to be increased or a different type of statin used.
You should have a blood test before starting treatment. This checks the level of cholesterol. It also checks if your liver is working properly. After starting treatment, you should have a blood test within 1-3 months, and again at 12 months. The blood test is to check that the liver has not been affected by the medication. The blood may also be checked to measure the cholesterol level to see how well the statin is working.
Most people who take a statin have no side-effects, or only minor ones. Read the information leaflet that comes with your particular brand for a full list of possible side-effects. These include: headache, pins and needles, abdominal pain, bloating, diarrhoea, feeling sick, and a rash.
Some points to remember about statins:
- Tell your doctor if you have any unexpected muscle pains, tenderness, cramps or weakness. This is because a rare side-effect of statins is a severe form of muscle inflammation.
- You should not take a statin if you have active liver disease, if you are are pregnant or intend to be pregnant, or if you are breast-feeding. You should stop taking a statin if you develop liver disease.
- Do not eat grapefruit or drink grapefruit juice if you are taking a statin. A chemical in grapefruit can increase the level of statin in the bloodstream which can make side-effects from the statin more likely.
- Various other medicines that you may take can interfere with statins - for example, some antibiotics and ciclosporin. The doses of either the statin or the other medicine may need to be adjusted. Therefore, if you are prescribed (or buy) another medicine, remind the doctor or pharmacist that you are on a statin in case it is one where an interaction may be possible.
- Tell a doctor if you develop chest symptoms such as unexplained shortness of breath or cough. This is because, in very rare cases, statins may cause a disease called interstitial lung disease.
This leaflet is about medications that are commonly prescribed if you have had an MI. However, it is not a substitute for advice from your doctor. You may be advised differently if you have other diseases, develop complications, or have allergies or side-effects to certain medicines. For example, if you develop angina or heart failure after an MI, you may be advised to take different medications.
How to use the Yellow Card Scheme
If you think you have had a side-effect to one of your medicines you can report this on the Yellow Card Scheme. You can do this online at the following web address: www.mhra.gov.uk/yellowcard.
The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that medicines may have caused. If you wish to report a side-effect, you will need to provide basic information about:
- The side-effect.
- The name of the medicine which you think caused it.
- Information about the person who had the side-effect.
- Your contact details as the reporter of the side-effect.
It is helpful if you have your medication - and/or the leaflet that came with it - with you while you fill out the report.
In addition to taking medication, there are various things you can do to help to reduce your risk of having another MI.
Medications are used in addition to any relevant lifestyle changes which also help to prevent heart disease from becoming worse. These include:
- Stopping smoking if you are a smoker.
- Taking regular exercise (unless advised otherwise by your doctor).
- Losing weight (if you are overweight).
- Eating a healthy diet, including oily fish at least 2-3 times a week.
- Drinking alcohol in moderation.
See separate leaflet called After a Myocardial Infarction which discusses lifestyle changes in more detail.
Further help & information
Further reading & references
- Secondary prevention in primary and secondary care for patients following a myocardial infarction, NICE Clinical Guideline (2007)
- Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events; NICE Technology Appraisals, December 2010
- Acute coronary syndromes - ticagrelor; NICE Technology Appraisal, October 2011
- Myocardial infarction - secondary prevention; NICE CKS, December 2007 (UK access only)
- Lipid modification - primary and secondary CVD prevention; NICE CKS, December 2008 (UK access only)
- Squizzato A, Keller T, Romualdi E, et al; Clopidogrel plus aspirin versus aspirin alone for preventing cardiovascular Cochrane Database Syst Rev. 2011 Jan 19;(1):CD005158.
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.
Dr Tim Kenny
Dr Hayley Willacy
Dr John Cox