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ACE inhibitors and angiotensin II receptor blockers

Key facts

  • Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are mainly used to treat high blood pressure (hypertension) and heart failure.
  • They work by widening (dilating) blood vessels and enhancing the kidneys’ excretion of salt and water.
  • Your doctor may not prescribe ACE inhibitors or ARBs if you're pregnant or breastfeeding, or if you have problems with your kidneys.

Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are mainly used to treat high blood pressure (hypertension) and heart failure. They can also reduce the risk of kidney damage in people with diabetes.

Why would I take ACE inhibitors and ARBs?

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

  • high blood pressure
  • heart failure or have had a heart attack
  • diabetes, and there are signs of kidney problems

How do ACE inhibitors and ARBs work?

There are systems in your body that work together to keep your blood pressure high enough to get enough oxygen and nutrients around your body. ACE inhibitors and ARBs lower your blood pressure by acting on one of these systems; the renin-angiotensin-aldosterone system.

Sensors in your kidneys can detect when your blood pressure drops too low. When this happens, a chemical called angiotensin I is released into your blood. On its own, angiotensin I doesn't have much effect. But when angiotensin reacts with angiotensin-converting enzyme in the blood, it is converted into angiotensin II.

Angiotensin II narrows your blood vessels. It also acts on the adrenal glands to trigger the release of aldosterone. Aldosterone makes your body hold on to water. The extra volume of fluid in your blood and the narrowing of the blood vessels cause your blood pressure to rise. ACE inhibitors and ARBs work on these systems to act in the following ways.

  • ACE inhibitors block the action of ACE so that angiotensin I isn't converted to angiotensin II.
  • ARBs block the action of angiotensin II by stopping it from interacting with your blood vessels and adrenal glands.

Without angiotensin II, your blood vessels remain more relaxed and the hormone aldosterone isn't released, so your blood pressure is lowered.

How to take ACE inhibitors and ARBs

ACE inhibitors and ARBs are only available on prescription from a doctor. They usually come as tablets, which you take once or twice a day.

Many people with high blood pressure or heart problems need to take more than one medicine. Your doctor may prescribe ACE inhibitors in combination with other medicines, such as a diuretic or a calcium-channel blocker.

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. If you’re African or Caribbean and have high blood pressure, ARBs may not work so well for you. So your doctor may give you a different medicine.

ACE inhibitors and ARBs may not be suitable if you have a narrowing of the arteries that supply your kidneys (renal artery stenosis). This is because they may affect the way your kidneys work. Your doctor may ask you to have a blood test before you start them and further tests while you’re taking them. This is to check how well your kidneys are working.

Side-effects of ACE inhibitors and ARBs

Side-effects are the unwanted effects of taking a medicine. This section does not include every possible side-effect of ACE inhibitors and ARBs. Please read the patient information leaflet that comes with your medicine for more information.

The most common side-effects of ACE inhibitors and ARBs are low blood pressure and a reduction in kidney function. You may also have a persistent dry cough with ACE inhibitors (but not commonly with ARBs).

Other side-effects include:

  • tiredness
  • headache
  • dizziness
  • skin rashes
  • cold-like symptoms
  • feeling sick or vomiting
  • indigestion
  • diarrhoea or constipation

In general, ARBs cause fewer side-effects than ACE inhibitors. Your doctor may offer ARBs if you get a cough or other side-effects with ACE inhibitors. If you have side-effects, talk to your doctor or the healthcare professional who prescribed your medicine.

Interactions of ACE inhibitors and ARBs with other medicines

Some medicines can enhance the effects of ACE inhibitors and ARBs, resulting in very low blood pressure (hypotension). Other medicines that cause a rise in the potassium level in the blood can also cause problems if taken together with ACE inhibitors and ARBs. Check with your doctor or pharmacist before taking any other medicines.

You may find herbal remedies helpful but it's important to remember that natural doesn't mean harmless. Herbal remedies contain active ingredients and may interact with other medicines or cause side-effects. Don't start taking any herbal remedies without speaking to your doctor or pharmacist first.

Names of common ACE inhibitors and ARBs

All medicines have a generic name. Many medicines also have one or more brand name. Generic names are in lower case, whereas brand names start with a capital letter. The main types of ACE inhibitors and ARBs are shown in the table.

Generic names Examples of common brand names
ACE inhibitors  
captopril Capoten, Capozide*
cilazapril Vascase
enalapril Innovace, Innozide*
imidapril Tanatril
lisinopril Zestril, Carace Plus*, Zestoretic*
moexipril Perdix
perindopril erbumine Perindopril
perindopril arginine Conversyl Arginine, Conversyl Arginine Plus*
quinapril Accupro, Accuretic*
ramipril Tritace, Triapin**
trandolapril Gopten, Tarka**
Angiotensin II receptor blockers  
azilsartan Edarbi
candesartan Amias
eprosartan Teveten
irbesartan Aprovel, CoAprovel*
losartan Cozaar, Cozaar-Comp*
olmesartan Olmetec, Olmetec Plus*, Sevikar**, Sevikar HCT ***
telmisartan Micardis, Micardis Plus*
valsartan Diovan, Co-Diovan*, Exforge**

*with a diuretic; ** with calcium-channel blocker, *** with calcium-channel blocker and diuretic

Reviewed by Dylan Merkett, Bupa Health Information Team, January 2014.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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