As discussed in the MeReC Bulletin on managing constipation, most cases of mild or acute functional (idiopathic) constipation in adults can be managed by dietary and lifestyle changes. In adults, laxatives should be reserved for constipation that has not responded adequately to simple interventions, or for when rapid relief of symptoms is needed.
The evidence for the safety and efficacy of all laxatives is limited. This is mainly because many laxatives have been in use for a long time and were licensed when clinical trials were less robust. Few comparative clinical trials have been carried out, although a Cochrane review (CD007570) of studies in adults and children concluded that polyethylene glycol was superior to lactulose for outcomes such as stool frequency per week, form of stool, relief of abdominal pain and the need for additional laxatives. Another Cochrane review (CD009118) also found evidence that polyethylene glycol preparations may be superior to placebo, lactulose and milk of magnesia (magnesium hydroxide) for childhood constipation.
Prescribing choice mainly depends on the presenting symptoms, the person's preference and cost. Prolonged treatment is seldom necessary, except occasionally in the elderly, in palliative care or to prevent constipation recurring in children.
When managing constipation in children and young people, healthcare professionals should follow the NICE guideline on constipation in children and young people. This advises that dietary interventions should not be used alone as first-line treatment for constipation (as they would be for adults). The guideline recommends polyethylene glycol as first-line laxative treatment for disimpaction and maintenance treatment.
The NICE guideline on the use of strong opioids in palliative care in adults advises that laxatives should be prescribed for everyone starting strong opioids. It recommends that laxatives should be taken regularly at an effective dose and that people should be informed of the importance of medicines adherence.
The NICE guideline on irritable bowel syndrome (IBS) recommends that laxatives should be considered for treating constipation in people with IBS, but that people should be discouraged from taking lactulose.
The NICE technology appraisal guidance on prucalopride recommends this as a possible treatment for chronic constipation only in women for whom treatment with at least 2 laxatives from different classes, taken at the highest tolerated recommended doses for at least 6 months, has failed to provide adequate relief and invasive treatment for constipation is being considered.
The NICE technology appraisal guidance on lubiprostone recommends this as a possible treatment for chronic idiopathic constipation in adults for whom treatment with at least 2 laxatives from different classes, taken at the highest tolerated recommended doses for at least 6 months, has failed to provide adequate relief and invasive treatment for constipation is being considered.
See the NICE Clinical Knowledge Summaries on constipation, constipation in children and palliative cancer care – constipation for general overviews of the condition. The NICE pathway on constipation brings together all related NICE guidance and associated products in a set of interactive topic-based diagrams. There is also a NICE quality standard defining clinical best practice for constipation in children and young people.