6 Losartan Interactions You Should Know About

If you have high blood pressure, chances are you may be taking losartan (Cozaar). After all, losartan is one of the most commonly prescribed medications in the U.S. You might also be taking other medications, over-the-counter (OTC) products, and supplements with it. But is it safe to combine them?

Common OTC pain relievers, like ibuprofen (Advil, Motrin), can interact with losartan. And potassium supplements can cause problems, too. Some losartan interactions can be avoided with safer alternatives. Others may need to be monitored closely. Let’s review a few possible losartan interactions you should know about.

1. Medications that raise potassium levels

Potassium is an electrolyte that’s commonly found in the body. Medical conditions, your diet, and even medications can cause higher potassium levels than normal. This is called hyperkalemia. Hyperkalemia can cause muscle cramps, weakness, and tingling or numbness.

Losartan can increase potassium levels on its own. Combining it with other medications that increase potassium can make hyperkalemia more likely. Examples include potassium supplements like potassium chloride (Klor-Con) and potassium-sparing diuretics like eplerenone (Inspra) and spironolactone (Aldactone).

Your healthcare provider will monitor your potassium levels during treatment. You may not realize your potassium is too high without a blood test. But if you develop symptoms, it’s important to let them know right away. 

2. Lithium

Lithium (Lithobid) is a medication used to treat bipolar disorder and other mental health conditions. It requires careful monitoring by your healthcare provider. That’s because too much lithium can cause side effects. And if your lithium levels get too low, it won't work as well.

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Lithium is mostly removed from your body by the kidneys. Taking it with losartan can lead to higher amounts of lithium staying in your body. This can result in a potentially life-threatening condition called lithium toxicity. 

Your healthcare provider will monitor your lithium levels during treatment. If necessary, they can adjust your lithium dosage. Let them know if you develop confusion, blurry vision, or muscle weakness. This could be a sign of lithium toxicity.

3. NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to treat pain and fever. Many are available both OTC and as a prescription medication. Some examples include ibuprofen and naproxen (Aleve, Naprosyn). 

NSAIDs can be hard on the kidneys, especially for older adults and for people with kidney disease. Losartan can help protect the kidneys, but it can also affect kidney function in some people.

Combining NSAIDs with losartan can increase the risk of kidney problems. This is especially the case if you’re older, taking diuretics, and/or already have kidney problems.

Lastly, NSAIDs like ibuprofen have been shown to increase blood pressure. So, your blood pressure may not be as controlled while taking losartan. Because of this, some experts recommend avoiding NSAIDs if you have high blood pressure.

Talk to your healthcare provider about which pain relievers are safe for you. They can suggest safer alternatives that may be more compatible with losartan.

4. ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are another first-choice medication for high blood pressure. Examples include lisinopril (Zestril), enalapril (Vasotec), and benazepril (Lotensin). Losartan, on the other hand, is an angiotensin II receptor blocker (ARB).

ACE inhibitors work along the same pathway as ARBs. You’re typically prescribed one or the other — not both. That’s because combining them can cause more side effects without additional benefits. Your healthcare provider will typically avoid this combination.

5. Aliskiren

Aliskiren (Tekturna) is another blood pressure medication. It also works along the same pathway as ACE inhibitors and ARBs. Similar to the interaction above, you may experience more side effects without added benefits if it’s combined with losartan. 

For this reason, it’s recommended to avoid taking aliskiren with losartan. This is especially the case if you also have diabetes or kidney problems.

6. Entresto

Entresto (sacubitril/valsartan) is a newer medication used to treat heart failure. It’s a combination pill that contains an ARB called valsartan. Since valsartan and losartan are both ARBs, it’s not recommended to take them together. So, this combination should be avoided.

When should I contact my healthcare provider about a losartan interaction?

If you’re ever unsure about a losartan interaction, contact your healthcare provider. Chances are, they’re already aware of the interaction.

Not all interactions are serious or need to be avoided. In some cases, they can be managed through dosage adjustments and monitoring. Even so, let them know if you’re experiencing new or worsening side effects. This may be more likely to happen when starting or stopping a medication or after dosage changes.

Make sure you provide your current medication list to your healthcare provider and pharmacist. This includes any OTC products and supplements. This can help them identify potential interactions ahead of time. 

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Written by:

Timothy Aungst, PharmD

Timothy Aungst, PharmD, has worked in pharmacy practice for the past decade with different roles and responsibilities. He has served as an associate professor of pharmacy practice for almost a decade, a clinical pharmacist in outpatient cardiology management, and now in home healthcare.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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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