The aim of this analysis was to update a previous publication which assessed the respective botulinum toxin A (BoNT-A) agents for associations with overdose as well as explore any association with medication errors.

A previously published manuscript showed a 73-fold higher relative odds ratio for overdose with abobotulinumtoxinA versus other BoNT-A agents. This analysis has two additional years of data included that has been published since original analysis.

The Food and Drug Administration Adverse Event Reporting System (FAERS) was utilized. The analysis was conducted on data between March 2014 and June 2019. BoNT-A cases were included when they were considered the “Primary Suspect” drug. Overdose was defined as incidence of ‘Overdose’ being reported as an adverse event. Primary outcome was incidence of ‘Overdose’ compared within the respective agents. Rates of overdose having a concomitant medication error were also reported between agents. Medication error was defined as having a concomitant report of 'Product preparation error' and/or ‘Wrong technique in product usage process'.

A total of 6,432,493 unique adverse events were reported during the study period for all drugs in the FAERS database. Of which, 23,789 were BoNT-A cases. The rate of adverse events involving overdose for abobotulinumtoxinA (14.2%; 342/2,415) was significantly higher than both onabotulinumtoxinA (0.4%; 78/20,113; p < 0.0001) and incobotulinumtoxinA (<0.1%; 1/1,261; p < 0.0001). Additionally, a large percentage of abobotulinumtoxinA overdoses (37.1%; 127/342) had concomitant report of a medication error.  This phenomenon was not seen with onabotulinumtoxinA (1.3%; 1/78) or incobotulinumtoxinA (0.0%; 0/1) overdoses.

The analysis validates earlier findings which showed abobotulinumtoxinA adverse events were significantly associated with overdose versus other BoNT-A agents. Furthermore, abobotulinumtoxinA overdoses were associated with medication errors. The FAERS database cannot establish causal relationships; however the analysis did identify safety signals that future studies should venture to confirm.