Pharmacy Services

Sodium Phosphate OTC Products

January 10, 2014

FDA issued a MedWatch warning that sodium phosphate over-the-counter (OTC) products can alter serum electrolytes, cause dehydration, damage heart and kidneys, and cause death, when used at higher-than-recommended doses or when more than one dose is used in 24 hours.

Sodium phosphate OTC products are used to treat constipation. These products are available as Fleet brand, store brands, and generic products. Sodium phosphate products are available as oral or rectal solutions with either a single ingredient or a combination of sodium phosphate and sodium biphosphate ingredients. Adverse events have occurred with both the oral and rectal products.

Young children and patients older than 55 years of age are at increased risk of adverse events with higher-than-recommended doses of these products. Other risk factors include dehydration, hypovolemia, kidney disease, bowel obstruction, bowel inflammation, decreased intravascular volume, decreased bowel transit time, active colitis, and use of medications that affect kidney function including diuretics, angiotensin converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and nonsteroidal anti-inflammatory drugs (NSAIDs).

Recommendations for use of sodium phosphate OTC products:

  • Always read and follow labeled directions.
  • Do not exceed the recommended dose.
  • Do not use more than one dose in 24 hours, and do not use for more than 3 days.
  • Use oral products with caution in patients 5 years of age or younger, and only after consultation with a healthcare professional.
  • Never use rectal forms of this product in patients younger than 2 years of age.
  • Avoid concurrent use of other sodium phosphate laxatives.
  • Ensure adequate hydration during use.
  • For high risk patients, monitor serum electrolytes and renal function.
  • Report adverse events or side effects to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program.

Additional information is available at the following links:

January 10, 2014; University of Utah, Drug Information Service. Copyright 2014, Drug Information Service, University of Utah, Salt Lake City, UT.