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This application is a service of the Singapore Government.

Health Sciences Authority

Use of Oral Sodium Phosphates


Responsible Use of Oral Sodium Phosphates

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There have been recent overseas reports of consumers suffering from kidney damage after using oral sodium phosphates (OSP) for bowel cleansing (purging). In light of this, regulatory agencies such as the United States Food and Drug Administration (FDA) and Health Canada have highlighted concerns on the risks associated with OSP products when used in high doses for bowel cleansing purposes.

To date, the Health Sciences Authority (HSA) has not received any adverse reports of kidney damage associated with OSP use in Singapore.

However, in view of this rare but serious safety concern linked to the use of OSP products, the HSA would like to recommend that consumers seek advice from a doctor or pharmacist before using these products for bowel cleansing.

What are Oral Sodium Phosphates (OSP) Commonly Used for?

OSP products are indicated for relief of occasional constipation or for preparing the bowel for medical procedures/examination. They are available over-the-counter as GSL (General Sales List) products. Examples of OSP that are available in Singapore are Fleet Phospho-Soda® Buffered Saline Laxative and Fleet Phospho-Soda® Oral Saline Laxative Ginger-Lemon.

Relief of constipation OSP products have been available for many years for use as laxatives for the relief of occasional constipation. When used at the appropriate doses for laxative purposes, these products generally do not pose any significant safety concerns or risk of acute kidney injury.

Bowel cleansing before medical procedures OSP products may also be used in healthcare settings for patients preparing to undergo medical examination such as colonoscopy, which is an examination of the large bowels. For this, a clean bowel is essential. Patients are usually prescribed OSP one day before the procedure, accompanied by comprehensive instructions/schedule on meals and fluid intake. The purgative dose of OSP required for bowel cleansing before a medical procedure is much higher than that used to treat constipation.

What are the Risks Associated With the Use of OSP Products?

When taken at purgative doses, OSP products can potentially cause serious side effects such as:

  • acute phosphate nephropathy, a form of acute kidney injury which can lead to permanent kidney function impairment;
  • electrolyte imbalance which can lead to symptoms such as twitching muscles, numbness, fatigue, irregular heartbeat and blood pressure changes.

Given that high doses of OSP can possibly lead to health problems if not used under medical supervision, it is therefore very important that patients are assessed by healthcare practitioners whether they are suitable to take OSP products for bowel cleansing before medical procedures. In addition, patients should be given proper, detailed instructions to drink enough fluids when taking OSP.

Who are at Risk?

Consumers who are most susceptible to acute phosphate nephropathy include:

  • older individuals, especially those over 55 years of age
  • individuals with a decreased circulating blood volume due to health conditions such as dehydration, congestive heart failure and liver impairment
  • individuals with kidney impairment, bowel obstruction, or active colitis (inflammation of the colon)
  • individuals concurrently taking medications such as diuretics used to remove excessive body fluids, certain blood pressure medications and painkillers that may affect kidney function

How can Consumers Protect Themselves from Risks Linked to OSP Products?

HSA has three tips for consumers:

Tip 1:
To use OSP products for bowel cleansing only if these are prescribed by their doctors.

Tip 2:
To always seek advice from a healthcare professional to determine if OSP products are suitable and/or required for their specific needs.

Tip 3:
To closely follow the instructions given by a healthcare professional when using OSP products for bowel cleansing.