Pharmacological treatment of opioid-induced constipation: moving ahead to new targets

We read with great interest the systematic review and network meta-analysis on pharmacological treatments for opioid-induced constipation (OIC).1 Based on 27 randomised controlled trials (RCTs, 9149 patients), the authors concluded that peripherally acting mu-opioid receptor antagonists (PAMORAs) and the prokinetic prucalopride were all more effective than placebo for OIC and that naloxone and naldemedine were the most efficacious ones.1 We have previously documented that OIC has high prevalence and is associated with reduced quality of life (QoL) in opioid-addicted patients treated with opioid substitution treatment (OST).2 Overweight is also common and interventions for weight loss are recommended in patients under OST.3 Orlistat, a weight-control drug that inhibits lipase, thereby decreasing fat absorption from the intestinal lumen, has been reported to improve drug-resistant constipation in small case series,4 5 and clozapine-induced constipation in a small RCT.6 In an open-label observational study, we explored whether orlistat may improve OIC in OST patients. From a cohort of 1057 heroin-dependent patients under OST previously reported,2 we recruited patients with OIC, who were prescribed orlistat 60 mg three times a day for weight reduction. OIC was measured with …