ACE inhibitors
Fosinopril
An ACE inhibitor that relaxes blood vessels to lower blood pressure and support the heart.
What is Fosinopril?
Fosinopril is an ACE inhibitor used to lower high blood pressure and to treat heart failure. It works by relaxing and widening blood vessels, which eases the workload on the heart. Common issues include a dry cough and a drop in blood pressure with the first doses; it must not be used in pregnancy and needs kidney and potassium monitoring.
Education and reference only. This is a plain-language guide to Fosinopril — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Fosinopril is an angiotensin-converting enzyme (ACE) inhibitor, in the same family as ramipril and lisinopril. In the UK it is used to treat high blood pressure (hypertension) and heart failure. ACE inhibitors are widely used because they both lower blood pressure and help protect the heart and kidneys over time.
How it works
Fosinopril blocks the enzyme that makes angiotensin II, a hormone that tightens blood vessels and makes the body hold on to salt and water. With less angiotensin II, the blood vessels relax and widen and the body sheds some excess fluid, so blood pressure falls and the heart has less to pump against. These effects also reduce strain on the heart in heart failure.
Company & origin
Originated / developed by: Originally developed by Bristol-Myers Squibb; available as a generic medicine..
Developed in the 1980s as an ACE inhibitor and used in the UK for high blood pressure and heart failure.
What it treats
Conditions Fosinopril is used for
Practical use
How to take Fosinopril
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it at the same time each day; the first dose is often taken at bedtime in case it lowers blood pressure.
- Swallow tablets whole with a drink of water.
- Avoid salt substitutes that are high in potassium unless your prescriber agrees.
- Have your blood tests done as arranged to check kidney function and potassium.
- If a dose is missed, take it when you remember unless the next one is near, then skip it; never double up.
- Do not stop suddenly without advice, and tell your prescriber if you become pregnant or plan to.
Weighing it up
Advantages & disadvantages of Fosinopril
Advantages
- Lowers blood pressure and protects the heart in heart failure.
- Can help protect the kidneys, which is valuable for some people with diabetes or kidney disease.
- Taken once daily and available cheaply as a generic medicine.
Disadvantages
- A persistent dry cough is common and leads some people to switch medicines.
- Can cause a sharp drop in blood pressure with the first dose, and raise potassium.
- Must not be used in pregnancy, and rarely can cause serious swelling (angioedema).
Practical use
Good to know
A persistent dry, tickly cough is the best-known side effect of ACE inhibitors. The first dose can lower blood pressure more than later ones, so it is often taken at bedtime to start with. Your kidney function and potassium are checked with blood tests. ACE inhibitors must not be used in pregnancy. Seek urgent help for any swelling of the face, lips or tongue.
Who should not take it / use with caution
- People who are pregnant or planning pregnancy.
- People who have had angioedema (serious swelling) with an ACE inhibitor before.
- People with narrowing of the arteries to both kidneys, or very high potassium, without specialist advice.
Monitoring
- Kidney function and potassium with blood tests before and after starting or increasing the dose.
- Blood pressure, particularly around the first doses.
- Any new cough or swelling of the face, lips or tongue.
Side effects
- A dry, persistent cough.
- Dizziness or low blood pressure, especially with the first doses.
- Raised potassium and changes in kidney function.
- Headache, tiredness and, rarely, swelling of the face, lips or tongue (angioedema).
Key interactions
- Potassium supplements, potassium-sparing diuretics and potassium-based salt substitutes.
- NSAIDs such as ibuprofen, which can reduce its effect and strain the kidneys.
- Other blood-pressure-lowering medicines, lithium and certain diabetes medicines.
- Other medicines acting on the same hormone system (ARBs, or aliskiren) are generally avoided together because of the risk to the kidneys and high potassium.
- Taking an ACE inhibitor together with a water tablet (diuretic) and an anti-inflammatory painkiller (NSAID) can cause sudden kidney injury — the so-called 'triple whammy'.
Available as: Available as tablets.
Answers
Fosinopril: frequently asked questions
Why does fosinopril cause a dry cough?
ACE inhibitors can let certain natural substances build up in the airways, which triggers a persistent dry, tickly cough in some people. If it is troublesome, your prescriber can switch you to a related medicine that is less likely to cause it.
Why is the first dose taken at bedtime?
The first dose can lower blood pressure more than later ones, which may cause dizziness. Taking it at bedtime means you are lying down if this happens.
Can I take it in pregnancy?
No. ACE inhibitors can harm an unborn baby and must not be used in pregnancy. Tell your prescriber straight away if you become pregnant or are planning to.
Should I avoid potassium?
Fosinopril can raise potassium, so avoid potassium-based salt substitutes and potassium supplements unless your prescriber agrees, and have your blood checked as arranged.
What should I do if my face or lips swell?
Swelling of the face, lips, tongue or throat can be a serious reaction called angioedema. Stop the medicine and seek urgent medical help straight away.
The wider class
About ACE inhibitors
Fosinopril belongs to the ace inhibitors class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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