Potassium is needed for cells to function properly. You get potassium through food. Your kidneys remove excess potassium through the urine to keep a proper balance of this mineral in your body.

If your kidneys are not working well, they may not be able to remove the proper amount of potassium. As a result, potassium can build up in the blood. This buildup can also be due to:

• Addison disease -- Disease in which the adrenal glands do not make enough hormones, reducing the kidneys' ability to remove potassium from the body
• Burns over large areas of the body
• Certain blood pressure lowering drugs, most often angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs)
• Damage to muscle and other cells from certain illicit street drugs, alcohol abuse, untreated seizures, surgery, crush injuries and falls, certain chemotherapies, or certain infections
• Disorders that cause red blood cells to burst (hemolytic anemia)
• Severe bleeding from the stomach or intestines
• Taking extra potassium, such as salt substitutes or supplements
• Tumors

There are often no symptoms with a high level of potassium. When symptoms do occur, they may include:

• Chest pain
• Difficulty breathing
• Nausea or vomiting
• Palpitations (irregular or abnormal-feeling heartbeats)
• Slow, weak, or irregular pulse
• Sudden collapse, when the heartbeat gets too slow or even stops

Your health care provider will perform a physical exam and ask about your symptoms.

Tests that may be ordered include:

• Electrocardiogram (ECG)
• Blood potassium level

Your provider will likely check your blood potassium level and do kidney blood tests on a regular basis if you:

• Have been prescribed extra potassium
• Have long-term (chronic) kidney disease
• Take medicines to treat heart disease or high blood pressure
• Use salt substitutes

You will need emergency treatment if your potassium level is very high, or if you have danger signs, such as changes in your ECG.

Emergency treatment may include:

• Calcium given into your veins (IV) to treat the muscle and heart effects of high potassium levels
• Glucose and insulin given into your veins (IV) to help lower potassium levels long enough to correct the cause
• Kidney dialysis if your kidney function is poor
• Medicines that help remove potassium from the intestines before it is absorbed
• Sodium bicarbonate if the problem is caused by acidosis
• Some diuretics (most often given by vein) that increase the excretion of potassium by your kidneys into your urine

Changes in your diet can help both prevent and treat high potassium levels. You may be asked to:

• Limit or avoid asparagus, avocados, potatoes, tomatoes or tomato sauce, winter squash, pumpkin, and cooked spinach
• Limit or avoid oranges and orange juice, nectarines, kiwifruit, raisins, or other dried fruit, bananas, cantaloupe, honeydew, prunes, and nectarines
• Limit or avoid taking salt substitutes if you are asked to follow a low-salt diet

Your provider may make the following changes to your medicines:

• Reduce or stop potassium supplements
• Stop or change the doses of medicines you are taking, such as ones for heart disease and high blood pressure
• Take a certain type of water pill to reduce potassium and fluid levels if you have chronic kidney failure

Follow your provider's directions when taking your medicines:

• DO NOT stop or start taking medicines without first talking to your provider
• Take your medicines on time
• Tell your provider about any other medicines, vitamins, or supplements you are taking

If the cause is known, such as too much potassium in the diet, the outlook is good once the problem is corrected. In severe cases or those with ongoing risk factors, high potassium will likely recur.

Complications may include:

• Heart suddenly stops beating (cardiac arrest)
• Kidney failure
• Weakness

Contact your provider right away if you have vomiting, palpitations, weakness, or difficulty breathing, or if you're taking a potassium supplement and have symptoms of high potassium.

Hyperkalemia; Potassium - high; High blood potassium

Mount DB. Disorders of potassium balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 17.

Seifter JL. Potassium disorders. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 103.

Updated by: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.