Captopril - an ACE inhibitor

  • Captopril is used to treat a number of different conditions and is generally well tolerated.
  • The first dose may make you feel dizzy.
  • Some painkillers and indigestion remedies interfere with captoril, so ask your pharmacist for advice before buying any medicines.
Type of medicine ACE inhibitor (angiotensin-converting enzyme inhibitor)
Used for Hypertension
Heart failure
To help prevent problems after a heart attack
Problems associated with diabetes
Also called Capoten®, Ecopace®
Also available as: Capozide® (captopril with hydrochlorothiazide), and co-zidocapt (captopril with hydrochlorothiazide)
Available as Tablets

Captopril is used mainly in the treatment of hypertension (high blood pressure) and heart failure (a condition where the pumping action of the heart is reduced). It is also used in some forms of kidney disease (such as diabetic kidney disease), and after a heart attack, to help protect the heart.

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 relaxes your blood vessels and helps to reduce the amount of water put back into your blood by the kidneys. These actions help to decrease blood pressure. People with high blood pressure often do not feel unwell but, if left untreated, high blood pressure can harm the heart and damage blood vessels, leading to a heart attack or stroke.

In heart failure, there may be too much circulating fluid in your blood vessels. ACE inhibitors help to reduce this. They appear to have a protective effect on the heart and slow the progression of the heart failure.

Captopril can be used on its own or alongside other medicines which reduce blood pressure.

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 or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have kidney problems.
  • If you use salt substitutes which contain potassium.
  • If you are dehydrated - for example, if you have had diarrhoea or sickness very recently.
  • If you have been told you have atherosclerosis (a build-up of fatty deposits on the walls of your arteries).
  • If you have peripheral vascular disease (a particular type of poor circulation).
  • If you have collagen vascular disease, such as systemic lupus erythematosus (SLE) or scleroderma.
  • If you have been told you have cardiomyopathy (cardiac muscle disease), or aortic stenosis (narrowing of the main blood vessel from your heart).
  • If you have ever had angio-oedema (where your face, tongue or throat swell).
  • If you are having desensitisation treatment to protect against bee and wasp stings.
  • If you have dialysis treatment, or treatment to remove cholesterol from your blood by a machine (LDL apheresis).
  • If you are taking other medicines, including those available to buy without a prescription, herbal or complementary medicines.
  • If you have ever had an allergic or unusual reaction to any other ACE inhibitor (such as ramipril, lisinopril and perindopril), or to any other medicine.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about the specific brand of captopril you have been given, and a full list of possible side-effects from taking it.
  • Take captopril exactly as your doctor has told you to. Your doctor or pharmacist will tell you how much to take and when to take it. Your dose will also be on the label of the pack. (You may be asked to take captopril once, twice or three times a day depending on the reason why you are taking it).
  • Your doctor may advise you take your very first dose of captopril at bedtime. This is because you may feel dizzy when you first start taking captopril.
  • After this first dose, take captopril at a time of day you find easy to remember. 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.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • 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 to check on your kidney function from time to time.
  • It is very important that you follow any dietary and lifestyle advice that you may have been given by your doctor, such as eating a healthy diet, not smoking, and taking regular exercise.
  • Captopril may cause your skin to become more sensitive to sunlight. Use a sunscreen that protects against UVA light and has a sun protection factor (SPF) of at least 15, especially in strong sunlight or until you know how your skin reacts. Do not use sunbeds.
  • 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 these tablets.
  • If you drink alcohol, ask your doctor for advice about taking captopril and alcohol. Alcohol will increase feelings of light-headedness and may not be recommended for you.
  • If you have diabetes you may need to check your blood glucose more frequently as these tablets 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 captopril taken with an anaesthetic may make your blood pressure drop too low.
  • Treatment with captopril is usually long-term unless you experience an adverse effect. Continue to take the tablets unless you are advised otherwise.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common captopril side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this?
Feeling light-headed or dizzy, especially when standing up Getting up more slowly should help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments before standing. If this continues beyond the first few days, speak with your doctor
Dry irritating cough If this continues, speak with your doctor, as an alternative medicine may be better for you
Feeling or being sick, indigestion, abdominal pain, diarrhoea Stick to bland foods - avoid rich and spicy meals
Constipation Try to eat a well-balanced diet and drink plenty of water each day
Itchy rash, hair thinning, difficulty sleeping, 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 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 this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never take more than the prescribed dose. If you suspect that someone has taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. 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.
  • Never 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.

Further reading & references

  • British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, Capoten® Tablets; Manufacturer's PIL, Capoten® Tablets, E. R. Squibb & Sons Limited, electronic Medicines Compendium. Dated May 2010.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
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Peer Reviewer:
Prof Cathy Jackson
Document ID:
3454 (v27)
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