Slow sodium (Sodium chloride)

How does it work?

Slow sodium tablets contain the active ingredient sodium chloride, which is a salt that is normally found dissolved in the body fluids.

Sodium chloride is important in regulating the pressure and flow of fluids between the blood and tissues of the body. It is also important for normal nerve and muscle function.

Low sodium levels in the body can result in muscle cramps, dehydration and low blood pressure. In some long-term conditions, for example ulcerative colitis or kidney disease, excessive sodium chloride is lost from the body. Haemodialysis for kidney failure removes sodium from the blood and can cause muscle cramps during the treatment. Sodium chloride is also lost from the body in urine and sweat.

Sodium chloride tablets are used to replace sodium lost from the body and thereby return sodium chloride levels to normal. This helps reverse the symptoms of sodium depletion.

What is it used for?

  • Preventing and correcting low levels of sodium in the body.

How do I take it?

  • Slow sodium tablets should be swallowed whole with water (at least 70ml of water per tablet in people with normal kidney function). The tablets should not be chewed or broken.
  • The number of tablets that you need to take each day will depend on your blood level of sodium; this will be assessed by a blood test. It is important to follow the instructions given by your doctor and the directions printed on the dispensing label.


  • Your doctor may want you to have regular blood tests to check your sodium level and levels of other salts while you are taking this medicine.
  • It is important to drink plenty of water while you are taking this medicine. This prevents the level of sodium in your blood from rising too high. Follow the advice given by your doctor.
  • The skeleton matrix of this tablet, from which the medicine is released, passes through the gut and may be visible in the stools. This is normal and not harmful.

Not to be used in

  • Any intestinal disease in which obstruction or narrowing of the gut (stricture) or sacs in the wall of the gut (diverticula) may occur, for example Crohn's disease.
  • Any condition where salt retention may be undesirable, for example the conditions listed below:
  • People with swelling caused by excess fluid retention (oedema).
  • Heart disease.
  • Heart failure.
  • People with overproduction of aldosterone, a steroid hormone that regulates salt and water balance in the body (hyperaldosteronism).
  • People receiving therapy to decrease sodium and/or water levels in the body, eg people taking diuretics.

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine is not known to be harmful if used to correct low blood sodium levels during pregnancy or breastfeeding, provided the mother's sodium level does not rise too high. However, as with all medicines it should be used with caution during pregnancy and breastfeeding, and only if the expected benefit to the mother is greater than any possible risk to the baby. Seek further medical advice from your doctor.

Label warnings

  • This medication is to be swallowed whole, not chewed.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • No side effects have been reported with this medicine when used at the recommended doses. If doses are too high, or insufficient amounts of water are drunk, this could result in the level of sodium in the blood rising too high (hypernatraemia).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.

Sodium chloride is not known to affect other medicines. However, in people with chronic kidney failure and high blood pressure, sodium chloride tablets may make blood pressure lowering medicines less effective.

Other medicines containing the same active ingredient

Sodium chloride infusion