High potassium (hyperkalemia): Causes, prevention and treatment

high potassium
If you have kidney disease, your kidneys cannot remove the extra potassium in your blood. Learn how to control, prevent and treat high potassium (hyperkalemia) levels.
Medically reviewed by
AKF's Medical Advisory Committee
Last updated
June 12, 2024

What is high potassium, or hyperkalemia?

Everyone needs potassium to survive. Potassium is a mineral and an electrolyte. It helps your muscles work, including the muscles that control your heartbeat and breathing. Potassium comes from the food you eat.

Your body uses the potassium it needs. Your kidneys remove the extra potassium from your blood. When you have kidney disease, your kidneys cannot remove extra potassium in the right way, and too much potassium can stay in your blood.

When you have too much potassium in your blood, it is called hyperkalemia, or high potassium. Having too much potassium in your blood can be dangerous. Hyperkalemia can even cause a heart attack or death! Unfortunately, many people do not feel symptoms of hyperkalemia until it is too late and their heart health worsens.

If you have kidney disease, you are at risk for high potassium. This means:  

  1. Your kidneys cannot remove the extra potassium in your blood. 
  2. Instead of leaving your body through your urine, the extra potassium in your blood travels through your kidneys and back into your bloodstream.  
  3. Over time, more and more potassium can build up in your blood.   

Visit our Beyond Bananas  page to learn more about managing your potassium levels. 

What causes high potassium?

When you have kidney disease, some of the most common causes of high potassium are:  

  • Eating high-potassium foods  
  • Using a salt substitute that contains potassium (they have around 800 mg of potassium per ¼ teaspoon!)  
  • Constipation  
  • High blood sugars  
  • Missing dialysis treatments  
  • Taking some medicines or herbal supplements*  
  • Some blood pressure medicines (like ACE inhibitors and ARBs) can raise the level of potassium in your body  

*Always talk with your doctor before taking any herbal supplement that could interact with your medicines or medical conditions. 

What are the symptoms of high potassium?

Many people do not feel symptoms of high potassium. Having too much potassium in your blood can be dangerous. It can even cause a heart attack.

If you do feel symptoms, some of the most common are:

  • Feeling tired or weak
  • Feeling sick to the stomach (nausea)
  • Muscle pains or cramps
  • Trouble breathing, unusual heartbeat, chest pains

If you have trouble breathing or think there could be a problem with your heart, call 911 for emergency help.

What are the complications of high potassium?

Having too much potassium in your blood can be dangerous. Potassium affects the way your heart's muscles work. When you have too much potassium, your heart may beat irregularly, which in the worst cases can cause heart attack.

If you think you are having a heart attack, call 911 for emergency help.

Some of the most common signs of heart attack are:

  • Feelings of pressure, pain, or squeezing in your chest or arms
  • Stomach pain or nausea
  • Shortness of breath
  • Breaking into a cold sweat
  • Sudden feelings of dizziness


Keep your potassium in balance

Learn how to keep your potassium levels in balance.

What are the tests for high potassium?

The only way to know for sure if your potassium level is healthy is to have a blood test. The test measures how much potassium is in your blood. However, blood tests only show how much potassium is in your blood at the moment you had the test, not over an entire week or month. So, it is important to talk to your doctor about how you can best manage your potassium levels over time and if any of your medicines could affect your levels. For example, some blood pressure medicines, like RAAS inhibitors could raise your potassium levels. ACE inhibitors and ARBs are common RAAS inhibitors. 

The blood test is like many other blood tests that you may be familiar with. A small needle is placed into a vein on your arm and your blood is drawn out into a tube. The blood is sent to lab to be tested. 

Potassium may be called something else in your test results. If you do not see "potassium," look for either: 

  • Serum potassium 
  • K 

A potassium of higher than 5.2 millimoles per liter (mmol/L) is usually considered high but your doctor or lab might use slightly different numbers. Talk to your doctor about what your test results mean. 

Because very high potassium (higher than 6.0 mmol/L) can be dangerous, your doctor or nurse may contact you first if your results are unusually high. In this case, they may ask you to go to an emergency room or hospital. 

What are the treatments for high potassium?

There are two ways to help manage high potassium: through what you eatand/or with medicine. 

Follow a kidney-friendly eating plan 

You can help control high potassium through what you eat. Certain foods have more potassium in them than others. To manage your potassium intake, you need to know how much potassium is in your food and drinks.  

Talk to your doctor or dietitian about how much potassium you should have and how you cancontrol how much potassium you eat. Your dietitian can recommend foods that are low inpotassium that you can eat instead of foods that are high in potassium.  

Visit Kidney Kitchen® for kidney-friendly recipes, nutrient information, and guides to help you find foods that will help you manage your potassium. 

Potassium binders

Medicines for high potassium are called potassium binders. A potassium binder works by sticking to the potassium in your body and preventing some of it from being taken into your bloodstream. This helps to keep potassium from building up in your blood. Potassium binders allow you to eat a wider variety of healthy food with less worry about your potassium levels. The medicine is a powder, which you can take by mixing it with water and drinking. Talk to your doctor about whether a potassium binder could be an option for you. 

Manage your potassium levels with what you eat and treatment

Download this guide to learn the amount of potassium in many common foods and know which foods are considered low, medium and high sources of potassium.

WATCH: RAAS inhibitors, potassium binders and the diet connection

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