Why are certain medicines prescribed after a heart attack?
- To reduce the chance of a further heart attack.
- 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 heart attack you had, as well as any other illnesses you may also have. Your doctor will discuss your medicines in more detail.
Antiplatelet medicines - help to prevent blood clots
Low-dose aspirin is an antiplatelet medicine. It 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 a heart attack. Therefore, aspirin reduces the chance of blood clots forming which reduces the chance of a further heart attack.
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 develop 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 a heart attack usually greatly outweigh the risk of any possible side-effects and problems.
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. Aspirin is usually taken for the rest of your life.
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 choose 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.
Angiotensin-converting enzyme 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 choose 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 to 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 a heart attack 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.
Further reading and references
Myocardial infarction with ST-segment elevation: The acute management of myocardial infarction with ST-segment elevation; NICE Clinical Guideline (July 2013)
2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation; European Society of Cardiology (August 2015)
Ibanez B, James S, Agewall S, et al; 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation: The Task Force for the management of acute myocardial infarction in patients presenting with ST-segment elevation of the European Society of Cardiology (ESC). Eur Heart J. 2017 Aug 26. doi: 10.1093/eurheartj/ehx393.
Valgimigli M, Bueno H, Byrne RA, et al; 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease developed in collaboration with EACTS: The Task Force for dual antiplatelet therapy in coronary artery disease of the European Society of Cardiology (ESC) and of the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2017 Aug 26. doi: 10.1093/eurheartj/ehx419.
Unstable angina and NSTEMI; NICE Clinical Guideline (March 2010 - last updated November 2013)
Acute coronary syndrome; Scottish Intercollegiate Guidelines Network - SIGN (2016)
Myocardial infarction: cardiac rehabilitation and prevention of further MI; NICE Clinical Guideline (November 2013)
2014 ESC/EACTS Guidelines on myocardial revascularization; The Task Force on Myocardial Revascularization of the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery (Aug 2014)
Mehta LS, Beckie TM, DeVon HA, et al; Acute Myocardial Infarction in Women: A Scientific Statement From the American Heart Association. Circulation. 2016 Mar 1133(9):916-47. doi: 10.1161/CIR.0000000000000351. Epub 2016 Jan 25.
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