Pergamon The Journal of EmergencyMedicine, Vol 12, No 6, pp 799-802, 1994 Copyright 0 1994 Elsevim Science Ltd Printed in the USA. All rights reserved 0736-4679/94 $6.00 + .OO 0736-4679( 94)00083-2 Sd@Ct@d Topics: Toxicology BETA BLOCKER TOXICITY AFTER OVERDOSE: WHEN DO SYMPTOMS DEVELOP IN ADULTS? Jeffrey N. Love, MS, MD, FACEP Department of Emergency Medicine, Georgetown University Hospital, Washington, DC 0 Abstract-Published reports of beta blocker ingestions in adults are retrospectively reviewed to determine at what poiut posthtgestiou symptoms develop. Thirty-nine symp- tomatic beta blocker ingestfons were found. The patients ranged from 14 to 67 years of age. Thirty-one (80%) of those who demonstrated symptoms did so within 2 h of ingestion. This number rose to thirty-eight (97%) by 4 h postingestion. Only one patient developed symptoms after more then 4 b of asymptomatic observation. The develop- ment of bradycardia and first degree atrioventricular block during observation appeared to predict toxicity in this pa- tient who suddenly developed hypotension 6 h postinges- tion. No patfent required treatment for delayed cardiovas- cular depression if they remained asymptomatic during a 4-h period of observation postfngestion and demonstrated a normal electrocardiogram throughout. Whether the risk of delayed onset of toxicity after 6 h of asymptomatic ob- servation is sufficiently low to warrant “medical clearance” requires further investigation. 0 Keywords - adrenergic beta receptor blockaders; beta blocker intoxication INTRODUCTION Potentially toxic beta adrenergic blocker ingestions are relatively common emergency department presen- tations. Approximately 5,300 potential exposures were reported to the American Association of Poison Control Centers in 1992 (1). Many such ingestions are admitted to critical care units when no symptoms of intoxication are noted, presumably out of concern for delayed onset of toxicity. The question has been raised as to whether these patients are at risk for delayed toxicity if there are no symptoms during a 4- to 6-h period of observation (2). This retrospective literature review examines the length of time after ingestion it takes for symptoms to develop, attempts to define signs that may precede the development of symptoms, and searches for documented cases of delayed onset of toxicity. METHODS A retrospective review of the English medical litera- ture from 1963 through 1993 was performed by Med- line search for case presentations of beta blocker in- gestions. Criteria for entry included ingestions in those 14 years of age and older where beta blockers were believed to play a major role in toxicity and: 1. 2. The time from ingestion to the onset of symptoms (e.g. apnea, wheezing, decreased level of con- sciousness) was documented, or The patient was evaluated by a physician within 4 h of ingestion. Cases were excluded if: 1. The time of ingestion was unclear. 2. Patients presented with symptoms of toxicity more than 4 h after ingestion. 3. They involved sotalol ingestion. RECEIVED: 3 Januar 1994; 6 May 1 8 94 FINAL SUBMISSION RECEIVED: 6 ACCEPTED: April 1994;