ACE inhibitors protect the heart and kidneys in millions of people. Their best-known side effect is a nagging dry cough, but there are other important things to know.
Imagine starting ramipril for blood pressure. A month later you have a tickly, dry cough that will not go away. You try cough syrups and wonder if you have an infection. The cough is actually from the tablet.
How ACE inhibitors work
Angiotensin-converting enzyme (ACE) inhibitors block an enzyme that produces angiotensin II, a hormone that narrows blood vessels and makes the body hold on to salt and water. Blocking it relaxes blood vessels, lowers blood pressure and reduces strain on the heart and kidneys.,Common ACE inhibitors include ramipril, lisinopril, enalapril and perindopril. Their names usually end in “-pril”.
What they are used for
- High blood pressure
- Heart failure with reduced ejection fraction
- After a heart attack
- Protecting the kidneys in diabetes and chronic kidney disease, especially when there is protein in the urine
- Reducing the risk of heart attack and stroke in some high-risk people
The dry cough
Around 1 in 10 people taking an ACE inhibitor develop a persistent dry, tickly cough. It is caused by a build-up of a substance called bradykinin in the airways. It can start days or months after starting the medicine and does not respond to cough medicines.,If the cough is troublesome, your healthcare provider can switch you to an angiotensin receptor blocker (ARB), such as losartan or candesartan, which works in a similar way but rarely causes a cough. The cough usually settles within a few weeks of stopping the ACE inhibitor.
Other common side effects
- Dizziness or light-headedness, especially after the first dose or when standing
- Headache
- Tiredness
- Raised potassium levels
- Changes in kidney function on blood tests
Angioedema: a rare but serious side effect
Rarely, ACE inhibitors cause angioedema: swelling of the face, lips, tongue or throat. It can happen at any time, even after years of taking the medicine, and is more common in people of African or Caribbean descent.,If you develop swelling of the lips, tongue or throat, or difficulty breathing or swallowing, call emergency services immediately and stop taking the medicine. Anyone who has had angioedema with an ACE inhibitor should not take one again.
Blood tests
Your healthcare provider will usually check your kidney function and potassium before you start, one to two weeks after starting or increasing the dose, and then regularly, often yearly. A small rise in creatinine is expected and usually acceptable, but larger rises or high potassium may mean the dose needs changing.
Pregnancy
ACE inhibitors can harm an unborn baby, particularly in the second and third trimesters. If you could become pregnant, use reliable contraception and talk to your healthcare provider before trying to conceive. If you find out you are pregnant, contact your healthcare provider promptly; do not simply stop the medicine without advice, as your blood pressure may need a different treatment.
Sick day rules
If you become unwell with vomiting, diarrhoea or fever and cannot drink normally, your healthcare provider may advise you to pause your ACE inhibitor temporarily, to protect your kidneys from injury. Restart when you are eating and drinking normally, usually after 24 to 48 hours. Only follow this if your healthcare team has advised it for you.
Interactions
- Potassium supplements, salt substitutes containing potassium and potassium-sparing diuretics such as spironolactone can raise potassium too high
- Anti-inflammatory painkillers such as ibuprofen can reduce the blood pressure effect and strain the kidneys
- Lithium levels can rise
- ARBs and aliskiren are not usually combined with ACE inhibitors
Frequently asked questions
When should I take it?
Many people take the first dose at bedtime to reduce dizziness. After that, follow your prescriber’s advice.
Can I take ibuprofen?
Occasional use may be OK for some people, but regular use can harm the kidneys. Check with your pharmacist.
Will I need it for life?
Often yes for long-term conditions like heart failure or high blood pressure, but your treatment will be reviewed regularly.
But my blood pressure is now normal. Can I stop?
Your blood pressure is likely normal because of the medicine. Stopping usually makes it rise again. Talk to your healthcare provider before making changes.
Your next step: If you have had a dry cough since starting an ACE inhibitor, mention it at your next appointment and ask whether an ARB would suit you.
Related: Home blood pressure monitoring · Kidney function tests
Sources: British National Formulary (BNF), National Institute for Health and Care Excellence (NG136), American Heart Association, US Food and Drug Administration.
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