There has been no definitive synthesis of the evidence for any benefit of available pharmacological therapies in opioid-induced constipation.
Dr Alexander Ford and colleagues from the United Kingdom conducted a systematic review and meta-analysis to address this deficit.
The team searched MEDLINE, EMBASE, EMBASE Classic, and the Cochrane central register of controlled trials through to 2012 to identify placebo-controlled trials of μ-opioid receptor antagonists, prucalopride, lubiprostone, and linaclotide in the treatment of adults with opioid-induced constipation.
No minimum duration of therapy was required.
Trials had to report a dichotomous assessment of overall response to therapy, and data were pooled using a random effects model.
The research team identified 14 eligible randomized controlled trials of μ-opioid receptor antagonists, containing 4,101 patients.
These were superior to placebo for the treatment of opioid-induced constipation.
The researchers noted that methylnaltrexone, naloxone, and alvimopan were all superior to placebo.
The team found that total numbers of adverse events, diarrhea, and abdominal pain were significantly commoner when data from all RCTs were pooled.
Reversal of analgesia did not occur more frequently with active therapy.
Only one trial of prucalopride was identified, with a nonsignificant trend toward higher responder rates with active therapy.
The research team found that 2 randomized controlled trials of lubiprostone, with significantly higher responder rates with lubiprostone in both, but reporting of data precluded meta-analysis.
Dr Ford's team commented, "μ-Opioid receptor antagonists are safe and effective for the treatment of opioid-induced constipation."
"More data are required before the role of prucalopride or lubiprostone in the treatment of opioid-induced constipation are clear."