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We thank Drs Mistry and Nair for their interest in our recent publication examining the implications of removing liposomal bupivacaine from an academic hospital formulary.1 2 Their five itemized comments can be reasonably distilled into two overarching themes. First, they highlight the inherent potential for unmeasured, time-varying confounding in a retrospective interrupted time-series analysis. Second, they suggest that the inclusion of additional outcomes could further strengthen the interpretability and scope of the findings.