Acute Beta Blocker Overdose: Factors Associated with the Development of Cardiovascular Morbidity

Abstract

Objective: To identify factors in exposures to beta blockers (beta-adrenergic receptor antagonists) that are associated with the development of cardiovascular morbidity and contribute to disposition decisions from the emergency department. Methods: Prospective cohort of 280 beta blocker exposures reported to 2 regional poison centers. Multiple logistic regression was used to determine association of various clinical factors and outcome. Results: In this series of beta blocker exposures, 41 (15%) developed cardiovascular morbidity and 4 (1.4%) died. A history of cardioactive coingestant was the only factor significantly associated with the development of cardiovascular morbidity (p <. 05). When cases reporting cardioactive coingestants were excluded, a history of ingesting a beta blocker with membrane stabilizing activity was significantly associated with the development of cardiovascular morbidity (p <. 05). All those in whom the timing of symptoms could be determined, developed symptoms within 6 hours of ingestion. Conclusions: The single most important factor associated with the development of cardiovascular morbidity in beta blocker ingestion is a history of a cardioactive coingestant, primarily calcium channel blockers, cyclic antidepressants, and neuroleptics. In the absence of such co-ingestion, exposure to a beta blocker with membrane stabilizing activity is associated with an increased risk of cardiovascular morbidity. Beta blocker ingestion is unlikely to result in symptoms if the patient remains asymptomatic for 6 hours after the time of ingestion.