Phosphate supplement (By mouth)


Increases the amount of phosphate in urine. Used to increase the level of acid in urine. Reduces the smell and rash caused by very basic (alkaline) urine.

Brand Name(s)

K-Phos Neutral, K-Phos Original, Phospha 250 Neutral, K-Phos No. 2, Phospho-Soda

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

You should not use this medicine if you have had an allergic reaction to sodium phosphate or potassium phosphate, or if you have infected phosphate stones. You should not use this medicine if you have severe kidney problems, or if you have hyperphosphatemia (too much phosphorus in your blood).

How to Use This Medicine

Tablet, Liquid, Coated Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • Take this medicine with a full (8 ounce) glass of water. Take it at meal times and again at bed time, unless your doctor tells you differently.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Keep all medicine away from children and never share your medicine with anyone.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using blood pressure medicine, such as diazoxide, guanethidine, hydralazine, methyldopa, or rauwolfia alkaloid. Tell your doctor if you are using a corticosteroid medicine, such as a mineralocorticoid or corticotropin, or if you are also using a diuretic ("water pill"), such as spironolactone, triamterene, or Aldactone®. Make sure your doctor knows if you are also using digoxin (Lanoxin®) or a salicylate medicine, such as aspirin.
  • Avoid using antacids that contain aluminum, calcium, or magnesium while you are using a phosphate supplement. These type of antacids include aluminum carbonate, magnesium hydroxide, milk of magnesia, Basalgel®, Gaviscon®, Maalox®, and Rolaids®. Using antacids and phosphate supplements at the same time may cause the phosphate supplements not to work as well.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breast feeding, or if you have heart problems, high blood pressure, or Addison's disease. Tell your doctor if you have severe burns or other serious skin problems, or if you are dehydrated. Make sure your doctor knows if you have myotonia congenita (an inherited disease that affects your muscles).
  • Make sure your doctor knows if you have liver disease, severe kidney problems or swelling in your hands, feet or ankles. Tell your doctor if you have toxemia of pregnancy, hypoparathyroidism (too little activity of the parathyroid gland), acute pancreatitis, or rickets.
  • If you have kidney stones, you may pass old stones as you begin using this medicine.
  • Your doctor will need to check your progress at regular visits while you are using this medicine. Be sure to keep all appointments.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Fast or uneven heartbeat.
  • Seizures.
  • Shortness of breath.

If you notice these less serious side effects, talk with your doctor:

  • Bone or joint pain.
  • Change in how much or how often you urinate.
  • Feeling unusually confused, tired, or weak.
  • Feeling very thirsty.
  • Headache, lightheadedness, or dizziness.
  • Heaviness or weakness in your legs.
  • Mild diarrhea, or loose stools.
  • Muscle cramps.
  • Nausea, vomiting, or stomach pain.
  • Numbness, tingling, or pain in your hands or feet.
  • Swelling in your feet or lower legs, or unusual weight gain.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

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