SPS (Sodium Polystyrene Sulfonate) - Oral

What Is SPS?

SPS (sodium polystyrene sulfonate) is an oral medication that treats hyperkalemia, meaning it lowers potassium levels that are too high. The drug is also known as a cation exchange resin because it works by absorbing potassium ions in exchange for sodium ions in the intestine.

Sodium polystyrene sulfonate is available as a liquid or solution under Kionex and SPS brand names and as a powder under the brand name Kalexate. The brand name Kayexalate is no longer available. The powder form must be mixed with water or syrup to form a thick liquid before taking it by mouth.

Sodium polystyrene sulfonate is not available over the counter (OTC). A licensed healthcare provider will need to prescribe it for you.

Drug Facts

Generic Name: Sodium polystyrene sulfonate

Brand Name(s): SPS, Kalexate, Kionex

Drug Availability: Prescription

Administration Route: Oral, Rectal

Therapeutic Classification: Exchange resin

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Sodium polystyrene sulfonate

Dosage Form(s): Powder, suspension

What Is SPS Used For?

The Food and Drug Administration (FDA) approved sodium polystyrene sulfonate to treat hyperkalemia or high potassium levels. Potassium is an electrolyte essential for our bodies to function correctly.

Potassium levels are measured in milliequivalents per liter (mEq/L). A typical range for potassium is 3.5 to 5 milliequivalents per liter. Levels higher than this range, and specifically higher than 5.5 milliequivalents per liter, can lead to dangerous and abnormal heart rhythms (or arrhythmias), which can be fatal.

Sodium polystyrene sulfonate moves through your digestive tract releasing sodium, another electrolyte. The medicine absorbs excess potassium and removes it from your body in exchange for that sodium.

SPS (Sodium Polystyrene Sulfonate) Drug Information: A person with kidneys showing

Verywell / Dennis Madamba

How to Take SPS

Sodium polystyrene sulfonate comes as a bottle of powder or a liquid. The powder is prepared by mixing a small amount with water or syrup to form a thick liquid taken by mouth. Depending on how high your potassium levels are, you may take this drug anywhere from one to four times a day. If you are using the powder form, only prepare one dose at a time. After the powder is mixed with water or syrup, it’s only good for 24 hours.

The suspension can be taken by mouth or rectally as an enema. Shake the suspension well before each use. Take your medication as prescribed by your healthcare provider.

If you take other medications by mouth, take them at least three hours before or three hours after you take sodium polystyrene sulfonate. It can bind with other drugs in the digestive tract and remove them before they’re able to do their job in your body.

Storage

Store sodium polystyrene sulfonate powder and suspension at room temperature (68 F to 77 F) with the lid on. Do not mix the powder with liquid until you’re ready to take your dose, as it’s only good for 24 hours after mixing.

If you’re traveling by plane, keep the medication in your carry-on luggage in case your checked luggage goes missing.

How Long Does SPS Take to Work?

Sodium polystyrene sulfonate may take hours or days to lower your potassium levels, depending on how high they are. Ask your healthcare provider if you have questions about your potassium level, as it should be regularly monitored while you’re on this medication. This is also why sodium polystyrene sulfonate may not be the best choice for lowering potassium if it is emergently high.

What Are the Side Effects of SPS?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

The side effects caused by SPS are most commonly gastrointestinal, particularly with higher or more frequent dosing. These include:

  • Loss of appetite
  • Nausea
  • Vomiting
  • Constipation
  • Diarrhea

Severe Side Effects

Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms include:

  • Hypokalemia: Sodium polystyrene sulfonate has the potential to lower your potassium level outside of the normal range, which can also lead to dangerous abnormal heart rhythms. Your level should be monitored regularly while you’re taking this medicine.
  • Colonic necrosis and perforation: Colonic necrosis occurs when a part of your colon (large intestine) dies due to cell damage. This can lead to perforation, which is a hole forming in the intestinal wall. These rare side effects are most common in people with pre-existing intestinal disease or kidney disease.
  • Fecal impaction: This happens when a stool hardens so much that you can’t push it out, and it gets stuck in your intestines. Removing it may require medications or sometimes surgery.
  • Other electrolyte changes: Sodium polystyrene sulfonate is not perfect at only absorbing potassium and may also decrease levels of other electrolytes, such as calcium or magnesium, or increase sodium levels.

Long-Term Side Effects

If you experience severe side effects, such as fecal impaction or intestinal perforation, the treatment for these conditions may extend past when you stop taking sodium polystyrene sulfonate. But the medicine itself does not have lasting side effects.

Report Side Effects

SPS may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much SPS Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (powder, suspension):
    • For treatment of hyperkalemia:
      • Adults—15 grams (4 level teaspoons) one to four times a day.
      • Children and infants—Dose is based on the potassium blood level and must be determined by your doctor.

Modifications

There have been no adequate studies to determine sodium polystyrene sulfonate safety during pregnancy or while breastfeeding. Since sodium polystyrene sulfonate stays in your digestive tract and is not absorbed into your bloodstream, it is unlikely to cause harm to your fetus or newborn. Nevertheless, it should only be used in pregnancy or when nursing if needed.

Caution should be used when giving sodium polystyrene sulfonate to children and newborns because it can become impacted (stuck) in their digestive tracts. It should not be given to newborns orally. Use cautiously when giving to children or newborns rectally.

Missed Dose

If you forget to take a dose of sodium polystyrene sulfonate, you can take it as soon as you remember. If you are closer to your next dose than the dose you missed, go ahead and skip the missed dose and wait for your next scheduled one. For example, if you usually take sodium polystyrene sulfonate at 9 a.m. and 9 p.m., and you remember at 5 p.m. that you forgot your morning dose, wait and take your next dose that night at 9 p.m. Do not double up doses to make up for missed ones.

Overdose: What Happens If I Take Too Much SPS?

Taking too much sodium polystyrene sulfonate can cause your potassium or other electrolytes, like calcium or magnesium, to decrease to dangerously low levels. Signs and symptoms may include:

  • Confusion
  • Irritability
  • Muscle weakness or loss of muscle control.

You should call 911 or go to the emergency room if you experience these, as you will likely need medical treatment to correct your electrolyte levels and remove the sodium polystyrene sulfonate from your system.

What Happens If I Overdose on SPS?

If you think you've taken too much sodium polystyrene sulfonate or someone else in your household swallows sodium polystyrene sulfonate, call a healthcare provider or contact the Poison Control Center (800-222-1222).

If you experience or someone else experiences the signs of an overdose, call 911.

Precautions

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It is very important that your doctor check you or your child closely to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Hypokalemia (low potassium in the blood) may occur while you are using this medicine. Check with your doctor right away if you have confusion, dry mouth, increased thirst, irregular heartbeat, irritability, muscle cramps, nausea or vomiting, or trouble breathing.

This medicine may cause a serious stomach or bowel problem, called intestinal necrosis. This is more likely to occur if you have a history of bowel disease, bowel surgery, low blood volume, kidney problems or if you take sorbitol together with this medicine. Tell your doctor right away if you or your child have severe constipation, severe stomach pain, bloody, black, or tarry stools, or vomit blood or a material that looks like coffee grounds.

Tell your doctor if you have unexplained weight gain or edema (fluid retention or body swelling) while using this medicine.

This medicine may cause lung or breathing problems (eg, bronchitis, bronchopneumonia) when you inhale its powder form. It may also increase your risk of having aspiration. Take this medicine in an upright position to prevent this. Talk to your doctor if you have questions.

If you are taking aluminum or magnesium-containing antacids or laxatives, talk to your doctor first before using them together with sodium polystyrene sulfonate. These medicines may keep sodium polystyrene sulfonate from working properly and may cause serious side effects.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take SPS?

The following are circumstances in which sodium polystyrene sulfonate should not be used:

  • People with hypokalemia (low potassium levels)
  • A history of hypersensitivity to polystyrene sulfonate resins (like SPS)
  • Obstructive bowel disease as this can increase the likelihood of constipation and fecal impaction
  • Oral administration in infants as this can also increase the risk of impaction (the drug getting stuck) in the intestine

What Other Medications May Interact With Kayexalate?

Other medications that may interact with sodium polystyrene sulfonate include:

  • Antacids and laxatives: Antacids such as TUMS (calcium carbonate) and Gaviscon (aluminum hydroxide and magnesium carbonate), plus laxatives such as Milk of Magnesia (magnesium hydroxide) or Citroma (magnesium citrate), can interfere with sodium polystyrene sulfonate's ability to exchange sodium for potassium. Avoid taking these drugs while on sodium polystyrene sulfonate.
  • Digitalis: This heart drug affects the sodium and potassium levels in the heart, and taking sodium polystyrene sulfonate at the same time can cause dangerous imbalances in these levels.
  • Sorbitol: This is a laxative used to treat occasional constipation. Using sorbitol at the same time as sodium polystyrene sulfonate has been linked to cases of colonic necrosis (death of part of the colon).
  • Lithium: Taking sodium polystyrene sulfonate while on lithium may decrease how well lithium works.
  • Thyroxine: Taking sodium polystyrene sulfonate while on levothyroxine may decrease how well levothyroxine works.

What Medications Are Similar to SPS?

Some other drugs that work in the body by exchanging electrolytes to lower potassium levels include:

  • Veltassa (patiromer): Veltassa is a much newer drug for lowering potassium. It was approved in 2015 and is not available generically, so can be very expensive.
  • Lokelma (sodium zirconium cyclosilicate): Lokelma is an even newer drug that was approved to treat hyperkalemia in 2018. It has the ability to lower potassium very quickly, in as little as one hour. However, this drug is also very expensive given its newness and lack of generic availability.

This is not a list of drugs recommended to take with sodium polystyrene sulfonate. In fact, you should not take these drugs together. Ask your pharmacist or a healthcare provider before using any of these drugs with sodium polystyrene sulfonate.

Frequently Asked Questions

  • What is SPS used for?

    Sodium polystyrene sulfonate is used to lower potassium levels in the blood. Potassium is an electrolyte, and having too much of it in your blood can lead to abnormal and dangerous heart rhythms. Sodium polystyrene sulfonate is normally taken one to four times per day.

  • How does SPS work?

    Sodium polystyrene sulfonate works by absorbing potassium in exchange for releasing sodium as it moves through the intestine. The potassium level is then lowered as the drug is removed from the body in the stool.

  • What are the side effects of SPS?

    Sodium polystyrene sulfonate works in your digestive tract and does not get absorbed into your blood. Therefore, the most common side effects are gastrointestinal. These include loss of appetite, nausea, vomiting, and constipation. Sodium polystyrene sulfonate has the potential to lower your potassium levels too much, which can also lead to abnormal heart rhythms. Your potassium level should be monitored regularly while you take this medication.

How Can I Stay Healthy While Taking SPS?

When they think about electrolytes, many people probably think about drinks like Gatorade or Pedialyte, but there’s more to electrolytes than just replenishing them with these drinks. Electrolyte levels in the body can be complicated and aren’t necessarily something many people are familiar with. But they are essential for things like the functioning of our muscles (including the heart), blood clotting, and bone health.

When taking sodium polystyrene sulfonate, it is important to be aware of the signs and symptoms that indicate a change in your potassium or other electrolyte levels. Be sure to watch for;

  • Headaches
  • Dizziness
  • Confusion
  • Fatigue
  • Muscle weakness or cramps
  • Fast or irregular heartbeat

Speak with your healthcare provider if you have questions about how your electrolyte levels are being monitored.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. MedlinePlus. Sodium polystyrene sulfonate.

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  6. Palmer BF. Potassium binders for hyperkalemia in chronic kidney disease-diet, renin-angiotensin-aldosterone system inhibitor therapy, and hemodialysis. Mayo Clin Proc. 2020;95(2):339-354. doi:10.1016/j.mayocp.2019.05.019

  7. Bounthavong M, Butler J, Dolan CM, et al. Cost-effectiveness analysis of patiromer and spironolactone therapy in heart failure patients with hyperkalemia. Pharmacoeconomics. 2018;36(12):1463-1473. doi:10.1007/s40273-018-0709-3

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By Sara Hoffman, PharmD
Sara is a clinical pharmacist that believes everyone should understand their medications, and aims to achieve this through her writing.