Medicines can control cardiovascular Medicines can control cardiovascular disease
Drugs to treat heart conditions and stroke adjust the working of the heart or circulation of the blood.
Most are taken orally as tablets or capsules to be swallowed, but they can come in the form of tablets held under the tongue, aerosols or patches.
Drugs can also be administered directly into a vein or a muscle.
ACE inhibitors
ACE stands for angiotensin converting enzyme. Levels of angiotensin, a chemical which narrows blood vessels, are restricted by the drug, causing the arteries to dilate and leading to a fall in blood pressure.
Types of ACE inhibitor include enalaparil, captopril and lisinopril.
Side-effects include a fall in blood pressure, especially when combined with diuretics for the first time.
Anti-arrhythmic drugs
Anti-arrhythmic drugs act to control disturbances of the heart’s rhythm.
Amiodarone is very effective but it has side effects, including headache, flushing, dizziness and stomach upsets.
Flecainide is used for serious heart rhythm disturbances.
Propafenone is used to treat intermittent or paroxysmal atrial fibrillation – where the heart beats fast and irregularly and may lead to heart failure. Its use is usually avoided in patients with asthma or chronic lung disease.
Digoxin is used to treat atrial fibrillation. The drug slows the heart, relieving the symptoms of breathlessness and palpitation, but does not restore its regularity – additional treatment may be needed for this.
Anticoagulants
Clots consist of small blood cells clumped together – platelets – and a protein called fibrin.
Anticoagulants prevent fibrin forming, but may cause or aggravate bleeding. Regular blood tests are necessary to ensure clotting is within safe levels.
They are particularly useful for treating clots of the veins of the leg (deep vein thrombosis) and in preventing these clots travelling to the lung, causing pulmonary embolism. They do not dissolve existing blood clots.
They are often prescribed to prevent repeat heart attacks or strokes.
Heparin is usually given intravenously to urgently prevent further clotting.
Warfarin and other oral anticoagulants are given to prevent clotting over a long period. It is usually used for patients with artificial heart valves or heart valve disease, but is also given to people with irregular heart rhythm.
Aspirin (and other anti-platelet drugs)
Traditionally used as a painkiller, aspirin is also effective in preventing clotting of the blood, by reducing the “stickiness” of the platelets.
A smaller dose is needed than is required to relieve a headache.
It reduces the risk of dying after a heart attack or suffering a further heart attack or stroke. It is also useful for patients with angina and to prevent blood clotting in the vein grafts used in coronary artery bypass surgery.
But stroke patients should be aware that if their event was caused by a haemorrhage rather than a blood clot, aspirin could do more harm than good.
Other anti-platelet drugs such as clopidogrel and ticlopidine have recently been developed, which can be used around the time of angioplasty to reduce the risk of blood clotting.
Aspirin can cause indigestion, nausea, vomiting and constipation and so it is not recommended as a way of preventing heart attacks or strokes in healthy people.
Beta-blockers
Beta-blockers control the speed and force of heart beats by blocking the action of hormones such as adrenaline that make the heart beat faster and more vigorously.
They are effective in preventing angina. They can also lower raised blood pressure, reduce the risk of further heart attacks and help control abnormal heart rhythms.
Side-effects include constriction of the air passages and small blood vessels, leading to cold hands and feet. They can conceal low blood sugar levels in diabetics – “selective” beta-blockers are less likely to do this than other forms of the drug.
Tiredness or fatigue may also be experienced.
Calcium channel blockers (calcium antagonists)
Calcium antagonists reduce the amount of calcium entering the muscle cells of the arteries, causing them to relax.
This leads to the blood flow to the heart increasing and reducing the work the heart has to do to pump blood around the body.
Types of the drug include nifedipine, diltiazem and verapamil.
Side-effects include flushing, headache, dizziness, fainting, swelling of the ankles and stomach and gastro-intestinal problems.
Cholesterol-lowering drugs (lipid-lowering drugs)
Statins are the main type of drug used to reduce cholesterol levels. They can reduce levels of “bad” cholesterol – LDL (low-density lipoprotein) cholesterol – by more than 20%. They reduce the risk of dying of coronary heart disease by around 25%.
Statins are not suitable for people who have liver disease or who are pregnant or breastfeeding.
Two other forms of cholesterol-lowering drugs are available – fibrates and drugs which bind bile acids.
Diuretics
Diuretics, or “water tablets”, increase the output of water and salt in the urine.
They are effective in treating heart failure, where there is an excess of water and salt in the body, and in lowering high blood pressure.
They are often combined with digoxin and/or ACE inhibitors. To treat high blood pressure they are used alone or in combination with beta-blockers, calcium channel blockers, ACE inhibitors or other drugs.
Diuretics can cause low potassium levels, and in diabetics, high blood sugar levels.
Nitrates
Nitrates relax the muscles in the walls of the veins and arteries and make them wider. They are useful for relieving angina pain and preventing predictable attacks.
Glyceryl trinitrate tablets (also called GTN, trinitrate or nitroglycerin tablets) quickly relieve angina.
A throbbing headache can result when GTN tablets are first taken, but symptoms tend to fade with time.
Potassium channel activators
Potassium channel activators, a new type of drug for angina, have a similar effect to nitrates as they relax the walls of the coronary arteries and therefore improve blood flow.
“Clot-busters”- Thrombolytic drugs
Used only when there is an urgent need to dissolve a clot, usually after a heart attack, the most common form of the drug is streptokinase, which is given directly into a vein.
Repeat doses of some thrombolytic drugs, such as streptokinasae should not be given for several years.
However, this is not the case for others, such as alteplase, reteplase and tenecteplase.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764042.stm
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