ACE inhibitors

ACE inhibitors are angiotensin converting enzyme inhibitors. They may be used for high blood pressure, heart failure diabetic kidney disease, chronic kidney disease and after a heart attack (myocardial infarction).

On this page, you can find the following information:

Examples of ACE inhibitors

Most ACE inhibitors have names that end in ‘pril’. The following ACE inhibitors are available in Aotearoa New Zealand.

ACE inhibitors available in New Zealand

  • captopril (Capoten)
  • cilazapril (Zapril, Apo-Cilazapri)
  • enalapril (Enalapril Ethics, Renitec M)

ACE inhibitors are sometimes combined with a diuretic (water tablet), for example:

  • cilazapril + hydrochlorothiazide
  • quinapril + hydrochlorothiazide (Accuretic®).

When are ACE inhibitors used?

ACE inhibitors have many different effects on the body and are used to treat a variety of conditions. They may be used for:

  • High blood pressure by relaxing and widening your blood vessels and lowering your blood pressure.
  • Heart failure to help the heart pump blood more easily. This can help to relieve symptoms such as shortness of breath and swelling of feet, legs and abdomen (tummy/puku).
  • Diabetic kidney disease (diabetic nephropathy) to protect your kidneys and help them to function.
  • Chronic kidney disease to slow the progress of kidney disease.
  • After a heart attack (myocardial infarction) to protect your heart.

ACE inhibitors can work very quickly for high blood pressure (hypertension). However, if you have heart failure it may be a few weeks or months before you notice an improvement in your symptoms. Once you have started taking an ACE inhibitor you will generally keep taking it for life unless you have a side effect.

The following animation describes how ACE inhibitors work in your body.

 (British Heart Foundation, 2018)

Who cannot take ACE inhibitors?

If you are pregnant or planning a pregnancy

ACE inhibitors can affect your baby's kidneys, especially if it's taken in the second and third trimesters of pregnancy. This can result in long term damage to your baby's kidneys.

If you're already pregnant, talk to your doctor straight away. Usually your doctor will be able to prescribe a different medicine that is safe to take in pregnancy. ACE inhibitors should be stopped by the time you're 12 weeks pregnant at the latest.

Use contraception if you're taking ACE inhibitors and carefully plan any pregnancy with your GP, pregnancy specialist (obstetrician) or hospital doctor. They will want to review your medical condition and medicine before you get pregnant.

Most women stop taking ACE inhibitors before getting pregnant, but some may continue until they have a positive pregnancy test and then stop. Your doctor will discuss what's best for you, based on your medical condition and the risks and benefits of ACE inhibitors.

Severe allergic reaction

You shouldn't take ACE inhibitors if you've had a severe allergic reaction to an ACE inhibitor in the past, eg, swelling of your lips, eyes or tongue (called angioedema). Angioedema is a rare but potentially serious side effect and it can be fatal. It can occur at any time, including in people who have been taking ACE inhibitors for years.

Blood tests and monitoring

A blood test is usually done before starting an ACE inhibitor, and about 1 to 2 weeks after the first dose. You may also require further blood tests as your dose increases. These tests are done to check how well your kidneys are working and your sodium and potassium levels. The kidneys are affected in a small number of people who take an ACE inhibitor. While you are taking an ACE inhibitor you will need to have blood tests every few months.

Things to consider while you are taking ACE inhibitors

Have a sick day plan

If you have diarrhoea (runny poo) or are vomiting (being sick) from a stomach bug, or are dehydrated from another illness, it’s important to let your healthcare provider know, as they may advise you to stop taking your ACE inhibitor for a few days, or decrease the dose and start again when you feel better. The reason for this is that ACE inhibitors can increase the amount of potassium salts in your blood, particularly if you are dehydrated.

Be careful when taking some pain relief medicines

ACE inhibitors help to protect your kidneys from damage if you have diabetes. In most cases ACE inhibitors are not only safe, but they are also protective. However, if you are on an ACE inhibitor and take diuretics (water pills), the combination of these with NSAIDs (anti-inflammatory pain relief medication) can be very harmful to your kidneys. It can cause acute kidney injury. This combination is called the dangerous trio or triple whammy. You have a higher risk of harm to your kidneys if you are an older person or you're dehydrated. 

If you are taking an ACE inhibitor with a diuretic, do not use NSAIDs for pain relief. Ask your doctor or pharmacist for a safer option. Read more about NSAIDs and protecting your kidneys.

Examples of diuretics Examples of NSAIDs
  • bendrofluazide (Arrow-Bendrofluazide)
  • chlorthalidone (Hygroton)
  • indapamide (Dapa-Tabs, Napamide)
  • metolazone (Zaroxolyn)
  • furosemide (Diurin)
  • ibuprofen (Ibugesic, I-Profen, Nurofen)
  • diclofenac (Voltaren)
  • naproxen (Noflam, Naprosyn)
  • mefenamic acid (Ponstan)
  • celecoxib (Celebrex)

Other medicines

Let your doctor and pharmacist know about all the other medicines you are taking. Some medicines should not be taken together with ACE inhibitors or the dose needs to be adjusted. These medicines include lithium, some types of diuretics and some medicines used for diabetes.

What are the side effects of ACE inhibitors?

Like all medicines, ACE inhibitors can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine. Common side effects include headache and nausea (feeling sick) or vomiting (being sick). Some people may get a change in their taste, but this is rare. Other side effects to be aware of are dizziness, dry cough and allergic reaction.

Dizziness

Dizziness is quite common when you first start taking an ACE inhibitor, especially after the first few doses. Take special care as you are at increased risk of falls, especially when you stand up from sitting or lying down. Your doctor will start you on a low dose and slowly increase how much you take. When starting an ACE inhibitor, get up slowly out of bed or stand up slowly; take a few minutes to sit on your bed or on a chair first. The dizziness goes away after a while. If the dizziness is severe or ongoing, tell your doctor.

Dry cough

This is quite common with people taking an ACE inhibitor – it happens in about 1 in 10 people. Sometimes this even happens after you have been taking the medicine for months. If you have a dry cough and it's uncomfortable, talk to your doctor. They may change you to a different medicine. 

Allergic reaction

Rarely, people taking ACE inhibitors can develop an allergic reaction, which causes swelling of your face, eyes, mouth, lips, tongue, throat, or to your legs, feet or hands. Swelling is a sign of a condition called angioedema and it can be dangerous if it affects any part of your mouth or throat. This can happen any time from 2 weeks to 2 years after starting to take ACE inhibitors. If you have this kind of swelling in your face, mouth or throat, you should get medical attention right away.

Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

References

  1. Angiotensin-converting enzyme inhibitors NZ Formulary
  2. Safe and effective use of ACE inhibitors in primary care BPAC, NZ, 2012
  3. Guide for initiation and up-titration of ACE inhibitors for patients with heart failure SafeRx, 2017
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 29 Nov 2022