ACE inhibitors and angiotensin II receptor blockers

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (sometimes called ARBs or A2RBs) are medicines that lower blood pressure. They are used to treat high blood pressure and heart failure and to protect your kidneys from damage if you have diabetes.

Why would I take ACE inhibitors and ARBs?
How do ACE inhibitors and ARBs work?
How to take ACE inhibitors and ARBs
Special care
Side-effects of ACE inhibitors and ARBs
Interactions of ACE inhibitors and ARBs with other medicines
Names of common ACE inhibitors and ARBs

Why would I take ACE inhibitors and ARBs?

Your doctor may recommend ACE inhibitors or ARBs if you have:

• high blood pressure
• heart failure
• diabetes
• had a heart attack

How do ACE inhibitors and ARBs work?

There are systems in your body that work together to keep your blood pressure at the level that is normal for you. This will be a pressure that is high enough to get enough oxygen and nutrients around your body, but not so high that your blood vessels or organs get damaged. ACE inhibitors and ARBs lower your blood pressure by affecting these systems.

Sensors on your kidney can detect when your blood pressure drops too low. When this happens, a hormone called angiotensin I is released into your blood. On its own, angiotensin I doesn't have much effect. But when angiotensin I meets angiotensin-converting enzyme (ACE) in the blood, it is converted into angiotensin II.

Angiotensin II can raise your blood pressure in two ways.

• Firstly, it narrows your blood vessels – causing the pressure of the blood inside them to go up (a bit like squeezing a hose pipe).
• Secondly, it triggers the release of another hormone called aldosterone. This tells your body to hold on to water, rather than getting rid of it in your urine. The extra water stays in your blood, increasing the volume of blood in your body. Your blood pressure increases because there is a larger amount of blood squeezed into the same space.

ACE inhibitors block the action of ACE so that angiotensin I is not converted to angiotensin II. So ACE inhibitors relax the walls of your blood vessels and lower your blood pressure.

ARBs interfere with the action of angiotensin II on blood vessels and also lower your blood pressure.

How to take ACE inhibitors and ARBs

ACE inhibitors and ARBs are only available on prescription. They usually come as tablets, which you will usually need to take once a day, as your doctor advises you.

Many people with high blood pressure or heart problems need to take more than one medicine. Your doctor may recommend that you take an ACE inhibitor in combination with other heart and blood pressure medicines, such as diuretics (water tablets).

Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Special care

Your doctor may not prescribe ACE inhibitors or ARBs if you’re pregnant or breastfeeding. Both medicines may also be unsuitable if you have a problem with the arteries that supply your kidneys (renal artery stenosis). If you are African-Caribbean, ARBs may not work so for you, so your doctor may give you a different medicine.
 

Side-effects of ACE inhibitors and ARBs

This section does not include every possible side-effect of ACE inhibitors and ARBs.  Read the patient information leaflet that comes with your medicine for more information.

ACE inhibitors and ARBs can sometimes cause your blood pressure to fall, which may make you feel dizzy when you stand up. So, after taking a dose, get up slowly from lying or sitting down and stay next to your chair or bed until you’re sure that you’re not feeling dizzy. Dizziness can often be expected with some ACE inhibitors and ARBs, but your blood pressure will usually settle. If you continue to experience dizziness, see your GP for advice.

The most common side-effect of ACE inhibitors is a long-lasting dry cough. Other, less common, side-effects of ACE inhibitors are:

• skin rash
• hayfever-like symptoms (sneezing, blocked or runny nose, itchy eyes)
• swelling of your sinuses (sinusitis)
• sore throat
• feeling sick or vomiting
• indigestion
• diarrhoea or constipation

In general, ARBs cause fewer side-effects than ACE inhibitors, and do not cause a dry cough. Side-effects include feeling dizzy.

It's important to weigh up the low risk of side-effects with the good chance that your health will benefit from taking these medicines.

Interactions of ACE inhibitors and ARBs with other medicines

Check with your doctor or pharmacist before you take any other medicines or herbal remedies at the same time as an ACE inhibitor or an ARB.

Names of common ACE inhibitors and ARBs

The main types of ACE inhibitors and ARBs are shown in the table.

All medicines have a generic name. Many medicines also have one or more brand name. Generic names are written in lower case, whereas brand names start with a capital letter.

This information was published by Bupa’s health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.

Publication date: September 2009.