Key Points
- ACE inhibitors are one of the most important and widely used classes of heart medicines, prescribed for high blood pressure, heart failure, coronary artery disease, and kidney protection in diabetes.
- They work by blocking a hormone system that causes blood vessels to constrict and the body to retain fluid, relaxing the vessels, lowering blood pressure, and reducing the heart’s workload.
- A persistent dry cough is the most common side effect, affecting around 10–15% of patients. If this occurs, your doctor may switch you to an ARB (angiotensin receptor blocker), which provides similar benefits without the cough.
- Emerging evidence suggests ACE inhibitors and ARBs may help slow the development of new plaque growth inside coronary stents (neoatherosclerosis), worth discussing with your cardiologist if you have had stents placed.
- ACE inhibitors must not be taken during pregnancy they can cause serious harm to a developing baby. Always inform your doctor immediately if you become pregnant while taking one.
- Regular kidney function and potassium blood tests are an important and expected part of taking these medicines long-term.
If you have been prescribed an ACE inhibitor, you are in very good company. These medicines have been a cornerstone of cardiovascular care for over four decades, and for good reason, they do far more than simply lower blood pressure.
Whether you have been prescribed one for hypertension, heart failure, a recent heart attack, or to protect your kidneys, understanding how it works and what to expect can help you feel more confident about taking it, and more informed in your conversations with your doctor.
What Is an ACE Inhibitor?
ACE stands for angiotensin-converting enzyme. This enzyme plays a central role in a hormonal pathway called the renin-angiotensin-aldosterone system (RAAS), a system the body uses to regulate blood pressure and fluid balance.
When the RAAS is overactive, as happens in high blood pressure, heart failure, and after a heart attack, it causes blood vessels to constrict and the body to retain too much salt and water. This puts extra strain on the heart and raises blood pressure.
ACE inhibitors block this enzyme, disrupting the chain reaction. Blood vessels relax and widen. The body releases excess fluid. Blood pressure falls. The heart has less to push against, and over time, this protection extends well beyond blood pressure control alone.
ACE inhibitors are one of cardiology’s most versatile tools. What began as a blood pressure medicine has proven to protect the heart after a heart attack, slow heart failure progression, preserve kidney function in diabetes, and potentially reduce arterial inflammation, all from a once-daily tablet.
What Are They Used For?
| Condition | How ACE Inhibitors Help |
|---|---|
| High blood pressure (hypertension) | Relax blood vessels and reduce fluid retention, lowering blood pressure and reducing the risk of heart attack and stroke |
| Heart failure | Reduce the workload on the heart, improve pumping efficiency, ease breathlessness and fatigue, and reduce hospitalisations |
| After a heart attack | Help prevent remodelling, the harmful changes to the heart’s shape and function that can occur after a heart attack, and reduce the risk of future events |
| Coronary artery disease | Reduce cardiovascular risk and provide additional protection beyond blood pressure lowering |
| Diabetic kidney disease | Reduce pressure inside the kidney’s filtering units, slowing the progression of kidney damage in people with diabetes |
| After stroke | Help control blood pressure and reduce the risk of further cardiovascular events |
Common ACE Inhibitors, Names and Doses
There are many ACE inhibitors available. The table below lists the most commonly prescribed, their brand names, and typical tablet strengths. Your doctor will determine the right medicine and dose for your individual circumstances, always follow their guidance rather than adjusting doses yourself.
| Generic Name | Common Brand Names | Typical Tablet Strengths |
|---|---|---|
| Ramipril | Altace, Ramace, Tritace | 1.25mg, 2.5mg, 5mg, 10mg |
| Perindopril | Coversyl, Aceon | 2mg, 4mg, 8mg |
| Lisinopril | Prinivil, Zestril | 2.5mg, 5mg, 10mg, 20mg, 40mg |
| Enalapril | Vasotec, Renitec | 2.5mg, 5mg, 10mg, 20mg |
| Quinapril | Accupril | 5mg, 10mg, 20mg, 40mg |
| Fosinopril | Monopril | 10mg, 20mg |
| Trandolapril | Mavik, Gopten | 1mg, 2mg, 4mg |
| Captopril | Capoten | 12.5mg, 25mg, 50mg |
Most ACE inhibitors are taken once daily, though some (like captopril) are taken two or three times daily. They can be taken with or without food. Tablet strengths vary by region, always check your dispensed packet and confirm with your pharmacist.
Side Effects, What to Expect
Common Side Effects
- Dry cough the most well-known side effect, affecting approximately 10–15% of people. It is caused by the build-up of a substance called bradykinin in the airways, producing a dry, tickling, persistent cough that does not go away. It is more common in women and in people of Asian background. The cough is not dangerous, but it can be very frustrating. If it is affecting your quality of life, speak with your doctor, switching to an ARB typically resolves it completely.
- Dizziness or lightheadedness particularly when starting the medication or after a dose increase. Take your time when standing up. This usually settles as your body adjusts.
- Low blood pressure (hypotension) particularly in people who are dehydrated, on diuretics, or starting at a higher dose. Your doctor will start at a low dose and increase gradually.
- Elevated potassium (hyperkalaemia) ACE inhibitors reduce potassium loss through the kidneys. In some patients, particularly those with kidney disease or on other potassium-raising medicines, levels can rise too high. Regular blood tests monitor this.
- Reduced kidney function a small initial dip in kidney function is common and expected when starting an ACE inhibitor. Blood tests will keep a close eye on this. In most cases it stabilises and the long-term kidney-protective effect outweighs the early change.
- Angioedema a rare but serious reaction involving sudden swelling of the lips, tongue, throat, or face. This requires immediate emergency medical attention. Stop the medicine and call emergency services if this occurs.
The Dry Cough, When to Consider an ARB Instead
The ACE inhibitor cough deserves its own mention because it is so commonly misunderstood. Many patients assume it is a coincidence, a winter cold, allergies, or something else entirely, and continue taking the medicine without realising the connection.
The tell-tale signs are: a dry, tickling cough that does not produce mucus, that is present most of the time, that started or worsened after beginning an ACE inhibitor, and that improves within a few weeks of stopping it.
If this sounds familiar, you do not have to simply put up with it. Angiotensin receptor blockers (ARBs) such as irbesartan, candesartan, losartan, and valsartan, work through a closely related pathway and provide very similar cardiovascular and kidney-protective benefits, without triggering the cough. Switching from an ACE inhibitor to an ARB is a routine and straightforward clinical decision. Raise it with your doctor if the cough is affecting you. For a more detailed look at the ACE inhibitor cough and what to do about it, see our dedicated article: Do You Have a Persisting Dry Cough? Must Read.
Important Safety Points
When to Exercise Extra Caution
- Pregnancy ACE inhibitors are contraindicated in pregnancy. They can cause serious harm to a developing baby, including kidney and skull development problems. If you are pregnant, planning to become pregnant, or become pregnant while taking an ACE inhibitor, inform your doctor immediately so a safe alternative can be arranged.
- Dehydration and illness during periods of significant illness, vomiting, diarrhoea, or dehydration, ACE inhibitors can cause kidney function to deteriorate. Discuss “sick day rules” with your doctor so you know when to pause and when to restart.
- NSAIDs (anti-inflammatory painkillers) regular use of medicines like ibuprofen or naproxen can reduce the effectiveness of ACE inhibitors and increase the risk of kidney problems. Paracetamol is generally the safer choice for pain relief.
- Potassium supplements and salt substitutes many salt substitutes contain potassium chloride. Combined with an ACE inhibitor, this can raise potassium levels too high. Check with your pharmacist before using any salt substitute.
- Regular monitoring kidney function (creatinine and eGFR) and potassium should be checked before starting, within 1–2 weeks of any dose change, and at least annually during long-term use.
A Closer Look, ACE Inhibitors, ARBs and Coronary Stents
An Emerging Insight Worth Knowing About
If you have had a coronary stent placed, this section is particularly worth reading, and worth raising with your cardiologist.
After a stent is placed in a coronary artery, the body heals around it over time. In some patients, a process called neoatherosclerosis can occur, where new plaque-like changes develop inside the stent itself, months to years after the procedure. This is different from the original blockage that led to the stent, and it can contribute to stent-related problems over the long term.
Emerging evidence suggests that ACE inhibitors and ARBs, through their anti-inflammatory and vascular protective effects, may help slow or reduce this process. The renin-angiotensin system plays a role in the inflammatory changes that drive neoatherosclerosis, and blocking it may offer a degree of protection beyond blood pressure control alone.
💡 This is an area of active research and the evidence is still evolving. However, it is a meaningful question to raise with your cardiologist, particularly if you have had multiple stents or a complex coronary history. If you are already on an ACE inhibitor or ARB, this may be an additional reason why your doctor has recommended continuing it long-term. If you are not currently on one, it is worth asking whether it might be appropriate for your situation.
Conclusion
ACE inhibitors are among the most important and evidence-backed medicines in cardiovascular care. Their benefits stretch well beyond blood pressure, protecting the heart after a heart attack, supporting the failing heart, preserving kidney function, and potentially slowing arterial changes that can affect stents over time.
Like all medicines, they require awareness, particularly around the dry cough, potassium levels, kidney monitoring, and pregnancy safety. Most side effects are manageable, and where the cough is a problem, switching to an ARB is a simple and effective solution.
If you have any questions about your ACE inhibitor, why it was prescribed, how long to continue it, or whether it is still the right choice for your situation, your cardiologist or GP is always the best person to ask. These are exactly the kinds of conversations that lead to better-informed, more confident care.
