Treatments
You may be having planned or emergency treatment. We explain what to expect, how it will help and what will happen afterwards.
About ACE inhibitors
What are ACE inhibitors?
Angiotensin-converting enzyme (ACE) inhibitors are medicines that help your blood vessels to widen and relax. This helps lower your blood pressure and improves blood flow.
You may be given an ACE inhibitor if you have:
You may also be given other medicines to take for your condition, such as a calcium channel blocker and a diuretic.
ACE inhibitors may not be suitable for you if you’re over 55 or of African or Caribbean descent. There are other medicines that may be more effective for you. Speak to your doctor about your treatment options if this applies to you.
How do ACE inhibitors work?
ACE inhibitors stop your body from producing a hormone called angiotensin II.
This hormone increases your blood pressure by:
Making your blood vessels contract so they become narrower and your blood has less space to move.
Making your body hold onto more water in your blood which puts pressure on your blood vessels.
By reducing the hormone, ACE inhibitors make your blood vessels widen and relax. They also help remove extra fluid from your blood. This lowers your blood pressure and improves blood flow to your heart.
Video: How do ACE inhibitors work?
Types of ACE inhibitors
What are the different types of ACE inhibitors?
There are different types of ACE inhibitors. Some common types include:
- ramipril
- captopril
- enalapril
- lisinopril
- perindopril.
Find out more about these medicines on the NHS website.
The main difference between ACE inhibitors is how long their effects last. Some are short-acting and others are long-acting. For example, perindopril is long-acting and only needs to be taken once a day. Captopril is short-acting and needs to be taken 3 times a day.
You will usually be given a low-strength medicine first and your dose will be increased if it’s needed.
Side effects
What are the side effects of ACE inhibitors?
All medicines have potential side effects, but most people will not experience side effects.
Side effects of ACE inhibitors may include:
- dry cough
- dizziness
- headache
- swelling around the mouth, face or throat
- feeling more tired than usual (fatigue)
- weakness
- low sodium and high potassium (electrolyte imbalance).
Different medicines have different side effects. If you’ve started taking ACE inhibitors recently it’s worth bearing in mind that symptoms with any new medicine may improve over time or even disappear.
You’ll have your blood pressure tested regularly while taking an ACE inhibitor. You should also have a regular blood test. This checks how your kidneys are working and your electrolyte levels.
When should I get help?
Talk to your doctor if you’re having side effects. They can help you manage them or look at other options with you.
If you have side effects when taking an ACE inhibitor, your doctor may prescribe a different type of medicine called an angiotensin-II receptor blocker (ARB).
It’s important not to stop taking your medicine without speaking to a healthcare professional first.
How and when to take them
How do I take this medicine?
Most people will take an ACE inhibitor once a day. Try and take it at the same time every day.
How often you take your medicine will depend on the type of ACE inhibitor you’ve been prescribed and the dose.
Your doctor will give you more information about the type of ACE inhibitor they’re giving you and how often you should take it.
If you forget to take your medicine and:
- It's only a short time after your usual dose, take it as soon as you remember. Then take your next dose at the usual time.
- It’s nearly time for your next dose, do not take the one you missed. Wait and take your next dose at the usual time.
How long do I take it for?
Most people with high blood pressure will need to take medicines to lower their blood pressure long-term.
You will need to check your blood pressure regularly to make sure it’s under control. If your blood pressure is not under control, speak to your doctor. They may recommend increasing the dose of your medicine or trying an alternative or additional medicine.
It’s important not to stop taking your medicine without speaking to a healthcare professional first.
Things to avoid if you’re taking ACE inhibitors
It’s important to check with your doctor or pharmacist before taking any other medicine while you’re taking ACE inhibitors.
There are certain foods and over-the-counter medicines you may need to limit or avoid if you’re taking an ACE inhibitor. This is because they can stop your medicine from working properly.
This includes:
- foods high in salt
- NSAID medicines, like ibuprofen and naproxen
- medicines high in sodium, such as indigestion remedies like Gaviscon and cystitis medicines like CanesOasis.
You should not take ACE inhibitors if you’re pregnant. If you’re currently taking ACE inhibitors and you’re planning to get pregnant or you become pregnant, speak to your doctor.
Get help with ACE inhibitors
- Our cardiac nurses can help answer your questions on ACE inhibitors. Call, email or live chat with them on our Heart Helpline.
- Check if you can get free prescriptions or help paying for your prescriptions.
- Talk to other people with high blood pressure and get support in our online community.
You can trust our health information
We've followed an eight-step process to make sure this content is reliable, accurate and trustworthy.
Learn how we make our health content.
Understanding high blood pressure
This booklet can help you and your loved ones understand what high blood pressure is and how to make healthier changes to look after your heart health.
Your blood pressure chart and diary
If you want to measure your blood pressure at home, this blood pressure chart can help you understand what your reading means.