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Fosinopril - an ACE inhibitor

The first dose of fosinopril can make you feel dizzy. It is best taken at bedtime.

Fosinopril is generally well tolerated but if you develop a troublesome cough, you should let your doctor know.

Some painkillers and indigestion remedies interfere with fosinopril. Ask your pharmacist for advice before you buy any medicines 'over the counter'.

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About fosinopril

Type of medicine

An angiotensin-converting enzyme (ACE) inhibitor

Used for

High blood pressure; heart failure

Also called

Fosinopril sodium

Available as


Fosinopril belongs to a class of medicines called angiotensin-converting enzyme (ACE) inhibitors. You may have been prescribed it to reduce high blood pressure (hypertension), or to treat heart failure. Heart failure is a condition where your heart does not work as well as it should.

ACE inhibitors like fosinopril 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. 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.

In heart failure, there can be too much circulating fluid in your blood vessels because your heart is not working as efficiently as it once did. Fosinopril helps to reduce this. It also appears to have a protective effect on the heart and slows the progression of the heart failure.

Before taking fosinopril

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

  • If you are pregnant or breastfeeding.

  • If you have any problems with the way your kidneys work, or any problems with the way your liver works.

  • 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 captopril, ramipril or perindopril), or to any other medicine.

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How to take fosinopril

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

  • Take the tablets exactly as your doctor tells you to. Fosinopril is taken once a day. If you have high blood pressure, your doctor will advise you take your very first dose at bedtime. This is because you can feel quite dizzy when you first start taking it. After the first dose, you can generally take fosinopril at a time of day you find easy to remember. For most people this will be in the morning.

  • Try to take your doses at the same time of day each day as this will help you to remember to take your doses regularly. You can take fosinopril tablets either with or without food. It is best to swallow the tablet with a drink of water.

  • There are two strengths of fosinopril tablets - 10 mg and 20 mg. It is usual to start by taking the 10 mg strength tablets, although your doctor may increase your dose over the first few weeks. This allows your doctor to make sure that you have the dose that helps your condition and helps to avoid any unwanted side-effects, such as dizziness. Each time you collect a new supply, check to make sure the tablets are the strength that you are expecting.

  • If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, leave out the forgotten dose from the previous day and take the dose that is due as normal. Do not take two doses at the same time to make up for a missed 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 have been given by your doctor. This can 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 fosinopril. This is because some medicines (such as anti-inflammatory painkillers and indigestion remedies) can interfere with your treatment.

  • It is likely that your doctor will advise that you do not to use salt substitutes while you are taking fosinopril. 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 fosinopril. Alcoholic drinks can make you feel light-headed or dizzy, and they may not be advisable for you.

  • If you have diabetes you may need to check your blood sugar (glucose) more frequently, as the tablets can 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 fosinopril. This is because some anaesthetics could cause your blood pressure to drop too low.

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

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Can fosinopril 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 more common ones associated with fosinopril. The best place to find a full list of the side-effects which can be associated with your medicine, is from the manufacturer's printed information leaflet supplied with the medicine. Alternatively, you can find an example of a manufacturer's information leaflet in the reference section below. Speak with your doctor or pharmacist if any of the following continue or become troublesome.


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

What can I do if I experience this?

Dry irritating cough

If this continues, speak with your doctor, as a different type of medicine may be more suitable for you

Feeling dizzy or weak

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. Do not drive and do not use tools or machines while you feel dizzy

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

Stick to simple foods - avoid fatty or spicy meals

Headache, muscle aches and pains, chest pain, cold and flu-like symptoms, sore throat

Ask your pharmacist to recommend a suitable remedy

Blurred eyesight

Do not drive and do not use tools or machines while affected

Tingling feelings, feeling tired, fast heartbeat, skin rash, mood changes, sleeping problems, sexual problems, difficulties passing urine

If any of these become troublesome, speak with your doctor

Important: if you experience any of the following potentially serious symptoms, stop taking fosinopril 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 a liver problem called jaundice, which is a rare side-effect.

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

How to store fosinopril

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

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

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.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

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

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