Care During Chemotherapy and Beyond

Hypophosphatemia (Low Phosphate)

What Is Hypophosphatemia?

Hypophosphatemia may be described as low levels of inorganic phosphate in the blood.

Phosphate, or phosphorous, is similar to calcium, and is found in your teeth and bones. You need vitamin D in order to absorb phosphate. The kidneys excrete (get rid of) phosphate from our bodies.

The normal range for phosphorous is 2.5-4.5 mg/dL.  Normal values may vary from laboratory to laboratory.

Hypophosphatemia is also seen in people who have:

  • Poor absorption of phosphate - your body is not absorbing the phosphate
  • If you had stomach surgery
  • If you are lacking in Vitamin-D (which is needed to absorb phosphate)
  • The absorption of phosphate is being blocked by aluminum hydroxide found in laxatives such as Maalox or Amphogel.
  • Certain medications prevent phosphate from being absorbed.
  • Problems with your blood electrolyte levels, such as low blood magnesium (needed to absorb phosphorous), or high blood calcium (which binds to the phosphorous, making it lower than normal).
  • Certain breathing problems can lead to hypophosphatemia
  • Low blood phosphate levels may also be the result of an increased loss of bicarbonate from your urine. This may be a result of:
  • Kidney dysfunction or damage- This form of damage to the kidneys does not cause failure (when your phosphate levels will be higher than normal), but it causes you to excrete or get rid of too much phosphorous through the kidney
  • Water pills or diuretics
  • Endocrine problems - such as a hyper parathyroid or thyroid gland, poorly controlled diabetes
  • Alcoholism - drinking too much alcohol on a regular basis
  • Rickets
  • If you are being treated for severe, uncontrolled diabetes (or elevated blood glucose)- phosphate likes to follow or accompany glucose into the cells, so you may have severely low blood phosphorous levels following this treatment

Symptoms of Hypophosphatemia:

  • Signs of hypophosphatemia include a lower than normal blood phosphate level. Other electrolyte values are likely to be affected, depending on your disease. There are no symptoms of hypophosphatemia, unless the values are critically low.  Then you may notice trouble breathing or respiratory problems, confusion, irritability, or coma. These all may occur with phosphorous levels of 0.1-0.2 mg/ dL.
  • You may not know that your blood phosphate levels are lower than normal, if they are not life-threateningly low. If your phosphorous levels are below 1.0 mg/dL, your tissues may have more trouble connecting hemoglobin with oxygen - which is critical for breathing. You may become mild to moderately short of breath.
  • The symptoms that you notice, with lowered phosphate levels, are due to the disease that is causing this abnormality. If the disease itself is corrected, and with phosphorous supplementation, your blood phosphorous levels should return to the normal range and your hypophosphatemia will go away.

Things You Can Do About Hypophosphatemia:

  • Follow the recommended diet. Depending on the cause of your low blood phosphorous levels, your healthcare provider may suggest that you follow a certain diet. Discuss this with your healthcare provider.   
  • Make sure you tell your doctor, as well as all healthcare providers, about any other medications you are taking (including over-the-counter, vitamins, or herbal remedies).  These can cause interactions with other medications.
  • Remind your doctor or healthcare provider if you have a history of diabetes, liver, kidney, or heart disease.
  • Keep yourself well hydrated. Drink two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
  • If you experience symptoms or side effects, especially if severe, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are effective in managing such problems.
  • Keep all your appointments.

Drugs That May Be Prescribed by Your Doctor:

There are few medications prescribed specifically for low blood phosphate levels. The treatment of your low blood phosphate levels is to identify the underlying cause, and to treat that condition. 

  • Electrolytes - your blood electrolyte levels are most likely low. Therefore, your healthcare provider may suggest magnesium or Vitamin D supplements, if your phosphorous is low. You may also be ordered a medication to lower your blood calcium levels, if it is elevated.
  • Phosphate supplementation - Can be either intravenous (IV) with extremely low levels, or it can be by mouth.

When to Contact Your Doctor or Health Care Provider:

  • Confusion, changes in your mental state, irritable behavior.
  • New pain in your muscles.
  • Nausea that interferes with your ability to eat, and is unrelieved by any prescribed
  • Vomiting (vomiting more than 4-5 times in a 24 hour period).
  • Diarrhea (4-6 episodes in a 24-hour period), unrelieved with taking anti-diarrhea medication and diet modification.
  • Severe constipation, unrelieved by laxatives, lasting 2 to 3 days.

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Note:  We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice. is designed to provide the latest information about chemotherapy to patients and their families, caregivers and friends. For information about the 4th Angel Mentoring Program visit