Does the time between doses in an unintentional double dose bupropion exposure affect the incidence of adverse effects? A retrospective cohort study.

Introduction: Unintentional therapeutic errors with bupropion are common. The impact of the timing of the second dose in a double dose exposure on adverse effects is not well studied. This study aims to compare adverse effects between double doses separated by <720 min and ≥720 min.

Methods: This was a retrospective cohort study of unintentional double dose bupropion ingestions in patients reported to a regional poison center between January 2018 and December 2022. Patients were included if the double dose was their own medication, unintentional, and a single substance exposure. Data collected included age, gender, bupropion formulation, prescribed home dose, dosing error details, time between doses, caller site, referral to the emergency department, patient observation at healthcare facilities, clinical effects, and outcome.

Results: Among 663 cases screened, 294 met inclusion criteria. The majority involved extended-release preparations (69.0%). Seventy-four were observed in a healthcare facility and monitored for 24 h from initial dose. The incidence of seizures was 5.3%, including one case not observed for a full 24 h. There was no significant difference in the incidence of seizures (2.7% versus 7.7%), tachycardia (27.0% versus 30.8%), hypertension (18.9% versus 38.5%) other signs/symptoms (27.0% versus 23.1%), or any signs/symptoms (48.6% versus 61.5%) between double doses of extended release bupropion separated by <720 min and those separated by ≥720 min, respectively.

Discussion: In patients with double dose exposures to extended-release bupropion, it does not appear that the timing of the second dose can be used to risk-stratify patients. Our data are limited by sample size.

Conclusion: In this study, the time between double doses of bupropion did not affect the incidence of seizure, tachycardia, hypertension, other signs/symptoms, or any signs/symptoms. Larger, prospective studies investigating this difference would strengthen our understanding and management of these patients.