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Hyperkalemia (High Level of Potassium in the Blood)

by James L. Lewis, III, MD

In hyperkalemia, the level of potassium in blood is too high.

  • A high potassium level has many causes, including kidney disorders, drugs that affect kidney function, and consumption of too much supplemental potassium.

  • Usually, hyperkalemia must be severe before it causes symptoms, mainly abnormal heart rhythms.

  • Doctors usually detect hyperkalemia when blood tests or electrocardiography is done for other reasons.

  • Treatment includes reducing consumption of potassium, stopping drugs that may cause hyperkalemia, and using drugs to increase potassium excretion.

The body needs potassium for nerve and muscle cells to function, but too much potassium can also interfere with function (see Overview of Potassium).

Usually, hyperkalemia results from several simultaneous problems, including the following:

  • Kidney disorders (such as kidney failure) that prevent the kidneys from excreting enough potassium

  • Drugs that prevent the kidneys from excreting normal amounts of potassium (a common cause of mild hyperkalemia)

  • A diet high in potassium

  • Treatments that contain potassium

The most common cause of mild hyperkalemia is the use of drugs that decrease blood flow to the kidneys or prevent the kidneys from excreting normal amounts of potassium. Kidney failure can cause severe hyperkalemia on its own. Addison disease can also cause hyperkalemia.

Hyperkalemia can develop after a large amount of potassium is released from the cells. The rapid movement of potassium from cells into blood can overwhelm the kidneys and result in life-threatening hyperkalemia.

What Makes the Potassium Level Increase?



Drugs or Other Circumstances

Increased consumption

A diet containing potassium-rich foods

Potassium supplements

Intravenous treatments that contain potassium, such as total parenteral nutrition and blood transfusions

Decreased excretion in urine

Kidney failure


Angiotensin-converting enzyme (ACE) inhibitors

Angiotensin-receptor blockers

Cyclosporine (used to prevent rejection of organ transplants)

Diuretics that help the kidneys conserve potassium, such as eplerenone, spironolactone, and triamterene

Nonsteroidal anti-inflammatory drugs

Tacrolimus (used to prevent rejection of organ transplants)

Trimethoprim (an antibiotic)

Release of potassium from cells

Burns if severe

Crush injuries

Muscle breakdown (rhabdomyolysis)

Diabetes mellitus (especially ketoacidosis)

Metabolic acidosis


Cancer chemotherapy

Exercise if strenuous and prolonged

Symptoms and Diagnosis

Mild hyperkalemia causes few, if any, symptoms. Sometimes, people may develop muscle weakness. When hyperkalemia becomes more severe, it can cause abnormal heart rhythms. If the level is very high, the heart can stop beating.

Usually, hyperkalemia is first detected when routine blood tests are done or when a doctor notices certain changes on an electrocardiogram. To identify the cause, doctors determine which drugs people are taking and do blood tests to check for evidence of diabetes mellitus, acidosis, muscle breakdown or kidney disorders.


For mild hyperkalemia, reducing consumption of potassium or stopping drugs that prevent the kidneys from excreting potassium may be all that is needed. If the kidneys are functioning, a diuretic that increases potassium excretion may be given. If needed, a resin that absorbs potassium from the digestive tract and passes out of the body in the stool can be given by mouth or enema.

For moderate to severe hyperkalemia, the potassium level must be reduced immediately. Calcium is given intravenously to protect the heart but does not lower the potassium level. Then insulin and glucose are given. They move potassium from blood into cells, thus lowering the potassium level in blood. Albuterol (used mainly to treat asthma) may be given to help lower the potassium level. It is inhaled.

If these measures do not work or if people have kidney failure, dialysis may be necessary to remove the excess potassium.

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