ACE Inhibitors and ARBs: Managing Blood Pressure Medications Around Surgery
ACE inhibitors and angiotensin receptor blockers (ARBs) are among the most commonly prescribed blood pressure medications. Managing them correctly around surgery is critical because holding them at the wrong time or restarting them too soon can cause dangerous low blood pressure or kidney injury. This guide explains the recommendations used by most surgeons and anesthesiologists.
What ACE Inhibitors and ARBs Do
ACE inhibitors block an enzyme that produces angiotensin II, a hormone that constricts blood vessels and raises blood pressure. Common ACE inhibitors include lisinopril, enalapril, ramipril, and benazepril (most end in -pril).
ARBs block the receptor that angiotensin II binds to, producing a similar blood-pressure-lowering effect by a slightly different pathway. Common ARBs include losartan, valsartan, olmesartan, and irbesartan (most end in -sartan).
Both drug classes are prescribed for high blood pressure, heart failure, diabetic kidney disease, and protection after a heart attack. The decision to hold or continue them around surgery depends partly on why you are taking them.
During surgery, these medications can prevent the normal compensatory blood pressure responses that the body uses to maintain circulation under anesthesia, increasing the risk of severe low blood pressure at induction.
They also impair the kidneys' ability to compensate when blood flow is reduced after surgery, raising the short-term risk of acute kidney injury in patients who are volume depleted (mildly dehydrated from fasting or blood loss).
The Standard Guidance on Holding and Restarting
Most anesthesiology guidelines now recommend holding ACE inhibitors and ARBs on the morning of surgery if you take them primarily for high blood pressure. This single held dose is usually sufficient to reduce intraoperative hypotension risk.
If you take an ACE inhibitor or ARB for heart failure, your cardiologist or surgeon may instruct you to continue it, because the risks of uncontrolled heart failure often outweigh the anesthetic risk of hypotension.
After surgery, restart only when you are eating and drinking normally and your blood pressure and fluid status are stable, typically 24 to 48 hours after a major operation.
If the medication was held for more than 48 hours, some clinicians recommend restarting at half the usual dose for the first few days to reduce the risk of abrupt blood pressure drops.
Always follow the specific instructions your surgeon or anesthesiologist provides. If you did not receive instructions, call the office before fasting begins, not on the morning of surgery.
Kidney Protection During Recovery
Restarting ACE inhibitors or ARBs too soon after surgery, when you are still dehydrated or have low blood pressure, significantly increases the risk of acute kidney injury.
Signs of kidney stress: decreased urination, swelling in the legs, fatigue, or confusion. These warrant prompt contact with your provider.
Stay well hydrated after surgery, unless your surgeon has placed a fluid restriction on you. Good hydration protects the kidneys when you restart these medications.
Your provider may order a basic metabolic panel (blood test) to check kidney function and potassium levels within a week or two of restarting, particularly if you had a major surgery or were ill.
Do not take NSAIDs (ibuprofen, naproxen, ketorolac) regularly while on ACE inhibitors or ARBs without provider approval. This combination increases kidney injury risk substantially.
If you experience light-headedness, dizziness when standing, or very low blood pressure readings after restarting, contact your provider before taking the next dose.
Common Side Effects and Monitoring
ACE inhibitors cause a persistent dry cough in 10 to 20% of patients due to bradykinin accumulation. If this is bothersome, ask your provider about switching to an ARB, which does not share this side effect.
Both drug classes can raise potassium levels (hyperkalemia). Avoid potassium supplements, salt substitutes containing potassium, and large amounts of high-potassium foods without provider guidance while on these medications.
Dizziness or light-headedness on standing (orthostatic hypotension) is common when starting or increasing doses. Rise slowly from seated or lying positions.
These medications are absolutely contraindicated during pregnancy. Women who become pregnant while taking either drug class must contact their provider immediately for an alternative.
Frequently asked
Questions patients ask.
Should I take my lisinopril or losartan on the morning of surgery?
For most patients taking these medications for high blood pressure, the guidance is to skip the morning dose on the day of surgery. However, you must confirm this with your surgical team, because the recommendation differs if you take these drugs for heart failure or diabetic kidney disease. Do not guess: call the surgeon's office the day before and ask explicitly.
What happens if I accidentally take my ACE inhibitor before surgery?
Tell your anesthesiologist before the procedure begins. They can prepare additional vasopressor medications (drugs that raise blood pressure) to counteract low blood pressure during induction. Do not try to vomit or take any action on your own. In most cases, surgery can proceed safely with proper anesthesia management.
Why did my blood pressure run low after surgery even though I held my dose?
Post-surgical low blood pressure has many causes beyond these medications, including anesthesia effects, fluid shifts, blood loss, pain, and fasting. If your blood pressure is consistently low during recovery, your care team will evaluate all contributing factors, which may include temporarily delaying the restart of your blood pressure medications.
Can I take ibuprofen while on lisinopril for pain after surgery?
Combining ACE inhibitors or ARBs with NSAIDs like ibuprofen or naproxen increases the risk of acute kidney injury, particularly in the first weeks after surgery when kidneys are already under stress. Use acetaminophen as your first-line over-the-counter pain reliever unless your provider specifically approves an NSAID.
For patients
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This guide provides general information. For instructions tailored to your specific procedure, ask your provider about QR Rx care plans.
These medication guides are for educational purposes only and do not replace medical advice. Always follow your healthcare provider's specific medication instructions.
