Subcutaneous Neostigmine for the Management of Acute Colonic Pseudoobstruction: A Scoping Review

Acute colonic pseudoobstruction (ACPO) carries significant morbidity and mortality if left untreated, with associated complications of toxic megacolon, bowel ischaemia and perforation. Current management involves optimisation of electrolytes, judicious fluid management and regular aperients. In progressive cases, aggressive intervention with intravenous neostigmine or colonoscopic decompression is considered. Intravenous neostigmine is an effective treatment for pseudoobstruction, however carries risks of anti-cholinergic side-effects and cardiac toxicity. Emerging evidence suggests subcutaneous neostigmine may offer similar efficacy albeit favourable safety profile, but this effect remains poorly characterised. This scoping review explores the current literature surrounding the use of subcutaneous neostigmine in ACPO. A scoping review was performed following a comprehensive search of Medline, Embase and Cochrane Central databases. Articles evaluating outcomes associated with subcutaneous formulations of neostigmine for the management of ACPO were included. Subcutaneous formulation of neostigmine appears to be a safe and effective treatment for ACPO with timely resolution of symptoms. The need for colonoscopic decompression due to failed treatment and incidence of anti-cholinergic side-effects is low. These findings are based on retrospective studies with small sample sizes with significant clinical heterogeneity and poor control of confounders. Despite emerging evidence suggesting subcutaneous neostigmine is an efficacious and safe treatment for ACPO, there are important limitations to the quality of the evidence. Our scoping review highlights the need for larger prospective trials to robustly assess treatment effect before subcutaneous neostigmine can be considered in evidence-based ACPO guidelines.