Selected topics: toxicology
Are 1–2 tablets dangerous? Beta-blocker exposure in toddlers

Series Editors: Jeffrey N. Love, md, The Georgetown University Emergency Department, Washington, DC; Wendy Klein-Schwartz, pharmd, The Maryland Poison Center, Baltimore, MD; Liesl Curtis, md, The Georgetown University Emergency Department, Washington, DC.
https://doi.org/10.1016/j.jemermed.2003.11.015Get rights and content

Abstract

The common use and wide availability of beta-adrenergic blocking agents make them frequent ingestants for small children. Yet, there are no clear guidelines in the literature to direct the care of the toddler with the history of ingesting 1–2 tablets. With 40 years of extensive clinical experience, not one documented case of death or serious cardiovascular morbidity as a direct result of a beta-blocker exposure is to be found in an English language review for children under 6 years of age. As with children on chronic beta-blocker therapy, several cases of symptomatic hypoglycemia associated with a single acute propranolol exposure suggest a vulnerability to this complication. Though the risk to the toddler exposed to 1–2 tablets appears to be extremely small, several factors mitigate the actual risk to the child and the need for triage to a health care facility.

Introduction

There are a wide variety of therapeutic indications for beta-adrenergic antagonists, better known as beta-blockers. They are most commonly used in cardiovascular disease. Other indications include migraine headache, tremor, panic attacks, and as medications to decrease intraocular pressures. In the pediatric population, beta-blockers are used primarily to treat hypertension, dysrhythmias, thyrotoxicosis, and migraine headache (1). Propranolol, the agent most commonly associated with overdose and toxicity, was released in 1964. By the 1970s there were 10 beta-blockers on the market that were widely used in the United States as anti-hypertensives and anti-anginal agents (2).

As the availability of this class of medication has increased, so have reports of overdose and toxicity. This article reviews the available literature of adverse events from beta-blocker exposure in toddlers. Included is a basic overview of the pathophysiology, pharmacokinetics, and treatment of beta-blocker intoxication. Finally, based on the available literature, risk is assessed and guidelines are presented for medical evaluation and disposition of children under 6 years of age who may have ingested 1–2 tablets.

Section snippets

Characteristics of beta-blockers

Beta-blockers are competitive antagonists of catecholamines at beta-adrenergic receptors. There are at least two subtypes of beta-adrenergic receptors, beta-1 and beta-2. Some beta-blocking agents are designed to selectively act at either the beta-1 or the beta-2 receptor. At low doses, medications such as atenolol and metoprolol are beta-1 selective; however, in larger doses, they lose their selectivity and act at both beta-1 and 2 receptors (3). In addition, beta-blockers also possess the

Management of serious beta-blocker overdose

Patients with suspected significant beta-blocker overdose or toxicity should be placed on a cardiac monitor, have frequent blood pressure monitoring, a 12-lead electrocardiogram (EKG), and a serum glucose determination. If congestive heart failure is suspected, a chest radiograph and oxygen saturation should be obtained. Serum beta-blocker levels may be helpful in questionable cases to establish a diagnosis (16). These levels are generally performed as a “send out” test by a reference

Beta-blocker toxicity in children

The annual number of beta-blocker exposures reported to the American Association of Poison Control Centers (AAPCC) has increased approximately fivefold in children under 6 years old over the last 19 years 21, 22. This is likely due to increased reporting to poison control centers and increased availability of these drugs. According to data from the AAPCC, for children under the age of 6 years, there were 37,066 reported exposures to beta-blockers between 1983 and 2001 21, 22, 23, 24, 25, 26, 27

Recommendations

There is no study that clearly defines the risk of toxicity in the toddler who ingests a beta-blocker. This likely explains why a recent survey of poison centers found no consistent triage practice in beta-blocker exposures involving children under 6 years of age (31). Beta-blockers have been in clinical use for nearly 40 years and are common exposures reported to the American Association of Poison Control Centers. With this extensive experience, there are no published deaths in toddlers as a

Summary

Exposure to 1–2 tablets of beta-blocker appears to place the toddler at very little risk of mortality or serious morbidity. A convincing argument can be made for home management without gut decontamination in those with a clear history of no more then two tablets of hydrophilic beta-blockers. The need for hospital evaluation after exposure to 1–2 tablets of a lipophilic agent should be made on a case-by-case basis. Although uncommon, hypoglycemia remains a concern. Encouraging oral caloric

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