Lisinopril and Olmesartan: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Olmesartan
Lisinopril
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Olmesartan (Benicar) and lisinopril (Prinivil, Zestril) both lower blood pressure by working on the same body system, called the renin-angiotensin-aldosterone system. Olmesartan is an ARB and lisinopril is an ACE inhibitor. Taking both together doubles down on that one system, which can push things too far.
That can lead to blood pressure dropping too low (dizziness or fainting), too much potassium in your blood, and strain on your kidneys. Because of this, doctors usually avoid using both at the same time. If you have been prescribed both, please don't stop either one on your own. Instead, check in with your pharmacist or doctor so they can review and manage this safely.
Mechanism: Dual RAAS blockade. Olmesartan (ARB) and lisinopril (ACE inhibitor) act on the same pathway; neither is a prodrug relevant here, so combined use produces additive pharmacodynamic effect rather than a PK interaction.
Effect (established evidence): Increased incidence of hypotension, syncope, hyperkalemia, and deterioration in renal function (including acute renal failure) versus monotherapy, particularly in atherosclerotic disease, heart failure, or diabetes with end-organ damage.
Management:
- Generally avoid concomitant use.
- If unavoidable, closely monitor blood pressure, serum potassium, and renal function (SCr/eGFR).
- Individualize dosing per care team; consider discontinuing one agent.
What happens
Increased risk of adverse events (ie, hypotension, syncope, hyperkalemia, changes in renal function, acute renal failure)
Interaction Deep Dive
Combining an ACE inhibitor with an angiotensin receptor blocker (ARB), thereby producing dual blockade of the renin-angiotensin-aldosterone system, has been linked to a higher rate of adverse effects. Among patients who have established atherosclerotic disease, heart failure, or diabetes accompanied by end organ damage, giving an ACE inhibitor together with an ARB produced a greater incidence of hypotension, syncope, hyperkalemia, and alterations in renal function (including acute renal failure) than was seen with either drug used by itself 3. As a rule, this combination should be avoided; if coadministration cannot be avoided, monitor blood pressure, renal function, and electrolytes closely 4. A meta-analysis conducted in patients with left ventricular dysfunction found that adding an ACE inhibitor to ARB therapy raised the overall risk of adverse events prompting treatment discontinuation relative to ACE inhibitor therapy used alone 1.
Why it happens (mechanism)
Dual blockade of the renin-angiotensin-aldosterone system
How to manage this interaction
The most common approach is to avoid using these two together, since combining an ARB (olmesartan) and an ACE inhibitor (lisinopril) rarely adds benefit and raises the risk of low blood pressure, high potassium, and kidney problems.
If your care team decides you need both, they can manage it by:
- Checking your blood pressure regularly
- Running blood tests for potassium and kidney function
- Adjusting and individualizing your doses as needed
What you should do: keep taking both exactly as prescribed for now, and ask your pharmacist or doctor to confirm whether both are still meant to be part of your regimen.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A systematic review and meta-analysis involving 18,160 patients with heart failure or left ventricular dysfunction drawn from 9 randomized trials found that adding an angiotensin receptor blocker (ARB) to ACE inhibitor therapy was linked to a greater risk of adverse events resulting in treatment discontinuation, compared with ACE inhibitor therapy used alone. Every patient had NYHA functional class II to IV heart failure, an ejection fraction of 45% or lower, or left ventricular dysfunction occurring acutely after myocardial infarction. The agents studied were losartan, candesartan, valsartan, irbesartan, and telmisartan. Follow-up ranged from 4 weeks to 41 months. The analysis showed that combined therapy raised the risk of experiencing any adverse effect by 2.3%. The risk of hypotension rose by 1.1%, the risk of worsening renal function rose by 1%, and the risk of hyperkalemia rose by 0.6%. However, the risk of angioedema or cough was not significantly different between the treatment arms. When a combination approach is justified, patients should be monitored closely for possible adverse effects 1.
Common questions
Can I take Lisinopril and Olmesartan together?
Combining olmesartan and lisinopril blocks the same blood pressure system twice, raising the risk of low blood pressure, high potassium, and kidney trouble; this combo is usually avoided, so check with your prescriber or pharmacist. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lisinopril and Olmesartan interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Lisinopril and Olmesartan interaction managed?
The most common approach is to avoid using these two together, since combining an ARB (olmesartan) and an ACE inhibitor (lisinopril) rarely adds benefit and raises the risk of low blood pressure, high potassium, and kidney problems. If your care team decides you need both, they can manage it by: Checking your blood pressure regularly Running blood tests for potassium and kidney function Adjusting… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Lisinopril or Olmesartan need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (4)
- Lakhdar R, Al-Mallah MH, & Lanfear DE: Safety and tolerability of angiotensin-converting enzyme inhibitor versus the combination of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker in patients with left ventricular dysfunction. J Card Fail 2008; 14(3):181-188.
- Product Information: Lotensin(R) oral tablets, benazepril HCl oral tablets. Validus Pharmaceuticals LLC (per FDA), Parsippany, NJ, 2014. DailyMed
- Product Information: COZAAR(R) oral tablets, losartan potassium oral tablets. Merck Sharp & Dohme Corp. (per FDA), Whitehouse Station, NJ, 2011. DailyMed
- Product Information: EXFORGE oral tablets, amlodipine valsartan oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2019. DailyMed
Keep reading about Olmesartan
Keep reading about Lisinopril
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