Human bromethalin exposures reported to a U.S. Statewide Poison Control System

Abstract

Background: Bromethalin is an increasingly used alternative to long-acting anticoagulant and cholecalciferol rodenticides. There are few reports of human exposures, and no existing professional society guidelines on medical management of bromethalin ingestions. The aim of this retrospective data review is to characterize bromethalin exposures reported to the California Poison Control System (CPCS) between 1997 and 2014. Methods: This is an observational retrospective case review of our statewide poison control system’s electronic medical records. Following Institutional Board Review and Research Committee approvals, poison center exposures related to bromethalin were extracted using substance code and free text search strategies. Case notes of bromethalin exposures were reviewed for demographic, clinical, laboratory, and outcome information; inclusion criteria for the study was single-substance, human exposure to bromethalin. Results: There were 129 calls related to human bromethalin exposures (three cases met exclusion criteria). The age range of cases was 7 months–90 years old, with the majority of exposures (89 cases; 70.6%), occurring in children younger than 5 years of age (median age of 2 years). Most exposures occurred in the pediatric population as a result of exploratory oral exposure. One hundred and thirteen patients (89.7%) had no effects post exposure, while 10 patients (7.9%) had a minor outcome. Adverse effects were minor, self-limited, and mostly gastrointestinal upset. There were no moderate, major, or fatal effects in our study population. The approximate ingested dose, available in six cases, ranged from 0.067 mg/kg to 0.3 mg/kg (milligrams of bromethalin ingested per kilogram of body weight), and no dose-symptom threshold could be established from this series. Exposures were not confirmed through urine or serum laboratory testing. Discussion: The prognosis for most accidental ingestions appears to be excellent. However, bromethalin exposures may result in a higher number of symptomatic patients than long-acting anticoagulant agents. Parents, physicians and poison control specialists are encouraged to maintain a high index of suspicion for bromethalin-related complications in all cases of rodenticide exposures. Conclusions: Accidental bromethalin exposures in children appear to be self-limited in toxicity. Additional studies are warranted to determine whether more severe effects are precipitated when larger amounts are involved, particularly in suicidal ingestion.