P0537 - Bowel Regimen Gone Rogue: A Rare Case of Anaphylaxis Secondary to Over-the-Counter Polyethylene Glycol 3350

Abigail L. Ellington, MD, Jigisha Srivastav, MD, Corey Williams, MD
Atrium Health Wake Forest Baptist, Winston-Salem, NC

Introduction: Polyethylene glycol 3350 (PEG) is a common agent used for bowel preparation before colonoscopy or other lower GI endoscopies. It is also readily available over the counter for constipation. It is generally well-tolerated. Below, we present a case of a patient who had anaphylaxis secondary to PEG.

Case Description/

Methods: A 57-year-old male with CAD, HTN, HLD, and diabetes presented to the ED with hypotension, nausea, and diffuse itchiness 4 hours after taking PEG for preoperative constipation. Within 5 minutes of ingestion, he developed diffuse pruritus and a rash on the arms and legs. He took oral diphenhydramine with minor relief, prompting his ED visit. On arrival, he was tachycardic (HR 95), tachypneic (RR 29), and hypotensive (BP 83/58-- >77/59). Workup showed normal white blood cell count, normal hemoglobin, and normal platelets; however, lactic acid was elevated to 5.6. He was given IV methylprednisolone sodium succinate 125mg, IV famotidine 20mg, IV diphenhydramine 25mg and started on an epinephrine infusion. He was admitted to the ICU where he subsequently recovered. He had surgery a few days later.

Discussion: PEG is widely used for bowel preparation, with most patients tolerating it well. It is also frequently prescribed for constipation and is found in more than 1,000 FDA-approved medications, including contraceptives, antihypertensives, antibiotics, and diabetes drugs¹. A review of literature identified only 53 reports between 2005 and 2017 in which PEG was suspected to be the cause of an anaphylactic reaction with an average of only 4 cases per year from 2005 to 2017¹. Most reactions occurred during colonoscopy prep, though about ¼ occurred during constipation treatment¹. While rare, PEG should remain on differential as a cause of anaphylaxis, and alternative bowel regimens should be considered for patients with a history of reaction. Options without polyethylene glycols or polysorbates include sodium picosulfate, magnesium oxide, anhydrous citric acid; sodium phosphate tablets; oral sulfate solution/tablets; magnesium citrate; bisacodyl; and off label lactulose².

Citations: (1) Stone et al. Immediate Hypersensitivity to Polyethylene Glycols and Polysorbates: More Common Than We Have Recognized. Aug 2019. DOI: 10.1016/j.jaip.2018.12.003. (2) Jacobson et al. Optimizing Bowel Preparation Quality for Colonscopy: Consensus Recommendations by the US Multi-Society Task Force on Colorectal Cancer. April 2025. DOI: 10.1053/j.gastro.2025.02.002.

Disclosures:
Abigail Ellington indicated no relevant financial relationships.
Jigisha Srivastav indicated no relevant financial relationships.
Corey Williams indicated no relevant financial relationships.

Abigail L. Ellington, MD, Jigisha Srivastav, MD, Corey Williams, MD. P0537 - Bowel Regimen Gone Rogue: A Rare Case of Anaphylaxis Secondary to Over-the-Counter Polyethylene Glycol 3350, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.