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Potassium phosphate

Generic Name: potassium phosphate (poe-TAS-ee-um FOS-fate)
Brand Name: K-Phos Original

Potassium phosphate is used for:

Preventing kidney stones. It is also used to increase the effectiveness of certain antibacterial medicines (methenamine mandelate and methenamine hippurate). It may also be used for other conditions as determined by your doctor.

Potassium phosphate is a urinary acidifier. It works by increasing the amount of acid in the urine, which lowers the pH of the urine. This may reduce the growth of some bacteria in the urine and help dissolve calcium kidney stones.

Do NOT use potassium phosphate if:

  • you are allergic to any ingredient in potassium phosphate
  • you have infected kidney stones or severe kidney problems
  • you have decreased urination or are unable to urinate
  • you have high levels of phosphate or potassium in the blood

Contact your doctor or health care provider right away if any of these apply to you.

Before using potassium phosphate:

Some medical conditions may interact with potassium phosphate. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have low blood calcium levels or you are on a potassium-restricted diet
  • if you have a history of heart problems (eg, heart failure), kidney problems, kidney or other urinary stones, certain muscle problems (eg, myotonia congenita, rhabdomyolysis), stomach or bowel problems (eg, inflammation), liver problems, adrenal gland problems (eg, Addison disease), inflammation of the pancreas, or parathyroid problems
  • if you are dehydrated or have rickets, softened or weakened bones, or a urinary tract infection
  • if you have a condition in which your skin is breaking down (eg, severe burns)

Some MEDICINES MAY INTERACT with potassium phosphate. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Aldosterone blockers (eg, eplerenone), aliskiren, angiotensin-converting enzyme (ACE) inhibitors (eg, enalapril), potassium-sparing diuretics (eg, triamterene), or potassium supplements because the risk of high potassium levels, possibly with irregular heartbeat or a heart attack, may be increased
  • Digoxin or salicylates (eg, aspirin) because the risk of their side effects may be increased by potassium phosphate

This may not be a complete list of all interactions that may occur. Ask your health care provider if potassium phosphate may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use potassium phosphate:

Use potassium phosphate as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Potassium phosphate is usually taken with meals and at bedtime. Ask your doctor when you should take potassium phosphate.
  • Do not swallow potassium phosphate whole. Dissolve 2 tablets in 6 to 8 oz (180 to 240 mL) of water. Allow the tablets to dissolve for 2 to 5 minutes or more, if necessary. Stir to be sure the medicine is completely dissolved. If any tablet particles do not dissolve, crush them and stir well.
  • If your doctor has told you to use a different dose, ask your pharmacist how much water to use to dissolve the medicine.
  • Do not take antacids that have aluminum, magnesium, or calcium with potassium phosphate without checking with your doctor or pharmacist.
  • If you miss a dose of potassium phosphate, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use potassium phosphate.

Important safety information:

  • Potassium phosphate may cause dizziness. This effect may be worse if you take it with alcohol or certain medicines. Use potassium phosphate with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • While taking potassium phosphate, the possibility of passing old kidney stones is increased.
  • Check with your doctor before you use a salt substitute or a product that has potassium in it.
  • Lab tests, including kidney function and electrolyte levels (eg, calcium, potassium, phosphorus), may be performed while you use potassium phosphate. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • PREGNANCY and BREAST-FEEDING: It is not known if potassium phosphate can cause harm to the fetus. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using potassium phosphate while you are pregnant. It is not known if this medicine is found in breast milk. If you are or will be breast-feeding while you use potassium phosphate, check with your doctor. Discuss any possible risks to your baby.

Possible side effects of potassium phosphate:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; nausea; stomach pain; vomiting.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bone or joint pain; confusion; decreased urination; dizziness; irregular heartbeat; muscle cramps; numbness, tingling, pain, or weakness in the hands or feet; numbness or tingling around the lips; seizures; severe or persistent diarrhea; shortness of breath; unusual tiredness; unusual weakness or heaviness of the legs.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately.

Proper storage of potassium phosphate:

Store potassium phosphate at room temperature, between 68 and 77 degrees F (20 and 25 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep potassium phosphate out of the reach of children and away from pets.

General information:

  • If you have any questions about potassium phosphate, please talk with your doctor, pharmacist, or other health care provider.
  • Potassium phosphate is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take potassium phosphate or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about potassium phosphate. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to potassium phosphate. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using potassium phosphate.

Review Date: November 3, 2016

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

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