Drugs used in heart therapy
Patient Perspective Paper 2
These notes are a patient’s view on drugs and I hope that you might find them helpful. You will find more detail in the BHF’s booklets and leaflets on the subject.
As I take many of these, I was keen to know what I was taking them for and I expect that some of you feel in the same position. It is important to realise that a particular drug may be doing more than one job for one person that may be different for another. Therefore a “cocktail” of drugs are usually prescribed, as their action and side-effects may balance each other out. I also make the obvious point that most have side-effects. You will therefore be asked to have regular blood tests to check that any adverse reactions are within tolerable limits
I must emphasise once again that notes such as these are very much my personal interpretation and I apologise but take no responsibility for any inaccuracy. If you are worried in any way concerning your own position, please consult your own doctor or consultant. I have tried to group the drugs into various categories- the name or brand name is given in italics.
ß– blockers. Carvedilol, metoprolol, bisoprolol.
Calcium channel blockers. Nifedipine.
Potassium channel activators. Nicorandil
Nitrates. GTN( Glycerol trinitrate). Isosorbide mononitrate or dinitrate.
These drugs are used in the treatment of angina and to lower blood-pressure. ß –blockers block the action of adrenaline so in essence they slow the heart down. Calcium channel blockers reduce the amount of calcium entering the muscle cells of the arteries causing them to relax and widen. Potassium channel activators relax the walls of the arteries to relieve angina. Nitrates act in a similar way: GTN can be in the form of a spray or tablets taken under the tongue. Nitrates can also be used as a slow-release preparation. A common side-effect of a beta-blocker is dizziness through the lowering of blood pressure and heart-rate.
Anti-platelet drugs. Aspirin and Clopidogrel
These drugs reduce the risk of a heart attack by reducing the stickiness of platelets within the blood so making it less susceptible to clot. Aspirin is normally taken as a 75g dose once a day – this is much less than a dose taken for a headache! (A normal pill is about 300g). Clopidogrel is a newer drug which is often used after someone has received a stent from an angioplasty operation. A heart patient may be on aspirin for the rest of their lives but one is normally taken off Clopidogrel after a year. Aspirin may cause gastric irritation or internal bleeding so it must be taken with or after food.
Clotbusters. Streptokinase, Alteplase, Tenecteplase.
These thrombolytic drugs are used only when there is an urgent need to dissolve a clot – e.g. when you are experiencing severe heart symptoms or an actual “heart attack”. They are given as a single dose or more usually in a drip. Hence, if you are rushed to hospital in an emergency, the ambulance crew are instructed to insert a valve to receive this drip in your hand whilst they are taking you to A&E.
ACE Inhibitors. Ramipril, Lisonopril, Peridopril.
Antiogensin II antagonists. Losartan, Valsartan, Irbesartan.
ACE stands for “antiogensin converting enzyme”. Antiogensin is a chemical which has a powerful narrowing effect on the blood vessels. The drug reduces the activity of the enzyme so making the arteries relax and widen. Losartan etc are newer drugs which have different side-effects but essentially act in the same way. Both sets of drugs are useful in the treatment of angina and high blood pressure or for those who have experienced a heart attack.
Diuretics. Furosemide. Spironolactone.
Diuretics remove water and salt in your system into your urine (they therefore increase the visits to the toilet!). Their main function is to reduce the strain on the heart. Furosemide can cause you to lose potassium so you will be regularly checked for this – eat more bananas! Spironolactone does not have this problem to the same extent but it has other side-effects which may therefore mean you will not be prescribed it. In the early stages of heart therapy after a heart attack you may be prescribed both drugs. Both drugs cause reduced blood pressure. It is important not to miss a dose but the time can be varied to suit one's plans for the day. We found that in a recent meeting experience varied between 15 minutes and three hours before the effects of the drug "kicked in".
Anti-arrhythmic drugs Amiodarone. Flecanide. Propafenone. Dronedarone.
Digoxin.
Of the first four, amiodarone is the one more usually used. It has been proved to be very effective in controlling disturbances of the heart rhythm but it does have quite a few side-effects, which need to be regularly checked. The main five are: liver function (avoid excess alcohol), thyroid function (very common), sunburn (avoid direct sunlight), the eyes and potassium level.
Dronedarone is a new drug which has the advantage of not containing iodine, which is thought to be one of the main factors in the effects on the liver and the thyroid. It is licensed to treat atrial fibrillation only at the moment and initial indications are that it is not as good as amiodarone, certainly for VF disturbances.
Digoxin is often used to treat atrial fibrillation which makes the heart beat quickly and irregularly. Digoxin and similar drugs have been around for some 200 years (originally came from the foxglove plant) used to slow the heart. It may however not restore the regularity of the heartbeat and you may need further treatment for atrial fibrillation.
If you are fitted with an ICD, you are very likely to be on one or more of these drugs.
Anticoagulants. Heparin. Warfarin.
Anticoagulants prevent fibrin from forming within arteries or veins so reducing the risk of clots. Heparin is injected into the vein particularly when deep-vein thrombosis is suspected. Warfarin is prescribed for the longer-term prevention of clotting for instance for patients with disease of heart valves or serious arrhythmia. These drugs do effect bleeding so you will be given regular checks and must avoid excessive alcohol. It is important to always check, if you are going onto a new drug for another condition, because anticoagulant drugs interact with many other medicines.
Aspirin is a milder anti-coagulant.
Anti-cholesterol. Simvastatin, Pravastatin, Atrovastatin
Cipofibrate.
Ezetimibe.
Statins have been proved to be very effective in reducing the amount of blood lipids (the fatty things) in the blood stream. If untreated, these can accumulate in the arteries so narrowing them or even causing a blockage. Statins should be taken late in the evening to be most effective. Cipofibrate is an older drug which works by combining the bile acids with the fibrates so reducing the cholesterol. Ezetimibe is a much newer drug still under some testing. This works by preventing the cholesterol from being absorbed in the small intestine.
Summary of drugs to treat:
I say again that most patients will be prescribed a cocktail of drugs to treat one or more of these conditions.
Angina and/or high blood pressure. ß-blockers, calcium channel blockers, potassium channel activators, nitrates, ACE inhibitors, antiogensin II antagonists, anti-coagulants, diuretics
After angioplasty and a stent(s). Aspirin, clopidogrel, anti-coagulants.
Sudden heart attack. Clotbusters. Aspirin.
Removal of water and salt. Diuretics.
Atrial fibrillation. Digoxin.
Arrhythmia. Amiodarone, digoxin
Danger of clotting/thrombosis. Heparin, warfarin, aspirin.
Excessive cholesterol or triglycerides. Statins, cipofibrate.
GCS/24.05.10
Geoff Shaw.