8 Olmesartan Interactions to Watch For

Olmesartan (Benicar) has been used for over two decades to treat high blood pressure. It’s part of a group of medications called angiotensin II receptor blockers (ARBs). Like most medications, it has possible drug interactions to consider before taking it. 

Below, we discuss eight of the most important olmesartan interactions to watch for.

1. Potassium-sparing diuretics like spironolactone (Aldactone)

Spironolactone (Aldactone) is a type of diuretic (water pill). It’s prescribed for many health conditions, including heart failure and high blood pressure. Diuretics work by helping your body get rid of fluid. And most diuretics cause you to lose certain electrolytes, including potassium and sodium.

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But spironolactone is unique because it prevents potassium loss in the urine. It’s called a potassium-sparing diuretic. Other examples of potassium-sparing diuretics include amiloride (Midamor) and eplerenone (Inspra).

Like all ARBs, olmesartan can increase blood levels of potassium. So if you take olmesartan with potassium-sparing diuretics, you increase your risk of hyperkalemia (high blood potassium). Hyperkalemia often doesn’t cause symptoms. But if it does, you may notice tiredness, muscle weakness, and tingling. More serious symptoms include heart palpitations, shortness of breath, and chest pain.

Some people may need to take olmesartan with spironolactone or another potassium-sparing diuretic. Your prescriber may monitor your potassium levels more closely in this case. So make sure to complete any lab tests they order for you. And if you have symptoms of hyperkalemia during treatment, let your prescriber know.

2. Potassium supplements

Potassium supplements increase the amount of potassium in your blood. They may be helpful if you have low potassium levels (hypokalemia). They’re available as prescription and over-the-counter (OTC) products. Examples include potassium chloride (Klor-Con), potassium citrate (Urocit-K), and potassium gluconate. Some multivitamins also contain potassium, though usually in small amounts.

Olmesartan can also increase potassium levels. So taking it with potassium supplements increases your risk of hyperkalemia. Before taking olmesartan, talk to your prescriber if you’re taking a potassium supplement. They can help you weigh the risks. In many cases, they may recommend avoiding potassium supplements with olmesartan. 

3. ACE inhibitors like lisinopril (Zestril)

Angiotensin-converting enzyme (ACE) inhibitors are another group of blood pressure medications. Examples include lisinopril (Zestril), benazepril (Lotensin), and enalapril (Vasotec).

Both ACE inhibitors and ARBs are first-choice medications for high blood pressure. They work similarly, so combining them isn’t typically recommended. Many studies show an increased risk of side effects if they’re combined. This includes blood pressure that’s too low (hypotension), hyperkalemia, and kidney problems.

ACE inhibitors and ARBs are prescribed for other conditions besides high blood pressure. This includes heart failure, chronic kidney disease, and after a heart attack. But your prescriber will help you choose an ACE inhibitor or ARB in these situations. Switching between the two is also possible, but you’ll want to follow your prescriber’s instructions for how to do this.

4. Aliskiren

Aliskiren (Tekturna) is a medication that treats high blood pressure. It’s not considered a first-choice medication for this condition, though.

Aliskiren works similarly to ARBs and ACE inhibitors. So taking aliskiren with olmesartan isn’t usually recommended, especially if you have diabetes or kidney disease. If you have these health conditions, you should completely avoid taking aliskiren with olmesartan.

5. Entresto

Entresto treats heart failure in certain adults and children. It’s a combination of the medications sacubitril and valsartan. Like olmesartan, valsartan (Diovan) is an ARB. Taking more than one ARB isn’t recommended because it increases your risk of side effects. This includes blood pressure that’s too low, hyperkalemia, and kidney problems.

If you’re not sure whether you’re taking a medication that contains an ARB, ask your pharmacist to check for you. Give them a list of the medications you take. They’ll be able to tell you whether any of your medications may interact with olmesartan.

6. NSAIDs like ibuprofen (Advil, Motrin)

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to relieve pain, fever, and inflammation. Examples include ibuprofen (Advil, Motrin), celecoxib (Celebrex), and naproxen (Aleve, Naprosyn).

Using olmesartan and NSAIDs at the same time increases your risk for kidney problems. In severe cases, it can lead to acute kidney injury (AKI). It’s even more likely if you’re also using a diuretic. Symptoms of AKI include:

• Swelling in your ankles or feet

• Peeing less than usual or not at all

• Tiredness

• Weakness

• Confusion

If your prescriber thinks it’s safe for you to take olmesartan and an NSAID, they’ll likely monitor your kidney function more closely. If you develop symptoms of a kidney problem, contact your prescriber. If your symptoms feel severe, seek emergency care.

Good to know: Research shows that NSAIDs can also increase blood pressure. The change is usually small. But this can counteract the blood pressure-lowering effect of olmesartan. If you take an NSAID, let your prescriber know — even if you don’t use it regularly. They may ask you to monitor your blood pressure more closely at home.

7. Lithium

Lithium (Lithobid) is a medication that treats bipolar disorder. Olmesartan may increase the amount of lithium in your system. This can cause side effects like peeing frequently, tremors, and feeling thirsty. More seriously, this puts you at risk of lithium toxicity.

Symptoms of moderate to severe toxicity include confusion, agitation, and a rapid heartbeat. You may also have slurred speech, worsening tremors, and extreme nausea. Uncontrolled muscle movements, seizures, and trouble breathing are severe symptoms. These warrant emergency care.

Lithium is a narrow therapeutic index medication. This means there’s a small difference between blood levels of lithium that are safe and those that cause toxicity. If you take lithium, you’ll likely have regular blood tests to check your lithium levels. Your prescriber may order these tests more often if you take olmesartan and lithium together.

8. Colesevelam

Colesevelam (Welchol) is prescribed to treat high cholesterol. It may also be used to treat high blood glucose (sugar) caused by Type 2 diabetes.

Colesevelam can attach to olmesartan and prevent it from being absorbed normally by your body. This makes olmesartan less effective.

You can minimize this interaction by taking olmesartan at least 4 hours before taking colesevelam.

When should you contact your healthcare team about olmesartan interactions?

Before you start olmesartan, talk to your healthcare team about possible interactions. Give them a list of the medications and OTC products you take. They can review your list and check for interactions.

If you’re already taking olmesartan, contact your prescriber or pharmacist before you start a new medication or supplement. This way, they can check for interactions before they happen.

Finally, contact your prescriber if you develop side effects while taking olmesartan. These could be due to an interaction. Severe side effects like chest pain, shortness of breath, and trouble breathing warrant emergency care.

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Written by:

Alex Brewer, PharmD, MBA

Alex Brewer, PharmD, MBA, is a licensed pharmacist specializing in chronic disease and health and wellness. Upon completing his residency, he worked in the managed care field, conducting medication therapy management and adherence counseling sessions with Medicaid, Medicare, and private insurance patients, before transitioning to a career in medical writing.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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