ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are a class of antihypertensive drugs which prevent the hormone angiotensin II from being produced - a hormone which typically narrows the blood vessels. They lower blood pressure in the body by relaxing the blood vessels. 

  1. Taken between once and three times a day
  2. First-line treatment for people under 55 years old
  3. Branded under many names, including Capoten, Prinivil, Zestril, Coversyl or Coversum

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Product information

What are ACE inhibitors?

ACE inhibitors tend to be used to treat conditions such as high blood pressure, heart failure (or for people who have had a heart attack), diabetes or kidney disease. They lower blood pressure in the body by relaxing the blood vessels.  

Heart failure

Heart failure (or congestive heart failure) occurs when the heart is incapable of pumping blood around the body sufficiently. This is usually because the heart has become either too fragile or too stiff. It isn’t indicative of the heart no longer functioning; it just means that the heart requires some assistance to improve its performance. 

Anyone can be affected by heart failure, regardless of age, but it’s more prevalent amongst older people. Breathlessness following activity or when at rest, lethargy and tiredness when exercising, and swollen ankles and legs are common symptoms. 

There are a number of tests that may be conducted to diagnose heart failure. Blood tests can identify if there’s any indication of heart failure or illness in the blood, while an electrocardiogram (ECG) measures the electrical functioning of the heart for issues. An echocardiogram (or “echo”) is an ultrasound scan which utilises sound waves to monitor the heart. 

To ascertain if a lung problem is a factor in your breathlessness, a doctor may request that you blow into a tube (spirometry or a peak flow test). A chest X-ray can also form part of your assessment, to establish if the heart is larger than it should be, whether fluid has accumulated in the lungs or if a lung condition is leading to symptoms.   


Diabetes is a condition that affects people on a lifelong basis, and causes blood sugar levels to become too elevated. There are two major types: type 1, in which the body’s immune system kills the cells that create insulin, and type 2, which manifests when the body doesn’t produce a sufficient amount of insulin, or when the body’s cells don’t respond to insulin. type 2 diabetes is much more common than type 1, accounting for 90% of all adult diabetics.

In terms of symptoms, major signs of diabetes include extreme thirst, urinating more often than you would typically (particularly at night), pronounced fatigue, weight and muscle loss, itching around the genitals, recurring bouts of thrush, cuts and wounds that take longer to heal, and blurred vision. 

A diagnosis for diabetes is usually established via a urine test by your GP and a blood test to assess your blood sugar levels. 

Kidney disease

Kidney disease occurs when the kidneys can’t filter blood properly, and therefore aren’t functioning as effectively as they should. It can affect anyone, but it’s more significant amongst people of black or South Asian descent. Having diabetes or high blood pressure puts you at greater risk of developing kidney disease, and ACE inhibitors can offer some protection against kidney disease for people with diabetes.

Initially, it doesn’t tend to present any symptoms, but it can be identified by a GP at a more advanced stage if you feel tired, have swollen feet or ankles, experience shortness of breath, feel sick or if there’s blood in your urine. Blood and urine tests, to establish if there are excessive amounts of particular substances in your blood and urine, are used for a diagnosis. These tests can also determine the severity of the damage to your kidneys.

How are ACE inhibitors prescribed?  

ACE inhibitors are a first line treatment for patients under 55 with high blood pressure. If you’re over 55, or of African or Caribbean origin, a calcium channel-blocker is the go-to, first-time, alternative form of treatment. 

Typically, ACE inhibitors are taken on an extended basis, with close monitoring from your GP annually.

What ACE inhibitors are available?

There are a number of specific, ACE inhibitor products available, and the main distinguishing factor is how long their effects persist for. Some inhibitors, such as captopril (branded as Capoten), are short-acting, while others, such as lisinopril (branded as Prinivil or Zestril) or perindopril (branded as Coversyl or Coversum), are long-acting. 

The required dosage of ACE products is determined by how long the product is active in the body. Perindopril for instance only needs to be taken once a day, whereas captopril should be taken three times a day. ACE products are available in numerous strengths, with a lower dose usually recommended at the start of treatment. 

You can use our online video consultation service to speak to one of our GPhC-registered clinicians about ACE inhibitors from 9:30am to 4:30pm, five days a week.

Page last reviewed:  18/06/2020
Side effects and warnings

What side effects do ACE inhibitors have?

One of the more common side effects of using ACE inhibitors is a dry, tickly cough. Approximately one in 10 people experience this, and you should contact your doctor about it as soon as you can. Should your GP prescribe you with an alternative treatment, you should note that it may take between eight and 12 weeks for the cough to disappear.

Less commonly (fewer than 1 in 100 people) ACE inhibitors can cause an issue with the blood supply to the kidneys, known as renal stenosis. There are no apparent symptoms, and as such, you should arrange to have a routine blood test to determine your kidney function one to two weeks after starting the treatment course.

Rare side effects (affecting around 1% of people) usually consist of swollen lips and breathing problems. They can develop anytime between the first two weeks and two years of starting to take ACE medication. In these circumstances, your GP will stop your treatment and may prescribe an angiotensin receptor blocker (ARB) as an alternative.

Can you take ACE inhibitors with other medicines?

Yes. ACE inhibitors are frequently prescribed alongside other treatments, and this is known as the synergistic effect. ACE inhibitors work efficiently with a type of drug called diuretics (drugs that enable you to pass water) and also with calcium channel blockers. 

When used in conjunction with diuretics, ACE inhibitors’ effectiveness at lowering blood pressure and regulating heart failure is bolstered. The likelihood of developing swollen ankles as a side effect is also reduced.

It is worth noting that the combination of an ACE inhibitor and a diuretic can in some cases result in a sudden decrease in blood pressure. If you experience any dizziness or nausea, you should contact your GP.

Who shouldn’t take ACE inhibitors?

ACE inhibitors are not recommended for women who are pregnant, or for women who are trying to become pregnant. 

People who have severe or advanced kidney disease shouldn’t take ACE inhibitors (even though they can offer protection for people at risk of kidney disease). People who have a narrowing of the aorta should also avoid them.

Can you take ACE inhibitors if you are pregnant or breastfeeding?

Women who are pregnant are advised not to use ACE inhibitors, and they’re unsuitable for women who are breastfeeding within the first few weeks following delivery.

Yes. ACE inhibitors are frequently prescribed alongside other treatments, and this is known as the synergistic effect. ACE inhibitors work efficiently with a type of drug called diuretics (drugs that enable you to pass water) and also with calcium channel blockers. 

Page last reviewed:  18/06/2020
Questions and Answers

What are some examples of ACE inhibitors?

Common examples of ACE inhibitors are captopril (branded as Capoten), lisinopril (branded as Prinivil or Zestril) or perindopril (branded as Coversyl or Coversum).

Can I still drink alcohol and take ACE inhibitors?

You should not use ACE inhibitors without having discussed the risks with a doctor first. If they are taken in combination with alcohol, it can result in your blood pressure becoming lower than it should be, causing dizziness and potentially fainting. 

Will I still be able to drive when taking ACE inhibitors?

ACE inhibitors should be used with caution when driving, operating machinery, or when engaging in any other hazardous activity. If you experience any feelings of dizziness or drowsiness, refrain from these activities.

Can you be allergic to ACE inhibitors?

Some ACE inhibitors, such as lisinopril, perindopril, enalapril and ramipril, can cause angioedema, as a consequence of an allergic reaction to the treatment. Angioedema results in swelling of the skin, hives and less commonly symptoms such as conjunctivitis. 

Can you get ACE inhibitors over-the-counter?

No. ACE inhibitors are only available on prescription.

Can I buy ACE inhibitors online?

You can speak to one of our GMC-registered clinicians about ACE inhibitors using our online video consultation service. They’re available between 9:30am and 4:30pm, five days a week. 

Page last reviewed:  18/06/2020

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