Safety of Physostigmine for Pediatric Antimuscarinic Poisoning

Physostigmine fell out of widespread use in the 1980s due to safety concerns; however, more recent research has demonstrated that its safety profile is better than previously thought. These studies have mainly included adults. We theorized that improved safety data may lead to more acceptance. Our objectives, therefore, were to characterize current frequency of use of physostigmine in pediatric patients as well as to study adverse effect rates in a national pediatric patient population.

The National Poison Data System was queried for cases of patients aged 0-18 years that involved single-substance exposures to antimuscarinic xenobiotics that were reported to a poison center between January 1, 2000, and December 31, 2020. Cases were stratified into groups by therapy received: benzodiazepines alone, benzodiazepines and physostigmine, physostigmine alone, or no physostigmine or benzodiazepines. Patient demographics, clinical effects, and medical outcomes were analyzed.

A total of 694,132 cases were reviewed, and 150,075 were included for analysis. Nearly 5% (7562/150,075) of patients received specific pharmacological therapy with benzodiazepines, physostigmine, or both. A benzodiazepine as a single agent was the most frequently used pharmacologic therapy (92% of 7562). Among patients receiving any pharmacological therapy, only 8.3% (n = 627) of patients received physostigmine. Frequency of serious outcomes significantly increased across the study period among patients receiving benzodiazepines alone or with physostigmine. There was no increase in serious outcomes among patients receiving only physostigmine.

Physostigmine frequency of use was low overall, but when used, was associated with less severe outcomes when compared to benzodiazepines.