ACE Inhibitors

ACE inhibitors are a commonly used type of high blood pressure medication. They are called ACE inhibitors because they stop an enzyme in your kidneys from producing a hormone called angiotensin-II.

Angiotensin-II increases your blood pressure by making your artery walls contract. This narrows the arteries and gives your blood less space to move in – raising your blood pressure. ACE inhibitors reduce the amount of angiotensin-II your kidneys make, allowing your arteries to stay more open and reducing your blood pressure.

Angiotensin-II also stimulates your adrenal glands to produce a hormone that makes the body retain water. This increases the amount of fluid in your body and raises your blood pressure. ACE inhibitors also reduce the amount of hormone your adrenal glands produce, which lowers the amount of water you retain and helps to lower your blood pressure.

Who should take ACE inhibitors?

ACE inhibitors should are often used as a first choice of treatment for people aged younger than 55 years old who are white or Asian. These people appear to have higher levels of angiotensin-II in their bloodstream. This means that their blood pressure is influenced more strongly by the effects of this hormone, so any medicine that reduces its effect will be most powerful.

ACE inhibitors are often given as the first choice of treatment for people with diabetes and high blood pressure because the medicines appear to have additional beneficial effects. It has been found that they can protect the kidneys of people with diabetes. They also appear to delay damage to the retina, which can impair the eyesight of people with diabetes.

ACE inhibitors may also be given to some who have:

• had a heart attack
• an enlarged left side of the heart
• heart failure.

Who should not take ACE inhibitors?

If you are already taking a diuretic, you can take ACE inhibitors but you should have your blood pressure regularly checked by your doctor at first. This is because the first time you take this medicine you may have a sudden fall in blood pressure, which could be made worse by the diuretic.

ACE inhibitors should not be taken if you are pregnant, trying to become pregnant, or breastfeeding, because they may affect your baby's development. Instead your doctor will prescribe one of the other types of blood pressure drug that will not cause any unwanted effects to the baby.

ACE inhibitors are also normally avoided if you have kidney disease, although your specialist may prescribe them in certain circumstances. The same is the case if you have peripheral artery disease (PAD).

What are the most common side-effects of ACE inhibitors?

On the whole, ACE inhibitors do not tend to cause people too many problems, but some side-effects can occur: 

Dry cough: roughly 10% of men and 20% of women who take an ACE inhibitor develop a dry cough. It is not harmful, but it can be very irritating and uncomfortable.

Changes to your sense of taste: occasionally, some people find that their sense of taste is disturbed by taking an ACE inhibitor.

Acute allergy: very rarely, some people who are taking an ACE inhibitor develop swelling around the mouth or face. About one in 1,000 black people and one in 4,000 white or Asian people develop this allergic reaction. If the allergy affects your throat it could make breathing or swallowing difficult – if this happens, go straight to your nearest Accident and Emergency Department or dial 999.

Other problems: other side-effects that may occur include problems with the kidneys and (occasionally) a rash.

If you develop side-effects from your medications, your doctor may be able to help by lowering your dose, or by changing your medicine. Often, people who cannot tolerate ACE inhibitors are given a medication called an angiotensin receptor blocker, which works in a similar way to an ACE inhibitor but which does not tend to have the same side-effects.

Do not stop taking any medicine without first speaking to your doctor.

Types of ACE inhibitor

Most medications have two names – the generic name (which is the name of the medicine itself) and the brand name (which is the name the medicine is sold under). This means different companies may make and sell the same medicine, but they may sell it with different brand names. The table below lists some ACE inhibitor medicines currently used in the UK: