Search strategy and data collection
All studies reporting on pharmacological intervention for POI treatment and prevention were considered eligible for analysis. The literature was systematically reviewed by searching in the PubMed, EMBASE and Cochrane Libraries with no restrictions concerning the publication period. The search period ended on 1st July 2022. The medical subject headings (MESH) used are summarised in Supplemental Table 1. The full search strategies are listed in Supplement Table 1. They are adapted from previous systematic reviews including ones from our team’s work5 and used with bibliographic databases in combination with database-specific filters for controlled trials where available. Trials investigating pharmacological treatments for post-operative ileus after abdominal surgery were searched by adding boundaries for randomised controlled trials (with the exploded terms ”random” ”trial” or ”RCT”).