(967) A "Bezoar" Case of TCA Overdose!

Introduction: Drug overdose deaths involving antidepressants have risen steadily over the past 20 years. Between 2000-2015, the tricyclic antidepressant (TCA) amitriptyline alone was estimated to account for nearly 40% of all antidepressant associated deaths. While toxicity of TCAs has been well established, attention should be given to factors that delay their clearance through the gastrointestinal tract, increasing their mortality risk and hospitalization time.

Description: We report the case of a 37-year-old female who presented after an intentional multidrug overdose with an estimated 3-month supply of Amitriptyline 150mg as well as Alprazolam, Methadone, and Zolpidem of unclear amount. In the ED she was initially hemodynamically stable but became progressively more obtunded and hypotensive prompting intubation and eventual placement on pressors. Her initial EKG demonstrated a prolonged QRS of 128ms, and she was placed on a bicarbonate drip and transferred to the ICU. Her pressor requirements resolved after 4 days in the setting of transient depression of bilateral systolic ventricular function consistent with TCA toxicity. She was administered Keppra for seizure activity seen on EEG. She continued to require bicarbonate for a total of 13 days for persistently prolonged QRS on serial EKGs. Her abdomen was notably increasingly distended and intermittently tense so abdominal imaging was done and showed constipation and hyperdense material concerning for a pharmacobezoar; Osmotic laxatives were started with improvement of her constipation and QRS. She was extubated and transferred out of the ICU 3 days later.

Discussion: Our case demonstrates how prolonged TCA toxicity should prompt suspicion for formation of a pill bezoar. TCAs are rapidly absorbed in the gut and reach peak concentration at approximately 6 hours. At supratherapeutic levels, anticholinergic effects of TCA may significantly slow down gastric motility and promote formation of a pill bezoar resulting in delayed or multiple peak concentrations. Clearance of the bezoar is necessary for overdose management and may be achieved with a bowel regimen with osmotic laxatives. While aggressive measures like endoscopic removal are possible, breakage of the bezoar should be avoided to protect against massive dose exposure and severe toxicity.