Phosphate supplements for low phosphate levels

This leaflet is about the use of phosphate supplements for the treatment of hypophosphataemia (low levels of phosphate in the blood).

Information Standard quality markThis leaflet has been written specifically for parents and carers about the use of this medicine in children. The information may differ from that provided by the manufacturer. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again. 

Name of drug

Phosphate supplements (may also be called sodium phosphate, or neutral sodium phosphate)

Brand name: Phosphate-Sandoz®

Why is it important for my child to take this medicine?

The body needs phosphate to work properly, especially for healthy bones and teeth. Your child may have low phosphate levels because of either taking too little phosphate in their diet (e.g. in premature babies) or losing too much phosphate (e.g. from the kidneys). Phosphate supplements help to increase the levels of phosphate in the blood.

What are phosphate supplements available as? 

  • Effervescent (fizzy) tablets: each tablet contains 16.1 mmol phosphate, 20.4 mmol sodium and 3.1 mmol potassium 
  • Liquid medicine can be ordered specially from your pharmacist 

When should I give phosphate?

Your child needs to have the right dose of phosphate each day, which may be in two, three or four divided doses. Your doctor will tell you how often to give it.

  • Twice a day: this should be once in the morning and once in the evening. Ideally, these times are 10–12 hours apart, for example some time between 7 and 8 am, and between 7 and 8 pm.
  • Three times each day: this should be once in the morning, once in the early afternoon and once in the evening. Ideally, these times are at least 6 hours apart, for example 8 am, 2 pm and 8 pm.
  • Four times a day: this is usually first thing in the morning, at about midday, late in the afternoon and at bedtime. Ideally, these times should be at least 4 hours apart, for example 8 am, midday, 4 pm and 8 pm.

Give the medicine at about the same times each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of phosphate (the dose) that is right for your child. The dose will be shown on the medicine label. 

The doctor will measure the level of phosphate in your child’s blood and adjust the dose of phosphate to get the levels in the blood right – they may change the dose with each visit. Your doctor or pharmacist will discuss this with you. 

It is important that you follow your doctor’s instructions about how much to give.

How should I give it?

Effervescent tabletsEffervescent tablets: Dissolve the tablet in a glass of water. You can add juice or squash to hide the taste. Your child should then drink it all either straight away or over a period of about 30 minutes. Your child should not chew these tablets. 

You can crush the tablet and mix it with a small amount of soft food such as, honey or jam. Make sure your child swallows it straight away, without chewing. Do not give the medicine with milk or yoghurt.

Liquid medicineLiquid medicine: Measure out the right amount using an oral syringe or medicine spoon. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

When should the medicine start working?

The medicine will start to work within a day or two, although you may not see any difference in your child.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of sodium phosphate, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of sodium phosphate, you do not need to give them another dose. Wait until the next normal dose.

What if I forget to give it?

Give the missed dose as soon as you remember. Try to give all the doses in one day, without doubling up. Make sure you leave at least two hours between doses.

What if I give too much?

You are unlikely to cause harm if you give your child an extra dose of phosphate by mistake. If you think you may have given them too much, contact your doctor or NHS Direct (0845 4647 iin England and Wales; 08454 24 24 24 in Scotland) for advice. Have the medicine or packaging with you if you telephone for advice.

Are there any possible side-effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side-effects). 

  • Your child may have diarrhoea, stomach or abdominal cramps and may feel sick (nausea) or be sick (vomit) when they first start taking phosphate or if they have larger doses. Giving each dose with or after food may help. If it is still a problem after a week, contact your child’s doctor. 

Can other medicines be given at the same time as phosphate?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • You should avoid giving your child any medicines that contain calcium, magnesium or aluminium (e.g. indigestion remedies / antacids) at the same time as giving phosphate. Wait at least two hours after giving a phosphate dose.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes vitamins, herbal and complementary medicines.

Is there anything else I need to know about phosphate?

When you get a new bottle of liquid medicine, check what strength you have been given and how much to give your child, as this may be different from the previous supply. If you are not sure how much to give, contact your doctor or pharmacist.

  • Liquid medicine may not keep for long once the bottle has been opened. Do not use the medicine past the expiry date.

General advice about medicines

  • Try to give the medicine at about the same times each day, to help you remember.
  • If you are not sure a medicine is working, contact your doctor but continue to give the medicine as usual in the meantime. Do not give extra doses, as you may do harm.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm. 
  • If you think someone else may have taken the medicine by accident, contact your doctor for advice.
  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • Make sure that the medicine you have at home has not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where I should keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight. 
  • Once opened the liquid medicine should be kept in the fridge
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information

Your child’s doctor, pharmacist or nurse will be able to give you more information about sodium phosphate and about other medicines used to treat low phosphate levels (hypophosphataemia).


You can also get useful information from:


Publication Date

7/12/2011

Copyright Disclaimer

Version 1.2, September 2011 (November 2011). © NPPG, RCPCH and WellChild 2011, all rights reserved. Reviewed by: September 2013.

The primary source for the information in this leaflet is the British National Formulary for Children. For details on any other sources used for this leaflet, please contact us through our website, www.medicinesforchildren.org.uk.

We take great care to make sure that the information in this leaflet is correct and up-to-date. However, medicines can be used in different ways for different patients. It is important that you ask the advice of your doctor or pharmacist if you are not sure about something. This leaflet is about the use of these medicines in the UK, and may not apply to other countries. The Royal College of Paediatrics and Child Health (RCPCH), the Neonatal and Paediatric Pharmacists Group (NPPG), WellChild and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this leaflet.