Clinical characteristics and outcomes associated with bupropion overdose: a Canadian perspective

Background: Therapeutic use, overdose and recreational abuse of bupropion are increasing. The purpose of this study was to describe the incidence and outcomes of bupropion exposures reported to the Ontario Poison Centre in Canada, and to identify predictors of seizures. Methods: This was a retrospective, chart review of bupropion exposures reported to the Ontario Poison Centre between 2013 and 2015. Extracted variables included demographics, formulation and dose of bupropion ingested, co-ingestants, timing of exposure, provided treatments, clinical characteristics on presentation (i.e. tachycardia, ECG changes), onset of seizures following exposure, and clinical outcomes (i.e. admission to hospital, ICU admission, intubation, death). Data were compared between patients who had a benzodiazepine co-ingestion and those that had a seizure using descriptive statistics. A multivariable logistic regression was then conducted to determine predictors of seizure. Results: In this study, there were 1,065 reported bupropion overdoses. Among patients with reported outcomes, 51.9% of patients had episodes of tachycardia, (23.9% of patients had ECG changes, and 17.3% of patients experienced a seizure. The dose of bupropion ingested was significantly associated with the odds of seizure, with a 13% increased odds of seizure for every 20 mg/kg increase in bupropion dose (Odds Ratio [OR] = 1.13, 95% CI = 1.05-1.21). Co-ingestion of benzodiazepines reduced the odds of seizure by over 60% (OR = 0.32, 95% CI = 0.15-0.69). Conclusion: Our findings contribute to the existing clinical toxicology literature by describing specific characteristics and outcomes of patients with acute bupropion overdoses. Patients were less likely to experience a seizure if they had co-ingested benzodiazepines.