Losartan and eating bananas: what you need to know

If you’re taking losartan (brand name Cozaar), you may have already been warned about the risk that this medication, combined with other factors, can raise blood potassium levels (DailyMed, 2018). And while other medications that alter potassium levels may be easy to avoid, it might be harder to navigate which foods you should and shouldn’t eat when taking losartan, specifically common potassium-rich foods like bananas. Here’s what you need to know about losartan and eating bananas.

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Losartan belongs to a class of medications called angiotensin receptor blockers (ARBs), which are most commonly used to treat high blood pressure (hypertension), reduce the risk of stroke, and reduce the chance of kidney problems in people with diabetes (DailyMed, 2020). These medications act on the system that controls the balance of water and electrolytes in the body, which means they may potentially cause high potassium levels (Raebel, 2011).

In patients treated with an ARB or another common blood pressure medication class known as ACE inhibitors, the incidence of excessively high potassium levels (hyperkalemia) is approximately 3.3% (Yusef, 2008). But certain people are at a higher risk of developing this condition. For people with normal kidney function, these medications raise potassium levels only slightly (Phillips, 2007).  

The risk of hyperkalemia is higher in patients with kidney problems, including those with chronic kidney disease or diabetes, or those taking other medications that encourage the body to retain potassium, such as potassium-sparing diuretics and non-steroidal anti-inflammatory drugs (NSAIDs) (Phillips, 2007).

Research on ARBs and potassium intake is limited. Some health institutions warn against using salt substitutes while taking losartan. These products may use potassium chloride, which increases the risk of potassium levels in the blood becoming too high when combined with ARBs because these medications reduce your body’s ability to get rid of extra potassium (NHS, 2018; Weir, 2010). 

Hyperkalemia, a condition that happens when blood potassium levels are too high, can be mild or serious, potentially causing fatal cardiac arrhythmias (irregular heartbeats)(Simon, 2020).

So what about regular foods that might contain naturally high levels of potassium? Eating potassium-rich foods like bananas may be safe for people taking losartan who don’t have kidney problems. Increasing dietary potassium was deemed safe by one study that looked at patients on ARBs or ACE inhibitors who had regular kidney function (Malta, 2016). 

The researchers increased participants’ potassium intake through fruits and veggies over a four-week period and compared them with a placebo group (who didn’t eat extra potassium-containing foods). And while they were packing in the potassium (consuming between 1000-4000 mg of potassium daily through their diets), blood potassium levels were not significantly increased in comparison with the control group. 

Overall, researchers concluded that eating a diet high in potassium did not put these participants at risk for hyperkalemia (Malta, 2016).

It’s important to note, though, that all the people who took part in the study had normal kidney function. And since losartan may be used by people with type 2 diabetes and high blood pressure to slow the progression of kidney disease (DailyMed, 2020), it’s important to remember that this study does not confirm the safety of eating a diet high in potassium-rich foods for people with impaired kidney function.

If you or someone you know has chronic kidney disease or diabetes, you may already know that losartan can be prescribed to slow down the damage to the kidneys (FDA, 2018). Since the kidneys play an important role in regulating the amount of potassium in your blood, when they’re not working properly, it can result in too much potassium building up in the body (National Kidney Foundation, 2020).

If you’re taking losartan and you have a kidney condition or diabetes, you may need to watch how much potassium you’re getting through your diet. Your healthcare provider may monitor your blood potassium levels. If your blood potassium stays low while you take this medication, your healthcare provider might not limit your dietary potassium intake. But if your blood potassium hits certain ranges, you may be asked to monitor your potassium intake (Han, 2013).

The first foods to be limited are those with very high levels of potassium (>500 mg per serving), including white potatoes, sweet potato, most beans, and tomato sauce or paste. High potassium foods that have 250-500 mg per serving may also be limited. That includes many common foods, such as (Han, 2013):

• Vegetables like acorn squash, artichokes, butternut squash, corn, parsnips, pumpkin, spinach, and tomato

• Fruits such as apricots, avocados, bananas, cantaloupes, dried fruit (especially dried apricot), honeydew, kiwi, mangoes, nectarines, and oranges 

• Fruit juices such as grapefruit juice, orange juice, tomato juice, and prune juice, as well as sports drinks, dried beans, lentils, instant coffee, yogurt, and milk 

Eating bananas with losartan depends on your individual state of health and your blood potassium levels, but it’s possible that your healthcare provider may ask you to limit your intake. If some of your favorite foods are high in potassium, talk to your healthcare provider about whether it’s possible to adjust your diet to include moderate amounts of these foods while taking this blood pressure medication.

Losartan is the chemical name of a drug commonly sold under the brand name Cozaar. It belongs to a class of medications called angiotensin receptor blockers (ARBs) and is approved by the U.S. Food and Drug Administration (FDA) to treat high blood pressure (hypertension), stroke risk, and kidney problems from diabetes (DailyMed, 2020).

It may also be used off-label after a heart attack to help individuals with heart failure who cannot tolerate ACE inhibitors and treat non-diabetic kidney disease (UpToDate, n.d.). Losartan is available both as generic losartan potassium tablets and as brand name Cozaar. Tablets are available in 25 mg, 50 mg, and 100 mg dosages. 

In people with high blood pressure, the most common side effects of losartan include dizziness, stuffy nose, and back pain. In individuals with type 2 diabetes taking losartan to manage kidney problems, the most common side effects include chest pain, diarrhea, high blood potassium, low blood pressure, low blood sugar, and tiredness (FDA, 2018). 

Although less common, it is possible that people taking losartan who already have kidney problems will see a decrease in kidney function. Call your healthcare provider immediately if you notice swelling of the hands, feet, or ankles or experience unexplained sudden weight gain (FDA, 2018).

Pregnant women should not take losartan. That means you should discontinue taking losartan if you find out that you are pregnant. This medication may cause injury or death to the fetus if it’s taken during the second or third trimesters (last six months of the pregnancy) (DailyMed, 2020). If you take this medication and become pregnant, see your healthcare provider to discuss alternative therapies for managing your blood pressure during pregnancy.

Serious side effects are possible with losartan and may include severe allergic reaction—including hives, itching, rash, and trouble breathing—low blood pressure, and changes in kidney function (UpToDate, n.d.). But more potential side effects may exist, so it’s important to talk to your healthcare provider or pharmacist about drug information you need to know before taking this medication.

Losartan may also cause serious adverse effects when combined with certain medications, which is why you should inform a medical professional about what other drugs or supplements you’re taking before starting. Combining losartan with medications that raise blood levels of potassium may result in hyperkalemia since your body may not clear this mineral effectively (DailyMed, 2020). 

Lithium, a mood stabilizer that’s used to treat bipolar disorder, may build up in your system and cause lithium toxicity when combined with ARBs such as losartan (DailyMed, 2020).

Non-steroidal anti-inflammatory drugs (NSAIDs) are drugs commonly used to treat inflammation and pain. Over-the-counter options, including common painkillers like ibuprofen and naproxen. Combining these drugs with losartan may cause kidney problems. NSAIDs also decrease this medication’s ability to lower blood pressure. If you feel that you need to take a medication to ease pain, get medical advice about what you can safely take (DailyMed, 2020).

ACE inhibitors (such as lisinopril, captopril, and enalapril) are prescription drugs that also lower blood pressure. Like ARBs, they act on the renin-angiotensin-aldosterone system (RAAS). In general, more than one medication that acts on the RAAS should not be taken at one time. When combined with ARBs such as losartan, these medications may increase your risk of low blood pressure, high potassium levels, fainting, and worsening kidney function. It may even cause kidney failure (DailyMed, 2020).

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

October 12, 2020

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.