Neostigmine in acute colonic pseudo obstruction

 Q: What are the few options to decrease the side effects of Neostigmine when used to relieve acute colonic pseudo-obstruction, popularly known as Ogilvie's syndrome? 

 Answer: Neostigmine is an acetylcholinesterase inhibitor and is very effective in patients with acute colonic pseudo-obstruction, especially patients who fail conservative measures for 2-3 days or have cecal diameter > 12 cm. Some of the side effects are bradycardia going towards asystole (atropine is recommended to be available at the bedside), seizures, restlessness, tremor, salivation, sweating, bronchoconstriction, abdominal cramps, nausea, and vomiting. Few strategies to minimize the side effects are 

• Inject slowly over 5 minutes
• Keep patient supine (with bedpan to decrease the nuisance of stool passage)
• Decrease the dose to 1.5 mg or even to 0.5-1 mg in high-risk patients 
• Co-administration of glycopyrrolate which is an anticholinergic agent with minimal effect on the muscarinic receptors of the colon

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References:

1. Naveed M, Jamil LH, Fujii-Lau LL, et al. American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in the management of acute colonic pseudo-obstruction and colonic volvulus. Gastrointest Endosc 2020; 91:228. 

2. Saunders MD, Kimmey MB. Systematic review: acute colonic pseudo-obstruction. Aliment Pharmacol Ther 2005; 22:917. 

3. Kram B, Greenland M, Grant M, et al. Efficacy and Safety of Subcutaneous Neostigmine for Ileus, Acute Colonic Pseudo-obstruction, or Refractory Constipation. Ann Pharmacother 2018; 52:505. 

4.  Korsten MA, Rosman AS, Ng A, et al. Infusion of neostigmine-glycopyrrolate for bowel evacuation in persons with spinal cord injury. Am J Gastroenterol 2005; 100:1560.