Medications
ACE Inhibitors & ARBs Before Surgery
ACE inhibitors and ARBs are common blood-pressure and heart medicines, and surgery is one of the few times they're often paused — but not always, so you need a clear instruction for your dose.
Quick answer
Why it matters
Anaesthesia lowers your blood pressure on its own. ACE inhibitors and ARBs relax and widen your blood vessels, so taking one on the morning of surgery can stack on top of that effect and cause pressure to fall further — sometimes low enough to be hard to correct during the operation. Because of this, many teams ask you to skip the single morning dose so your pressure is steadier while you're asleep.
It isn't a blanket stop, though. The decision depends on why you take the medicine, your kind of surgery, and your usual blood pressure, which is why advice ranges from "hold the morning dose" to "take it as normal." When an ACE inhibitor or ARB is treating heart failure rather than blood pressure alone, the balance often tips toward continuing it — stopping can let heart-failure symptoms build up.
Importantly, holding means missing just the dose around surgery, not stopping the medicine for days. You normally restart soon afterwards, once you're stable and drinking again. If you're unsure which of your tablets is an ACE inhibitor or ARB, the medication checker can help you spot the "-pril" and "-sartan" names to ask about.
Do not stop without instruction
What to ask your doctor
- Should I take or hold my ACE inhibitor / ARB on the morning of surgery?
- I take it for heart failure — does that change whether I continue it?
- When do I restart it after the operation?
- Which of my other blood pressure medicines do I take that morning, and which do I hold?
Red flags — call your team
Red flags — call your team
- Very high blood pressure on the day of surgery (for example above 180/110), or symptoms like a severe headache
- New or worsening breathlessness, swollen ankles, or trouble lying flat if you take it for heart failure
- Feeling faint, dizzy, or very weak from blood pressure that seems too low
References
- Perioperative medication guidance from the American College of Cardiology / American Heart Association (ACC/AHA) and the American Society of Anesthesiologists (ASA) notes that ACE inhibitors and ARBs are frequently withheld on the day of surgery to reduce intraoperative hypotension, with continuation considered in selected patients such as those with heart failure. acc.org · asahq.org
- These are general guidelines — your own surgical and anaesthetic team's instruction always takes precedence, because they decide based on your medicines, your heart, and your specific operation.
Frequently asked questions
How do I know if my tablet is an ACE inhibitor or an ARB?
ACE inhibitors usually end in "-pril" — ramipril, lisinopril, enalapril, perindopril. ARBs usually end in "-sartan" — losartan, candesartan, valsartan, irbesartan. Both are used for blood pressure and some heart conditions. If you're not sure, bring your boxes to your pre-op visit, or use our medication checker, and ask whether to take or hold the dose around surgery.
Why are ACE inhibitors and ARBs often held before surgery?
They widen your blood vessels to lower blood pressure. Anaesthesia also lowers pressure, so taking one on the morning of surgery can cause an exaggerated drop that's harder to correct while you're asleep. Holding the single morning dose helps keep your pressure steadier during the operation. It's a precaution around the procedure, not a reason to stop the medicine long term.
I take ramipril for heart failure — should I stop it?
Not on your own. When an ACE inhibitor or ARB is treating heart failure, the decision is more nuanced and it's often continued, because stopping can let heart-failure symptoms build. Some teams still hold the day-of dose. Ask your surgical and anaesthetic team specifically what to do with it, and don't pause it without their advice.
When do I restart my ACE inhibitor or ARB after surgery?
Usually fairly soon — often within a day or so, once your blood pressure is stable, you're drinking normally, and your kidney function and fluids are settled. The exact timing depends on your operation and how you recover, so follow the plan your team gives you rather than restarting automatically. If no one has told you, ask before you leave.