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The treatment - constipation

Honorary consultant paediatrician Professor David Tappin continues our new series of prescribing advice for GPs with his look at constipation

It is important to think of constipation as a chronic condition, like asthma, where there is no cure but very good treatment in the form of long-term stool softeners to manage the illness. Children with constipation have a large intestine that removes too much water and makes stools at times hard, difficult to pass and painful. Making sure children have soft painless stools to pass at all times will resolve the symptoms of constipation in most cases. However, if stool softeners are stopped – repeatedly leading to recurrent episodes of hard painful stools – the child may go on to develop long-term withholding, overflow incontinence and associated significant psychological trauma.

Standard current treatment

Once constipation has been diagnosed, the key to treatment is the use of a macrogol preparation in the doses described in the NICE guideline (see box).1 My own experience is that disimpaction regimes often lead to massive diarrhoea and loss of parental co-operation. I tend to increase gradually at two weekly intervals until soft stools are achieved, though this slower approach is sometimes not possible.

Macrogol preparations for treating constipation1

Paediatric formula: oral powder – macrogol 3350 (polyethylene glycol 3350) 6.563g; sodium bicarbonate 89.3mg; sodium chloride 175.4 mg; potassium chloride 25.1mg/sachet (unflavoured)

Disimpaction

  • Child under one year – ½-one sachet daily (non-BNFC recommended dose)
  • Child 1-5 years – two sachets on the first day, then four sachets daily for two days, then six sachets daily for two days, then eight sachets daily (non-BNFC recommended dose)
  • Child 5-12 years – four sachets on the first day, then increased in steps of two sachets daily to a maximum of 12 sachets daily (non-BNFC recommended schedule)

Ongoing maintenance (chronic constipation, prevention of faecal impaction)

  • Child under one year – ½-one sachet daily (non-BNFC recommended dose)
  • Child 1-6 years – one sachet daily; adjust dose to produce regular soft stools (maximum four sachets daily) (for children under two, non-BNFC recommended dose)
  • Child 6-12 years – two sachets daily; adjust dose to produce regular soft stools (maximum four sachets daily)

One third of children need to continue macrogols for up to two years, one third for up to five years and one third indefinitely. In the latter group, an attempt to reduce or stop the macrogol medication leads to rapid recurrence of hard painful stools. Of note is that one sachet of paediatric macrogol is equivalent to about 80mls of lactulose. It is important that each sachet of macrogol is given with 60 ml or two fluid ounces of a water-based liquid such as water or squash.

It is tempting to say to parents that if stools become loose – a type 6 or 7 on the Bristol Stool Chart – then reduce the macrogol, and if they become painful or hard then increase macrogol again. My experience is that this advice often leads parents to chasing the problem, as there is a lag between increasing or decreasing medication and seeing an effect in the stools. My own practice is to keep a close eye until a level of macrogol is reached that guarantees that every stool is soft, even if some are loose. Medication should only be changed, in my opinion, every two weeks. It is best to go up fairly slowly with two-weekly increases and to come down even more slowly in half-sachet increments to avoid inadvertently repeating the hard stool cycle.

What’s newly available

Macrogols for treating childhood constipation and extending this to infants, as advised by the NICE guidelines in 2010, is the big step forward.1 The use of macrogols as described in the BNF is limited to a licence greater than two years and a recommendation to use them for children greater than one year. Nurses are often only allowed to prescribe medications to their licensing limitations. My experience is that both GPs and paediatricians are wary of prescribing macrogols to children under one year of age. This is a shame as in this age group macrogols can be game changing.

What has fallen out of fashion and why

Fibogel and lactulose are used less. Children love to play about with fibogel – they soon learn to put off drinking the medication until it goes solid. Lactulose is sticky and often needs to be given in large volumes to effectively soften stools. Senokot and sodium picosulphate are used less frequently and usually only as an adjunct to stool softeners. They make the bowel work harder to try to overcome the child’s withholding habit. This often leads to pain and less control of when and where stools are passed.  

Enemas are only really used in secondary care, and they probably should be replaced by adequate macrogol medications in most cases. Glycerine suppositories can be used to limit some of the pain of passing hard stools before adequate doses of oral stool softeners reach the anus.

As with all medications, parents, surgeons, paediatricians and GPs want to stop them. My practice is clogged with young babies and children on one or two sachets of macrogol. They have soft stools and develop a normal toileting routine themselves, but I am loathe to discharge these patients. If I do, some parents and GPs tend to stop the macrogols. They think: ‘well the specialist has discharged him/her so the constipation must be cured’. It doesn’t seem to matter what is written in the discharge letter about continuing the medication. The children are referred back months or years later often withholding and with overflow incontinence which can be very difficult to manage.

Special cases

Treating babies in nappies with adequate doses of stool softeners over long periods is one of the most rewarding aspects of paediatric care. Distraught parents become happy, as do the babies and children being treated. The vital issue is to keep going until children are at least four years of age and have developed continence – if a child needs a sachet of macrogol to produce type 4 stool then so be it. If you stop the medication he/she will again develop hard painful stools and will repeat the hard stool cycle, moving down the slope towards long-term withholding, long-term incontinence and psychological trauma.

There is no evidence that long-term use of macrogol (or any other laxative medication) makes the bowel lazy.1 In fact, holding on makes the bowel sluggish and passing soft stool regularly makes the bowel work better. Even if babies have three loose stools a day you can reassure parents that their child will develop continence easily. However, if one hard stool appears when softeners are reduced, the child may again withhold and not pass stools on the potty or toilet.

Non-drug options and their evidence base

The evidence base for increasing fibre in the diet as a single treatment for constipation is poor.1 However, making sure children take plenty of water-based fluids is important. Getting worried parents on your side to deliver long-term stool softeners is not helped by inferring they are giving their babies or children a poor diet – this may not be how the dietary advice was meant but it is nearly always how parents will remember what you have said. Diet is medical dogma with little evidence, but a strong following among those not truly informed. In my practice it makes the treatment process more difficult because parents are very sensitive as they blame themselves anyway for their child’s constipation.

Professor David Tappin is a consultant paediatrician and professor of clinical trials for children at the University of Glasgow.

1 NICE: CG99: Constipation in children and young people. London: NICE; 2010

Bristol stool charts are available as one of the appendices to the full guidance document above.

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Readers' comments (5)

  • great article,
    thank you Professor for the reminder.
    Thank you Pulse for publishing this.

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  • Sensible advice by a down to earth doctor.Many thanks

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  • great article and highlights that we should be using macrogols. Why do so many GPs continue to prescribe lactulose then???

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  • thanks alot

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  • Tremendously useful, thank you, and will certainly encourage me to be more assertive about advising parents to give adequate macrogol and not to be trigger-happy about stopping it.

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