Sodium Phosphate Dibasic and Sodium Phosphate Monobasic (Rectal)

The combination of sodium phosphate dibasic and sodium phosphate monobasic is a laxative that is used for the treatment of occasional constipation.


Sodium phosphate dibasic and sodium phosphate monobasic is a combination drug used in the treatment of occasional constipation.

The medication can be used in both children and adults and is available as an enema. This medication is available without prescription from a pharmacy.

Condition treated

  • Constipation

Type of medicine

  • Laxative

Side Effects

Along with the desired laxative effects when using this treatment, it is possible that unwanted side effects may occur. In some cases, these side effects may need to be treated, but in other cases, they may not necessitate medical attention.

You should check with your doctor as soon as possible if you experience any of the following side effects:

  • Bleeding inside the rectum
  • Confusion or disorientation
  • Decrease in volume or frequency of urination
  • Dry mouth or feeling of dehydration
  • Feeling of dizziness
  • Feeling of faintness or fainting
  • Increase in heart rate
  • Lightheadedness
  • Rapid or shallow breathing
  • Sunken eyes or appearance of extreme tiredness
  • Thirstiness
  • Unusual tiredness
  • Unusual weakness
  • Wrinkling of the skin

Other side effects may occur that have not been listed above. If you experience any other side effects, you should contact your doctor to seek advice.


If this medication is prescribed to you then you should use it only as instructed by your doctor. You should not exceed the dose recommended and should not use it more frequently than recommended.

Before use, you should inform your doctor if you or your child follows a sodium reduced dietary plan.

If you are using this medication without a prescription, you should follow the guidance on the packaging and medicine label. Do not exceed the dose as detailed and do not use more frequently than recommended.

To use this medication you should follow these steps:

  • Never take this medication orally. This medication is for rectal use only and should not be swallowed.
  • Wash the hands thoroughly before using this medication.
  • Ensure that the rectum and surrounding area is thoroughly clean before using this medication.
  • Rest on your left-hand side with the left leg straightened. Bend your right knee upwards. (Reverse if you are left-handed)
  • Insert the applicator end into the rectum and push in until roughly an inch of the tube is inserted.
  • Gently squeeze the bottom section of the bottle in order to insert the enema into the rectal cavity.
  • Remove the applicator and dispose of it hygienically.
  • Retain the liquid in your rectum for as long as you can. The medication can take tens of minutes to hours to work effectively. This can be difficult at first but will become easier over time as you get used to using this treatment.
  • If a child has been prescribed a half-dose then you should remove 2 measured tablespoons of the treatment from the bottle before following the process above.
  • Never use more than a single bottle within a 24 hour period.
  • Never use the enema is the bottle's seal is missing or broken when you unpackage it.

The dose of this treatment will differ for each patient. You should follow the instructions of your doctor if prescribed and follow the directions on the medication guide if you are using this treatment without a prescription. The following dosage information is a guideline only and you should not change your dose unless otherwise instructed by a healthcare professional.

For relief from constipation:

Adults and children aged 12 years or older.

  • One bottle of Fleet ® saline treatment.

Children aged 5-11.

  • One bottle of pedia-laxâ„¢ treatment.

Children aged 2-5.

  • Half a bottle of pedia-laxâ„¢ treatment.

Children under the age of 2.

  • Use and dosage to be determined by the doctor.

Do not exceed doses of this medication. Doing so can put you at increased risk of serious side effects.

Do not use in conjunction with any other sodium phosphate laxatives.


Certain medications can interact with one another and cause severe side effects in a patient. Some medications should never be used together, while others may require dosage adjustments to be used in conjunction with one another. Before taking this medication you should inform your doctor of all other medications that you are taking. This includes other laxatives, over the counter medications, prescription medications, and herbal remedies.

This medication should not be used in conjunction with other sodium phosphate medications without first consulting your doctor.

Medications can also interact with other medical conditions that you have. You should tell your doctor about any other medical conditions from which you suffer or from which you have suffered in the past before taking this medication. This is especially important if you suffer from any of the following conditions. Use when suffering from any of the following can make these medical conditions worse:

  • Dehydration
  • Kidney disease
  • Ongoing abdominal pains
  • Recent ongoing vomiting or nausea
  • Stomach or bowel problems


Before using this medication you should consider the risks of use in relations to the benefits of use. You and your doctor, having considered all factors that may impact use, should make this decision together. This includes health conditions that you suffer from, conditions that you have suffered from in the past, allergies, age and general health.

You should inform your doctor if you have used another laxative for more than one week before using this treatment.

You should contact your doctor immediately if you notice any rectal bleeding from yourself or your child after treatment.

If your child has not had a rectal movement after 30 minutes of use then you should contact your doctor.

Dehydration is a risk when using this medication. Ensure that you or your child is drinking plenty whilst receiving this treatment. The following symptoms of dehydration can be signs of a serious problem:

  • Confusion or disorientation
  • Decreased volume of urination
  • Feeling of thirstiness
  • Dry mouth
  • Vomiting

Do not take this medication in conjunction with any other medication that contains sodium phosphate.

Risks of use during pregnancy cannot be ruled out. If you are pregnant you should discuss use with your doctor before using the treatment. Alternative medications that pose a lower risk to a developing fetus are available for use. Use on a pregnant woman would only be recommended where there is a clear need to do so.


This medication should be stored at room temperature and in the original packaging. Prevent the medication from freezing or being exposed to heat, moisture, and direct light.

All medications should be kept out of reach of small children at all times.

Dispose of unwanted medication or outdated medication as soon as possible. Dispose of used bottles and applicators as soon as possible after use. Ensure disposal is hygienic and keep out of reach of children.

It is possible to overdose on this medication. If you suspect that you or someone else has overdosed or are experiencing the symptoms of overdose then you should seek emergency medical attention. The symptoms of overdose are as follows:

  • Abdominal pain
  • Blurry vision
  • Change in heart rate
  • Chest pain
  • Decrease in feelings of hunger
  • Decreased frequency of urine
  • Discomfort in the upper chest region
  • Dizziness or feeling of faintness or lightheadedness when rising from lying or sitting down suddenly.
  • Dry mouth or feeling of dehydration
  • Increase in weight
  • Increased thirstiness
  • Lightheadedness
  • Lower back
  • Muscle cramping experienced in the hands, arms, legs, feet or face
  • Muscle pain
  • Pounding or rapid pulse
  • Rapid breathing
  • Restlessness
  • Side pain
  • Stomach cramps
  • Sunken eyes or appearance of extreme tiredness
  • Sweating when warm
  • Tremor or shaking
  • Unusual weakness
  • Wrinkling of the skin


Sodium phosphate dibasic and sodium phosphate monobasic is a combination of medications that can be used to relieve occasional constipation. It can be used with or without a prescription from your doctor and is available from pharmacies.

The treatment is self-administered with an applicator as an enema that is inserted into the rectum. The dosage used is usually one bottle for adults and one-half bottle for children, although this depends on brand and strength of medication.

This medication should not be used in conjunction with any other medications that contain sodium phosphate as there is a risk of overdosing.

When taking this medication you should ensure that you drink plenty of water before, during and after use to avoid becoming dehydrated.

This medication can make some medical conditions worse.

If you are using this treatment without a prescription then you must ensure that you read the medical guidance sheet thoroughly before use and adhere to the instructions to avoid putting yourself at risk.

Ensure that your hands and rectum are clean before use. Prevent the applicator from touching any surfaces before use and dispose of it hygienically once you have used the treatment.

Last Reviewed:
December 24, 2017
Last Updated:
April 05, 2018
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