Constipation: opioid antagonists in people prescribed opioids

Constipation is a common adverse effect of opioids. As an example, constipation is reported in 52% of people with advanced malignancy, and this figure rises to 87% in people who are terminally ill and taking opioids. There is no reason to believe that people with chronic non-malignant disease who are prescribed opioids will be any less troubled by this adverse effect.

We conducted a systematic overview and aimed to answer the following clinical question: What are the effects of opioid antagonists for constipation in people prescribed opioids? The population we studied included people with any condition, although most studies were in people with cancer pain. We searched Medline, Embase, The Cochrane Library, and other important databases up to May 2014 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review).

At this update, searching of electronic databases retrieved 162 studies. After deduplication and removal of conference abstracts, 84 records were screened for inclusion in the review. Appraisal of titles and abstracts led to the exclusion of 47 studies and the further review of 37 full publications. Of the 37 full articles evaluated, two systematic reviews and one RCT were included at this update. We performed a GRADE evaluation for three PICO combinations.

In this systematic overview we categorised the efficacy for three interventions based on information relating to the effectiveness of alvimopan, methylnaltrexone, and naloxone.