ACE inhibitors and angiotensin II receptor blockers

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

How do ACE inhibitors and ARBs work?

There are systems in your body that work together to keep your blood pressure at a level 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 on your kidney 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 I meets 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 relaxed and the hormone aldosterone isn't released, so your blood pressure can be kept low.

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 a day.

Many people with high blood pressure or heart problems need to take more than one medicine. ACE inhibitors may be prescribed 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 are African-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 be unsuitable if you have a problem with the arteries that supply your kidneys (renal artery stenosis). This is because they may affect the way your kidneys work. Also, if you have heart failure and your kidneys are affected as a result, ACE inhibitors and ARBs may not be suitable. However, if it's best to take these medicines, your doctor may ask you to have a blood test before you start them and then again in the first month of treatment. 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. Other side-effects include:

  • tiredness
  • headache
  • dizziness
  • skin rashes
  • hay fever-like symptoms (sneezing, blocked or runny nose, itchy eyes)
  • swelling of your sinuses (sinusitis)
  • sore throat
  • a persistent dry cough
  • feeling sick or vomiting
  • indigestion
  • diarrhoea or constipation

In general, ARBs cause fewer side-effects than ACE inhibitors. If you have side-effects, it's important to talk to your doctor or the healthcare professional who prescribed your medicine before you stop taking it.

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). Check with your doctor or pharmacist before you take any other medicines or herbal remedies at the same time as ACE inhibitors or ARBs.

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*, Lisicostad*, Zestoretic*
moexipril Perdix
perindopril Perindopril
quinapril Accupro, Accuretic*
ramipril Tritace, Triapin**
trandolapril Gopten, Tarka**
Angiotensin II receptor blockers  
candesartan Amias
eprosartan Teveten
irbesartan Aprovel, CoAprovel*
losartan Cozaar, Cozaar-Comp*
olmesartan Olmetec, Olmetec Plus*, Sevikar**
telmisartan Micardis, Micardis Plus*
valsartan Diovan, Co-Diovan*

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

Why does my age affect whether I am prescribed an angiotensin-converting enzyme (ACE) inhibitor?


ACE inhibitors may not be as effective at reducing blood pressure in people over the age of 55 compared to people who are younger. So if you are aged 55 or over, your doctor will try to control your blood pressure with another type of medicine first.


ACE inhibitors seem to be better at lowering blood pressure in younger people. This is thought to be because younger people with high blood pressure may have a higher level of a chemical called renin in their bodies. Your body needs renin to make angiotensin I – which is converted into angiotensin II. It is the effects of angiotensin II that raise your blood pressure.

Medicines such as ACE inhibitors that affect the renin-angiotensin system are therefore thought to have a better effect in younger people.

ACE inhibitors are also not as effective at lowering blood pressure in African-Caribbean people, because people in this ethnic group tend to have lower levels of renin than Caucasian people, for example.

If you have high blood pressure and are over 55 or are African-Caribbean, your doctor will usually prescribe a diuretic or a calcium-channel blocker first to try to control your blood pressure. If you don't respond to this medicine, he or she may then also prescribe an ACE inhibitor.

How do ACE inhibitors help people with diabetes?


If you have diabetes, ACE inhibitors help to protect your kidneys from becoming damaged as a result of your condition.


If you have diabetes, you are at higher risk of getting kidney disease. This is because the high levels of glucose associated with diabetes can damage the small blood vessels in your kidneys.

High blood pressure can cause further damage to your kidneys. So if you have diabetes, it is especially important to keep your blood pressure under control. ACE inhibitors are recommended to control blood pressure in people with diabetes, as they seem to offer better protection against kidney disease than other medicines for high blood pressure.

If you have diabetes, your doctor will prescribe an ACE inhibitor or an angiotensin II receptor blocker if tests show you have early signs of kidney disease or high blood pressure.

Can I drink alcohol when I’m taking ACE inhibitors or angiotensin II receptor blockers (ARBs)?


If you've been prescribed an ACE inhibitor or an ARB, you should always check with your doctor whether it is safe for your to drink alcohol and how much.


ACE inhibitors and ARBs are mainly used to treat high blood pressure. These medicines block the actions of chemicals released by your kidneys that work to increase your blood pressure. Alcohol relaxes your blood vessels and slows your heart rate.

If you are taking ACE inhibitors or ARBs, alcohol can enhance the effects and lower your blood pressure too much. Low blood pressure is a common side-effect in people taking ACE inhibitors and ARBs and drinking alcohol makes it even more likely to happen.

You may feel dizzy, light-headed and your blood pressure may drop to a point where you faint or have a heart attack.

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

Do angiotensin II receptor blockers (ARBs) increase your risk of cancer?


No, ARBs don't increase your risk of cancer.


In 2010, a study published in the Lancet Oncology suggested that people taking ARBs had a slightly increased risk of cancer compared to those not taking the medicine. The researchers had looked at information from five clinical trials.

In response, the US Food and Drug Administration (FDA) carried out a safety review of ARBs. The FDA looked at 31 randomized clinical trials, evaluating data from a total of over 84,000 people taking ARBs. The FDA found no evidence to suggest ARBs increased the risk of cancer.

If you're taking ARBs and have any concerns, it's important to talk to your doctor or the healthcare professional who prescribed your medicine before you stop taking it.