Neostigmine for the treatment of acute colonic pseudo-obstruction

Background Acute colonic pseudo-obstruction that is, massive dilation of th e colon without mechanical obstruction - may develop after surgery or sever e illness. Although it may resolve with conservative therapy, colonoscopic decompression is sometimes needed to prevent ischemia and perforation of th e bowel, Uncontrolled studies have suggested that neostigmine may be an eff ective treatment. Methods We studied 21 patients with acute colonic pseudo-obstruction. All h ad abdominal distention and radiographic evidence of colonic dilation, with a cecal diameter of at least 10 cm, and had had no response to at least 24 hours of conservative treatment. We randomly assigned 11 to receive 2.0 mg of neostigmine intravenously and 10 to receive intravenous saline. A physi cian who was unaware of the patients' treatment assignments recorded clinic al response (defined as prompt evacuation of flatus or stool and a reductio n in abdominal distention), abdominal circumference, and measurements of th e colon on radiographs. Patients who had no response to the initial injecti on were eligible to receive open-label neostigmine three hours later. Results Ten of the 11 patients who received neostigmine had prompt colonic decompression, as compared with none of the 10 patients who received placeb o (P<0.001). The median time to response was 4 minutes (range, 3 to 30). Se ven patients in the placebo group and the one patient in the neostigmine gr oup without an initial response received open-label neostigmine; all had co lonic decompression. Two patients who had an initial response to neostigmin e required colonoscopic decompression for recurrence of colonic distention; one eventually underwent subtotal colectomy. Side effects of neostigmine i ncluded abdominal pain, excess salivation, and vomiting. Symptomatic bradyc ardia developed in two patients and was treated with atropine. Conclusions In patients with acute colonic pseudoobstruction who have not h ad a response to conservative therapy, treatment with neostigmine rapidly d ecompresses the colon. (N Engl J Med 1999;341: 137-41.) (C) 1999, Massachus etts Medical Society.