Laxatives for the management of constipation in people receiving palliative care

Background

People with an incurable illness may receive palliative care, which involves making the person as comfortable as possible by controlling pain and other distressing symptoms. People receiving palliative care commonly experience constipation. This is as a result of the use of medicines (e.g. morphine) for pain control, as well as disease, dietary and mobility factors. There is a wide range of laxatives available. The aim of this review was to determine what we know about the effectiveness of laxatives for the management of constipation in people receiving palliative care.

Study characteristics

We searched medical databases for clinical trials of the use of laxatives for constipation in people receiving palliative care. Two review authors assessed study quality and extracted data.

Key results and quality of evidence

We identified five studies involving 370 people. The laxatives evaluated were lactulose, senna, co-danthramer combined with poloxamer, docusate and magnesium hydroxide combined with liquid paraffin. Misrakasneham was also evaluated; this is a traditional Indian medicine and is used as a laxative, containing castor oil, ghee, milk and 21 types of herbs.

There was no evidence on which laxative provided the best treatment. However, the review was limited as the evidence was from only five small trials and patient preference and cost were under evaluated. Further rigorous, independent trials are needed to evaluate the effectiveness of laxatives.

Authors' conclusions: 

This second update found that laxatives were of similar effectiveness but the evidence remains limited due to insufficient data from a few small RCTs. None of the studies evaluated polyethylene glycol or any intervention given rectally. There is a need for more trials to evaluate the effectiveness of laxatives in palliative care populations. Extrapolating findings on the effectiveness of laxatives evaluated in other populations should proceed with caution. This is because of the differences inherent in people receiving palliative care that may impact, in a likely negative way, on the effect of a laxative.

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Background: 

This article describes the second update of a Cochrane review on the effectiveness of laxatives for the management of constipation in people receiving palliative care. Previous versions were published in 2006 and 2010 where we also evaluated trials of methylnaltrexone; these trials have been removed as they are included in another review in press. In these earlier versions, we drew no conclusions on individual effectiveness of different laxatives because of the limited number of evaluations. This is despite constipation being common in palliative care, generating considerable suffering due to the unpleasant physical symptoms and the availability of a wide range of laxatives with known differences in effect in other populations.

Objectives: 

To determine the effectiveness and differential efficacy of laxatives used to manage constipation in people receiving palliative care.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library), MEDLINE, EMBASE, CINAHL and Web of Science (SCI & CPCI-S) for trials to September 2014.

Selection criteria: 

Randomised controlled trials (RCTs) evaluating laxatives for constipation in people receiving palliative care.

Data collection and analysis: 

Two authors assessed trial quality and extracted data. The appropriateness of combining data from the studies depended upon clinical and outcome measure homogeneity.

Main results: 

We identified five studies involving the laxatives lactulose, senna, co-danthramer, misrakasneham, docusate and magnesium hydroxide with liquid paraffin. Overall, the study findings were at an unclear risk of bias. As all five studies compared different laxatives or combinations of laxatives, it was not possible to perform a meta-analysis. There was no evidence on whether individual laxatives were more effective than others or caused fewer adverse effects.

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