ACE inhibitors, examples and side effects

As an experienced clinician you’re already likely to know what Angiotensin-converting enzyme (ACE) inhibitors are. As a quick reminder, they’re essentially drugs used to treat high blood pressure and congestive heart failure. They are also used to prevent kidney disease in certain patients.

ACE inhibitors work to dilate the blood vessels and lower the blood pressure by inhibiting the actions of angiotensin-converting enzyme (ACE), an enzyme that helps regulate blood pressure.

Examples of ACE inhibitors

ACE inhibitors are divided into two categories based on their length of duration – short-acting or long-acting. Both therapy options are extremely effective, although the advantage of long-acting ACE inhibitors is less frequent dosing. Captopril, for example, is a short-acting ACE inhibitor which has to be taken three times a day. Conversely, Lisinopril is longer lasting with only one dose a day needed for maximum effect.

Which ACE inhibitor a patient should be prescribed must be based on their overall health as well as the condition they’re being treated for.

As well as Captopril and Lisinopril, other examples of ACE inhibitors include:

  • Benazepril
  • Enalapril
  • Fosinopril
  • Moexipril
  • Ramipril
  • Trandolapril

What are the most common side effects of ACE inhibitors?

ACE inhibitors are associated with few side effects and are generally tolerated well. However, reported side effects include:

A dry cough that irritates the throat

This is a particularly common side effect in people taking ACE inhibitors, occurring in around 1 in 10 patients. It comes about because ACE inhibitors cause inflammatory compounds such as bradykinin and substance P to accumulate.

Once the patient stops taking the medication, the cough should disappear within 8 to 12 weeks. Changing the type of ACE inhibitor won’t help, as it’s a relatively common side effect amongst all of them.

Hyperkalemia (elevated potassium levels in the blood)

ACE inhibitors lower the levels of aldosterone, a hormone that regulates the excretion of potassium in the kidneys via urine. Potassium is then likely to be retained in the kidneys and bloodstream.

An increased risk of hyperkalemia is present in individuals with kidney disease or diabetes who are taking ACE inhibitor medication. Symptoms of hyperkalemia include confusion, muscle cramps and general weakness. In severe cases, hyperkalemia can bring on dangerous cardiac arrhythmias.

It’s essential to take great care when prescribing ACE inhibitors to individuals who fall into this category.

Light-headedness and dizziness

Light-headedness and dizziness are much less commonly reported and are more likely to occur in patients with known hypotension. As hypotension can often be related to heart failure, extreme caution should be taken when such patients begin or change their ACE inhibitor medication.

Dysgeusia (an abnormal taste in the mouth)

This is a very common side effect in those who take ACE inhibitors due to sulfhydryl moiety being present. Patients have particularly reported that Captopril, for example, leaves them with a metallic taste. However, after prolonged use dysgeusia tends to disappear.


Angioedema (swelling under the skin) only occurs in around 0.1-0.2% of patients, however it’s the most severe side effect reported.

Accumulation of fluid (and bradykinin) can obstruct the airway, although the severity depends on which areas of the body are affected.

Swelling of the lips, mouth and tongue may occur in milder cases of angioedema. However, any patients experiencing angioedema whilst taking an ACE inhibitor must stop immediately and not take any more ACE inhibitors in future.

Renal impairment

ACE inhibitors inhibit efferent renal arteriolar vasoconstriction which then reduces the filtration rate of the kidney. This can lead to renal impairment. However, such impairment can be reversed once the patient has stopped taking the drug.

Other side effects

Various other fairly minor side effects have also been associated with the use of ACE inhibitors. These include headaches, fatigue, weakness, fainting and sexual dysfunction. Some people also experience vomiting and diarrhoea which in turn can bring about hypotension. Patients suffering with vomiting and diarrhoea must therefore be strongly encouraged to stay well hydrated and treat any sudden deterioration in their condition as an emergency.

Are you a clinician who sees patients with hypertension and cardiac failure?

If so, PDUK’s Medicines optimisation in Hypertension and Heart Failure course is well worth considering. Now being offered via Zoom, it’s a great opportunity to gain a valuable 4 CPD hours over half a day from home.

This flexible and highly interactive programme allows nurses, health visitors and other allied health practitioners to increase their knowledge in this hugely diverse subject area. It looks in detail at important issues non-medical prescribers face regularly, including polypharmacy and patient monitoring. Structured medication reviews are also discussed along with current guidelines.

We’re seeing plenty of interest though so make sure you book up early to avoid disappointment!

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