PyRICo-Pilot: pyridostigmine to reduce the duration of postoperative ileus after colorectal surgery - a phase II study.

AIM

Postoperative ileus (POI) is a major problem after colorectal surgery. Acetylcholinesterase inhibitors such as pyridostigmine increase gastrointestinal (GI) motility through a cholinergic anti-inflammatory pathway. The purpose of this phase II pilot study is to determine the safety of oral pyridostigmine after elective colorectal surgery.

METHOD

This is a Stage 2b safety study (IDEAL framework). All adult patients undergoing elective colorectal resection or formation or reversal of stoma at the Royal Adelaide Hospital between September 2020 and January 2021 were eligible. The primary outcomes were 30-day postoperative complications, reported adverse events and GI-2 - a validated composite outcome measure of recovery of GI function after surgery, defined as the interval from surgery until first passage of stool and tolerance of a solid intake for 24 h (in whole days) in the absence of vomiting.

RESULTS

Fifteen patients were included in the study. The median age was 58 (range 50-82) years and seven (47%) were men. Most participants had an American Society of Anesthesiologists grade ≥2 (53%) and the median body mass index was 27 (24-35) kg/m . There were 13 postoperative complications [seven were Clavien-Dindo (CD) 1, five CD 2 and one CD 3]. None appeared directly related to pyridostigmine administration, and none of the patients had any overt symptoms of excessive parasympathetic activity. Median GI-2 was 2 (1-4) days.

CONCLUSION

Oral pyridostigmine appears to be safe to use after elective colorectal surgery in a select group of patients. However, considering this is a pilot study with a small sample size, larger controlled studies are needed to confirm this finding and establish efficacy for prevention of POI.