Acute Colonic Pseudo-obstruction Following Massive Bupropion Overdose

Bupropion is an atypical antidepressant that inhibits norepinephrine and dopamine reuptake. Poison control data demonstrate toxic effects at doses as low as 600 mg. Common adverse effects of overdose include tachycardia, seizures, and cardiac arrhythmias. Gastrointestinal complications are rarely described. Our case shows an 18-year-old male presented to the emergency department after witnessed seizure-like activity. Family reported ingestion of approximately thirty 300-mg sustained-release bupropion tablets 4-5 hours prior to presentation. On arrival, he required endotracheal intubation for airway protection. Sedation was initiated with propofol and fentanyl; fentanyl was rapidly discontinued. Given delayed presentation and sustained-release ingestion, whole bowel irrigation was initiated with nasogastric administration of 50 g activated charcoal followed by 6 L polyethylene glycol-electrolyte solution. Subcutaneous methylnaltrexone (12 mg) was administered to reverse potential opioid-related ileus without effect. Worsening abdominal distension prompted contrast-enhanced computed tomography of the abdomen and pelvis, which demonstrated diffuse fluid-filled colonic distension with distal small bowel dilation and no evidence of mechanical obstruction or pill bezoar. Gastroenterology performed colonoscopic decompression with rectal tube placement. This resulted in successful decompression. The patient was extubated the following day with return of bowel function on post-decompression day two. In supratherapeutic states, bupropion exhibits anticholinergic properties through poorly understood mechanisms, which may impair intestinal motility. Colonic complications remain rare, with only isolated reports describing colonic ischemia or pseudo-obstruction associated with bupropion toxicity. Clinicians should consider severe gastrointestinal dysmotility when managing sustained-release bupropion toxicity.