- A persistent dry cough, often worse at night, is the most common side effect of ACE inhibitor blood pressure medicines, the ones whose names end in “-pril”.
- It affects roughly one in ten people taking them, and is more common in women. It can begin within weeks of starting, or after months or even years of taking the same tablet without difficulty.
- The cause is a build-up of a substance called bradykinin, which irritates the airways. It has nothing to do with infection, asthma, or reflux, which is why cough medicines and antihistamines make no difference.
- Switching to a closely related medicine called an ARB usually resolves it within a few weeks, and provides comparable cardiovascular protection.
- The medicines themselves are among the most effective in cardiovascular care, so the aim is finding an equivalent alternative rather than going without.
The pattern is familiar enough that I recognise it before the patient finishes describing it. A cough that has been going on for months. Dry, tickling, unproductive. Worse at night, bad enough to disturb sleep and to make sitting through a meeting uncomfortable.
By the time they reach a cardiologist, most have already had a chest X-ray, been tested for asthma, tried reflux treatment, and in recent years been swabbed for covid more than once. Everything has come back normal and the cough has carried on.
Then one question tends to settle it: are you taking a blood pressure tablet whose name ends in “-pril”? Ramipril, perindopril, lisinopril, enalapril. The answer is usually yes.
Why These Tablets Cause a Cough
ACE inhibitors work by blocking an enzyme in the hormonal system that controls blood pressure and fluid balance. Blocking it relaxes blood vessels, reduces fluid retention, and lowers pressure. That is the intended effect and it works well.
The same enzyme, though, has a second job. It breaks down a substance called bradykinin, which is involved in inflammation and in widening blood vessels. When the enzyme is blocked, bradykinin is no longer cleared as efficiently and its levels rise.
Bradykinin accumulating in the airways irritates the lining of the throat and bronchial tubes, and the result is a persistent dry tickle that keeps triggering a cough reflex.
This explains something that frustrates a lot of people. The cough does not respond to cough suppressants, antihistamines, inhalers, or reflux medicines, because none of them touch the actual cause. It is not an infection and not a lung problem. It is the medicine doing exactly what it was designed to do, with an unwanted side consequence.
It tends to be worse lying down, which is why it so often interferes with sleep.
Roughly one in ten people taking an ACE inhibitor develop a persistent dry cough, with reported rates around twice as high in women. It is the most common reason this class of medicine is stopped.
Dicpinigaitis, Chest, 2006
One Thing That Makes This Harder to Spot
Most side effects announce themselves early. This one often does not.
The cough can start within a week of the first tablet, but it can equally appear after six months, or after several years on the same dose without any trouble at all. That delay is the single biggest reason it gets missed, by patients and doctors alike. When a cough starts three years into taking a medicine, nobody thinks of the medicine.
So the useful question is not whether the tablet is new. It is simply whether you are taking one.
How to Tell If You Are on One
The naming convention makes this straightforward. Every ACE inhibitor ends in “-pril”.
| Medicine | Commonly used for |
|---|---|
| Ramipril | Blood pressure, heart failure, after a heart attack |
| Perindopril | Blood pressure, coronary artery disease |
| Lisinopril | Blood pressure, heart failure |
| Enalapril | Blood pressure, heart failure |
| Quinapril | Blood pressure, heart failure |
| Captopril | Blood pressure, heart failure |
| Trandolapril | Blood pressure, after a heart attack |
| Fosinopril | Blood pressure, heart failure |
Brand names vary from country to country, so the generic name printed on the box or the pharmacy label is the more reliable guide. Some combination tablets contain an ACE inhibitor alongside a diuretic or a calcium channel blocker, in which case the “-pril” will still appear somewhere in the name.
What Usually Happens Next
There is a closely related class of medicine called angiotensin receptor blockers, or ARBs, whose names end in “-sartan”. Candesartan, losartan, valsartan, irbesartan, telmisartan.
They act on the same hormonal system but at a different point in it, and they do not affect bradykinin at all. That is why they do not produce the cough. Across most of the conditions these medicines are used for, the cardiovascular benefit is comparable, and switching between the two is a routine change rather than a compromise.
Where the cough is the reason for switching, it usually settles within two to four weeks as bradykinin levels return to normal, though it can occasionally take up to three months to clear entirely.
The switch is made with the prescribing doctor rather than independently, mainly because blood pressure and kidney function are normally rechecked a couple of weeks afterwards. Stopping an ACE inhibitor without a replacement can allow blood pressure to rebound, and in heart failure it removes treatment that is doing significant work.
When It Is Not the Tablet
Switching resolves the cough in most people, but not everyone, and it is worth knowing what else can be responsible.
Post-nasal drip from allergic rhinitis is a common cause. So is reflux, which can produce a chronic cough with very little heartburn to point at it. Cough-variant asthma presents as cough alone with no wheeze. Certain eye drops containing beta-blockers are absorbed into the bloodstream and can contribute.
A cough that persists more than three months after stopping an ACE inhibitor is generally reassessed rather than assumed. Any cough producing sputum, associated with breathlessness, or bringing up blood is investigated on its own terms regardless of what medicines are involved.
A Related and More Serious Effect Worth Knowing About
The same bradykinin mechanism occasionally produces something else, and it is worth recognising because it behaves quite differently from the cough.
Angioedema is a sudden swelling, usually of the lips, tongue, face or throat. It is uncommon, affecting well under one percent of people taking these medicines, but it can develop rapidly and can obstruct breathing. Like the cough, it can appear after years of uneventful treatment.
Swelling of the lips, tongue or throat, or any difficulty breathing or swallowing, is treated as an emergency and assessed immediately rather than at the next available appointment. It is one of the few situations where these medicines are stopped straight away.
Why It Is Worth Mentioning
People are often reluctant to raise medication side effects. There is a sense of not wanting to be difficult, or of seeming ungrateful for treatment that is clearly important, or a worry that complaining might mean losing a medicine that is protecting them.
None of that applies here. This is among the most recognised side effects in cardiovascular medicine, the alternative is well established, and the switch is uncomplicated. Months of disturbed sleep and unnecessary investigations is a high price for a conversation that takes two minutes.
Conclusion
A dry cough that has outlasted every investigation, and that gets worse at night, has a common explanation sitting on the prescription. It is not a lung problem and not something to be endured as the cost of treating blood pressure.
ACE inhibitors are genuinely excellent medicines and have prevented a great many heart attacks and strokes. The point is not to abandon them but to recognise when a straightforward alternative would do the same job without keeping someone awake. Anyone taking a “-pril” tablet who has been coughing for months has good reason to raise it at their next appointment.
Related Reading
- Angiotensin Receptor Blockers (ARBs): How They Work
- The Importance of Monitoring Your Blood Pressure
- When Blood Pressure Won’t Come Down: What Happens Next
- Calcium Channel Blockers: Amlodipine, Felodipine, Nifedipine and More
- Beta-Blockers: How They Work and What to Expect
- Demystifying Heart Failure: HFrEF, HFpEF and HFimpEF
- How to Lower Blood Pressure Naturally
