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Captopril - an ACE inhibitor

Captopril is used to treat a number of different conditions.

The first dose may make you feel dizzy, so it is best taken just before you go to bed.

Some painkillers and indigestion remedies interfere with captopril, so ask your pharmacist for advice before you buy any medicines.

Some people taking captopril develop a troublesome cough. If this happens to you, let your doctor know.

Clinical author's note: Michael Stewart 15/11/2018: following an MHRA update, new advice has been added to this leaflet for people also taking the blood pressure medicine hydrochlorothiazide. Hydrochlorothiazide is only available in the UK in combination with other blood pressure medicines such as captopril. It may be available on its own in other countries. For more information see 'Getting the most from your treatment' below or view the MHRA Alert.

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About captopril

Type of medicine

An angiotensin-converting enzyme (ACE) inhibitor

Used for

High blood pressure; heart failure; to help prevent kidney problems after a heart attack; to help prevent kidney problems associated with diabetes

Available as

Tablets and oral liquid medicine

Captopril belongs to a class of medicines called angiotensin-converting enzyme inhibitors, or ACE inhibitors. It is prescribed for a number of different reasons. You may have been prescribed it to reduce high blood pressure (hypertension), or to treat heart failure, or to protect your heart and blood vessels from further damage following a heart attack, or to protect your kidneys if you have diabetes. Your doctor will tell you why it has been prescribed for you.

ACE inhibitors like captopril prevent your body from creating a hormone known as angiotensin II. They do this by blocking (inhibiting) a chemical called angiotensin-converting enzyme. This widens your blood vessels and helps to reduce the amount of water put back into your blood by your kidneys.

These actions help to decrease blood pressure in people who have blood pressure which is higher than normal. Although people with high blood pressure often do not feel unwell, if left untreated, high blood pressure can harm the heart and damage blood vessels, leading to a heart attack or stroke.

Heart failure is a condition where your heart does not work as well as it should. Because of this, there may be too much circulating fluid in your blood vessels. Captopril helps to reduce this. It appears to have a protective effect on the heart and slows the progression of the heart failure. Its protective action also helps to reduce the risk of heart, kidney or blood vessel problems in people who are at risk of these.

Before taking captopril

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking captopril it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have problems with the way your kidneys work.

  • If you are lacking in fluid in the body (dehydrated) - for example, if you have had diarrhoea or sickness very recently.

  • If you have been told you have a build-up of fatty deposits on the walls of your arteries, a condition called atherosclerosis.

  • If you have a particular type of poor circulation called peripheral arterial disease.

  • If you have collagen vascular disease - this includes conditions such as systemic lupus erythematosus (SLE) and scleroderma.

  • If you have been told you have heart muscle disease (cardiomyopathy), or narrowing of the main blood vessel from your heart (aortic stenosis).

  • If you have ever had a reaction where your face, tongue or throat swells (angio-oedema).

  • If you are having desensitisation treatment to protect against bee and wasp stings.

  • If you are having dialysis treatment, or treatment to remove cholesterol from your blood by a machine (LDL apheresis).

  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic or unusual reaction to any other ACE inhibitor (such as lisinopril, ramipril or perindopril), or to any other medicine.

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How to take captopril

  • Before you start this treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about captopril and will provide you with a full list of side-effects which you may experience from taking it.

  • Take captopril exactly as your doctor tells you to. The dose you are prescribed will depend upon your condition - you could be asked to take one, two or three doses each day. The dose will be printed on the label of the pack to remind you what the doctor said to you.

  • Your doctor may advise you to take your very first dose at bedtime. This is because you may feel dizzy when you first start taking captopril.

  • After this first dose, you can generally take captopril at a time of day you find easy to remember (for most people, this is in the morning). If you are taking more than one dose a day, space your tablets out through the day, but do try to take them at the same times each day. This will help you to avoid missing any doses.

  • You can take captopril tablets before or after meals. Swallow the tablets with a drink of water.

  • If you forget to take a dose at your usual time, take it as soon as you remember. If when you remember, it is nearly time for your next dose then take your next dose when it is due but leave out the missed dose. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Try to keep your regular appointments with your doctor. This is so your progress can be monitored. Your doctor will want you to have some blood tests from time to time to check that your kidneys are working well.

  • It is very important that you follow any dietary and lifestyle advice that you are given by your doctor. This may include advice about eating a healthy diet, not smoking, and taking regular exercise.

  • If you buy any medicines, check with a pharmacist that they are suitable to take with captopril. This is because some medicines (such as anti-inflammatory painkillers and indigestion remedies) may interfere with your treatment.

  • It is likely that your doctor will advise that you do not use salt substitutes while you are taking captopril. These products have a high content of potassium which could be harmful for you.

  • If you drink alcohol, ask your doctor for advice about drinking alcohol while you are on captopril. Alcoholic drinks may make you feel light-headed or dizzy, and may not be advisable for you.

  • If you have diabetes you may need to check your blood sugar (glucose) more frequently, as captopril may lower the levels of sugar in your blood. Your doctor will advise you about this.

  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking captopril. This is because some anaesthetics may cause your blood pressure to drop.

  • Treatment with captopril is often long-term unless you experience an adverse effect. Continue to take it unless you are advised otherwise.

  • Very rarely, captopril can cause some people's skin to become more sensitive to sunlight than normal. Use a sunscreen in strong sunlight or until you know how your skin reacts. Do not use sunbeds.

If you are also taking hydrochlorothiazide in combination with this medicine

  • Studies have suggested that taking higher doses of hydrochlorothiazide for long periods of time may increase the risk of certain skin cancers.

  • Tell your doctor if you have ever been treated for skin cancer before.

  • Tell your doctor about any new or changed moles or worrying marks on your skin.

  • Use a sunscreen in strong sunlight. Do not use sunbeds.

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Can captopril cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with captopril. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common captopril side-effects (these affect fewer than 1 in 10 people)

What can I do if I experience this?

Feeling light-headed or dizzy

Getting up more slowly should help. If you begin to feel dizzy, sit or lie down for a few moments before standing. If this continues beyond the first few days, speak with your doctor. Do not drive and do not use tools or machines while you feel dizzy

Dry irritating cough

If this continues, speak with your doctor, as an alternative medicine may be better for you

Feeling sick (nausea) or being sick (vomiting), indigestion, tummy (abdominal) pain, diarrhoea

Stick to bland foods - avoid rich and spicy meals. Drink plenty of water to replace lost fluids


Try to eat a well-balanced diet and drink plenty of water each day

Itchy rash, hair thinning, sleeping problems, unusual taste, dry mouth

Speak with your doctor if any of these become troublesome

Important: if you experience any of the following rare but serious symptoms, stop taking captopril and contact your doctor for advice straightaway:

  • Any difficulty breathing, or swelling of your face, mouth, tongue or throat. These are signs of an allergic reaction.

  • Any yellowing of your skin or the whites of your eyes. These may be signs of jaundice which is a rare side-effect.

  • A severe skin rash.

If you experience any other symptoms which you think may be due to captopril, speak with your doctor or pharmacist for further advice.

How to store captopril

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

  • If using oral liquid medicine, check how long it will keep once opened - after this time, make sure you have a fresh supply.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

MHRA - Reporting adverse reactions

Report suspected side effects to medicines, vaccines, e-cigarettes, medical device incidents, defective or falsified (fake) products to the Medicines and Healthcare products Regulatory Agency to ensure safe and effective use.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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