Hypokalemia is a lower-than-normal amount of potassium in the blood.

Alternative Names

Potassium - low; Low blood potassium


Potassium is needed for cells, especially nerve and muscle cells, to function properly. You get potassium through food. The kidneys remove excess potassium in the urine to keep a proper balance of the mineral in the body.

Hypokalemia is a metabolic disorder that occurs when the level of potassium in the blood drops too low.

Possible causes of hypokalemia include:


A small drop in potassium usually doesn't cause symptoms. However, a big drop in the level can be life threatening.

Symptoms of hypokalemia include:

Exams and Tests

Your health care provider will take a sample of your blood to check potassium levels.

Other tests might include:


Mild hypokalemia can be treated by taking potassium supplements by mouth. Persons with more severe cases may need to get potassium through a vein (intravenously).

If you need to use diuretics, your doctor may switch you to a form that keeps potassium in the body (such as triamterene, amiloride, or spironolactone).

One type of hypokalemia that causes paralysis occurs when there is too much thyroid hormone in the blood (thyrotoxic periodic paralysis). Treatment lowers the thyroid hormone level, and raises the potassium level in the blood.

Outlook (Prognosis)

Taking potassium supplements can usually correct the problem. In severe cases, without proper treatment a severe drop in potassium levels can lead to serious heart rhythm problems that can be fatal.

Possible Complications

In severe cases, patients can develop paralysis that can be life threatening. Hypokalemia also can lead to dangerous irregular heartbeat. Over time, lack of potassium can lead to kidney damage (hypokalemic nephropathy).

When to Contact a Medical Professional

Call your health care provider if you have been vomiting or have had excessive diarrhea, or if you are taking diuretics and have symptoms of hypokalemia.


Eating a diet rich in potassium can help prevent hypokalemia. Foods high in potassium include:


Mount DB, Zandi-Nejad K. Disorders of potassium balance. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 15.

Seifter JL. Potassium disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 118.

Review Date: 5/29/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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