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Hypophosphatemia (Low Level of Phosphate in the Blood)


James L. Lewis, III

, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Last full review/revision Apr 2020| Content last modified Apr 2020

In hypophosphatemia, the level of phosphate in blood is too low.

(See also Overview of Electrolytes and Overview of Phosphate's Role in the Body.)

Phosphate is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood, but the majority of phosphate in the body is uncharged.

Hypophosphatemia may be

  • Acute
  • Chronic

Acute hypophosphatemia

In acute hypophosphatemia, the phosphate level in blood suddenly falls dangerously low. Because the body uses large amounts of phosphate during recovery from certain disorders, acute hypophosphatemia may occur in people recovering from the following conditions:

This sudden drop in phosphate level may result in an abnormal heart rhythm and even death.

Chronic hypophosphatemia

In chronic hypophosphatemia, the phosphate level in blood becomes low over time. Chronic hypophosphatemia usually develops because too much phosphate is excreted. Causes include the following:

  • Hyperparathyroidism
  • Chronic diarrhea
  • Use of diuretics for a long time
  • Use of large amounts of aluminum-containing antacids for a long time
  • Use of large amounts of theophylline (used to treat asthma)

Did You Know...

  • Some people who survived concentration camps died because their already low phosphate level suddenly fell when they began eating a normal diet, a phenomenon called refeeding syndrome.


Symptoms of hypophosphatemia occur only when the phosphate level in blood becomes very low. Muscle weakness develops, followed by stupor, coma, and death.

In mild chronic hypophosphatemia, the bones can weaken, resulting in bone pain and fractures. People may become weak and lose their appetite.


  • Measurement of phosphate levels in the blood

Hypophosphatemia is diagnosed when blood tests show that the level of phosphate in the blood is low. Doctors do other tests to identify the cause if it is not readily apparent.


  • Increase phosphate intake

Drugs that reduce the phosphate level are stopped.

If hypophosphatemia is mild and causes no symptoms, drinking low-fat or skim milk, which provides a large amount of phosphate, may help. Or people can take phosphate by mouth, but doing so usually causes diarrhea.

If hypophosphatemia is very severe or if phosphate cannot be taken by mouth, phosphate may be given by vein (intravenously).

Drugs Mentioned In This Article

Generic Name Select Brand Names
theophylline ELIXOPHYLLIN

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