Acute beta blocker overdose: Factors associated with the development of cardiovascular morbidity

Objective: To identify factors in exposures to beta blockers (beta-adrenerg ic receptor antagonists) that are associated with the development of cardio vascular morbidity and contribute to disposition decisions from the emergen cy department. Methods: Prospective cohort of 280 beta blocker exposures re ported 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 cardiovascula r morbidity (p <.05). When cases reporting cardioactive coingestants were e xcluded, a history of ingesting a beta blocker with membrane stabilizing ac tivity was significantly associated with the development of cardiovascular morbidity (p <.05), All those In whom the timing of symptoms could be deter mined, developed symptoms within 6 hours of ingestion. Conclusions: The sin gle most important factor associated with the development of cardiovascular morbidity in beta blocker ingestion is a history of a cardioactive coinges tant, primarily calcium channel blockers, cyclic antidepressants, and neuro leptics, In the absence of such coingestion, exposure to a beta blocker wit h membrane stabilizing activity is associated with an increased risk of car diovascular morbidity. Beta blocker ingestion is unlikely to result in symp toms if the patient remains asymptomatic for 6 hours after the time of inge stion.