Constipation Medication - How to adjust Doses

The following page gives further information on constipation medication specifically related to how long it should continue for and how to make adjustments in the dose (with a diary you can download to help keep track of changes).

To read about the actual medications and their dosing schedules, click here.


What are laxatives?

Laxatives help the body to get rid of stool (poop, poo). There are two main ways in which constipation medication (laxative) works:

  • some soften the hard stool (softeners)
  • some help the bowel push the stool out (stimulants or emptiers)

Remember the aim of constipation treatment is for your child to have one soft but formed bowel motion per day. The Bristol Stool Chart shows how this should look - to view, click here.

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How long are laxatives (constipation medication) necessary?

For as long as it takes. Children sometimes need laxatives for months rather than weeks. Remember that the purpose of constipation medication (laxatives) is to allow the bowel to develop a normal habit.

Ideally, we are aiming for 1 soft but formed bowel motion per day.

So laxatives are required until the body can manage one soft but formed bowel motion per day without help. You will need to adjust the dose of the laxative as things progress and your child's gut gets used to passing a normal stool by itself.

Used in the correct dosage, laxatives are generally safe in children.

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How can I adjust the dose of the laxative?

Say, your child is prescribed 10ml of Lactulose twice a day as constipation medication. If she is 3 years old (and so about 14 kg in weight), she could have a maximum dose of 15 ml twice a day.

If her stools are still hard after a few days to a week, increase the dose. Start by giving 12.5 ml in the morning and 10 ml at night.

If that isn't enough and the stools are still hard after a few days, increase the dose to 12.5 ml twice a day.

And if necessary, you can make a further step to 15 ml in the morning and 12.5 ml at night before needing to go to the full 15 ml twice a day dose.

So the steps up can be:

  • 10 ml morning, 10 ml evening
  • 12.5 ml morning, 10 ml evening
  • 12.5 ml morning, 12.5 ml evening
  • 15 ml morning, 12.5 ml evening
  • 15 ml morning, 15 ml evening

Remember leave at least 3 days to a week between each step of changing the constipation medication (laxative).

Once your child is going to the toilet daily with a soft but formed bowel motion, slowly reduce the dose in small steps - so from 15 ml twice a day to 15 ml in the morning and 12.5 ml at night, and then 12.5 ml twice a day and so on.

Only make a new change after you have waited for a few days to see the effect of the last change. There is no point trying to rush - go at the pace your child's body sets.

Eventually, you may only need to be giving laxatives on days when your child misses going to the toilet or if your child has a hard bowel motion.

So the steps down can be:

  • 10 ml morning, 10 ml evening
  • 10 ml morning, 7.5 ml evening
  • 7.5 ml morning, 7.5 ml evening
  • 7.5 ml morning, 5 ml evening
  • 5 ml morning, 5 ml evening
  • 5 ml morning,
  • 5 ml morning alternate days
  • 5 ml morning occasionally if a hard bowel motion (stool, poop, poo)

Remember leave at least 3 days to a week between each step. For infants, the dose may go down to 2.5 ml per dose at the lowest instead of 5 ml.

It is often helpful to keep a diary. Below is an example of a diary to keep track of constipation medication changes and monitor progress. You can download to an Excel table by right-clicking on it.

Bowels open

Morning Medication (mls)
Evening medication (ml)

Remember, the aim is for your child to have one soft but formed bowel motion per day.

Sometimes large doses of laxatives are required (higher than the doses stated on this site), but these should only be given under medical supervision.

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What else can I do to help?

As well as constipation medication, it is important for your child to develop a good toileting habit.

  • Get her to sit on the toilet for 15 minutes after meals
  • Make sure she is comfortable - for example, put a stool under her feet
  • Make it a fun time - read a book
  • Don't worry if she doesn't pass a stool (poop, poo) - the important thing is to develop the habit. Eventually, she will pass stool on the toilet.

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  • Susan S. Baker, Gregory S. Liptak, Richard B. Colletti, Joseph M. Croffie, Carlo DiLorenzo, Walton Ector, and Samuel Nurko. CONSTIPATION IN INFANTS AND CHILDREN: EVALUATION AND TREATMENT. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition

To go to the top of the Constipation Medication page, click here

To read about Actual Doses of Constipation Medications, click here

To view what normal poop/poo looks should look like, click here

To go to the main Constipation page, click here

To return to the Home page, click here

Last reviewed 3 June 2010

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Dr Maud MD

Dr Maud MD (MBChB, FRACP, FRCPCH), a specialist pediatrician, provides health information and medical advice for parents of babies and toddlers. Read more about Dr Maud.

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