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ACE INHIBITORS

What are the types of ACE Inhibitors?

They are all very similar substances which can usually be identified by their ending: "...pril": captopril (Capoten), enalapril (Innovace), lisinopril (Zestril, Carace), perindopril (Coversyl), ramipril (Tritace), quinapril (Accupro), cilazapril (Vascace), trandolapril (Gopten, Odrik).

What are ACE Inhibitors for ?

ACE inhibitors are used mainly to treat high blood pressure or heart failure. When used for high blood pressure they may be used alone, or sometimes combined with other drugs such as beta-blockers (23.4) calcium channel blockers (23.3) or water tablets (diuretics 23.1). A raised blood pressure must be lowered to reduce the risk of strokes, heart attacks and kidney damage. When your heart cannot pump strongly enough to get blood through to all the parts of your body, ACE inhibitors are now often used, again either alone, or in combination with other drugs. ACE inhibitors are also used in some people with diabetes. They help to reduce the risk of kidney damage in later life.

How do ACE Inhibitors work ?

ACE inhibitors work by stopping the action of a chemical in the blood called angiotensin converting enzyme (ACE). As a result of this, the blood-vessels all over the body become wider, and blood can flow through them more readily. This makes it easier for the heart to work. If your heart is already under strain, it will have less work to do and you will feel better. Blood pressure is mostly raised because the blood-vessels are narrow: the wider blood-vessels allow the blood pressure to fall.

How should ACE Inhibitors be used ?

You should take your ACE inhibitor regularly, every day, whether you feel you need it or not. Most are taken just once a day, but some need to be taken twice or three times a day, because they only work for a shorter time. Check the label! It is likely that you will be started on a low dose to start off with. Some people get quite a sudden drop of blood pressure with their first dose in any case, causing dizziness or even a faint. Your dose will be gradually increased, every few days or weeks, until the desired effect is obtained. Your doctor may tell you to stop taking other blood pressure-lowering drugs, especially diuretics, 2 to 3 days before you start taking your ACE inhibitor. This is because the blood pressure could fall even more when combined with a diuretic. For this reason also, it is safer to take the first dose of ACE inhibitor at bed-time, lying in bed. If you have heart failure, stopping a diuretic may not be advisable. Your doctor may suggest that you are admitted to hospital. Your ACE inhibitor can then be started safely, under supervision, without having to stop your diuretic. Lying in bed while the first few doses take effect reduces the risk of fainting. Once you are used to the drug, your doctor may increase the dose again later, either if your blood pressure is not down to normal, or if your heart failure is not quite controlled.

During Treatment with ACE Inhibitors …

It is wise to avoid driving or operating dangerous machinery until you know you will not feel dizzy. If dizziness persists, do see your doctor. You may need to cut back the dose. If you are taking an ACE inhibitor for heart failure, you should soon start to feel less breathless. It may take a few weeks of adjusting the dose before you feel the full benefit. If you are taking the ACE inhibitor for high blood pressure, you will probably not feel any improvement in your health. You cannot feel whether your blood pressure is high or normal. Only measuring the pressure can tell if it is controlled. Quite often, the drug can cause a dry, irritating cough which does not get better. Reducing the dose sometimes helps. Voice changes, a sore throat or mouth ulcers can also occur. If any of these happen to you, you should tell your doctor promptly. You may get a rash soon after starting the drug. Usually this does not last very long and will disappear as you continue treatment. You should tell your doctor if you have a fever or joint or muscle pain with the rash. This may mean that you are allergic to ACE inhibitors. ACE inhibitors tend to make the level of potassium in your blood rise. If the level gets too high it can affect the heartbeat. For this reason, a blood test for this will be taken from time to time, particularly if there has been a change in your other drugs. Some people get stomach or bowel upsets. If these are a continuing problem, your doctor should be told. They can also cause some loss of taste or appetite. This is common and no cause for worry.

Drug Interference …

The effect of ACE inhibitors on blood potassium levels is made worse by certain diuretics. Your doctor will take care not to give you one that has this effect. You will probably be advised to stop any potassium containing tablets. Some salt substitutes also contain potassium and should be stopped. Alcohol as well as some tablets used for heart and blood pressure problems (calcium channel blockers and nitrates) can make your blood pressure fall too low. Anti-inflammatory painkillers (NSAIDs) can reduce the effect of ACE inhibitors. At the same time they run the risk of damaging your kidneys. Please tell your doctor about any other medicines you are taking, before he or she prescribes an ACE inhibitor.

What if ACE Inhibitors are not taken ?

If you forget to take a dose of your ACE inhibitor at the usual time, take it as soon as you remember. You should not stop taking your ACE inhibitor unless your doctor tells you to. Your heart failure or blood pressure problem would get worse, with a risk of stroke or heart attack.

General advice about ACE Inhibitors

ACE inhibitors may not be suitable for you if you have certain kidney problems. Please tell your doctor if you are, or could be pregnant, or if you want to become pregnant while you are taking an ACE inhibitor. They can affect the baby's kidneys and blood pressure control if taken at any time during pregnancy. If you have any questions not covered in this leaflet, please ask your pharmacist or doctor: Keep this leaflet handy in case you want to refer to it again.