Use of Intramuscular Midazolam, Diphenhydramine, and Haloperidol in Acute Agitation Management in a Psychiatric Emergency Department.

Background: Intramuscular (IM) lorazepam is administered to acutely agitated patients. During a lorazepam shortage, midazolam was selected as the IM benzodiazepine of choice at this study location. This study aims to explore the efficacy and safety of IM haloperidol, diphenhydramine, and midazolam in treating acutely agitated patients.

Methods: A single center, retrospective chart review was conducted in adult patients who received IM diphenhydramine and haloperidol in combination with either midazolam (midazolam+) or lorazepam (lorazepam+) in a psychiatric emergency department (ED) during 2 identified lorazepam shortage periods. Multivariate ordinary least squares and logistic regression analyses were used to evaluate post-IM patients' conditions in behavioral activity rating scale (BARS) scores and the safety and tolerability of IM administrations.

Results: A total of 174 patients met inclusion criteria, with 87 patients in the midazolam+ group (treatment) and 87 patients in the lorazepam+ group (control). Lorazepam+ was associated with a 9.4% greater decrease in BARS score than midazolam+ ( P <0.01). Midazolam+ administrations achieved a goal BARS score of 4 more frequently than lorazepam+ ( P <0.05). 18.4% more patients received a BARS score of 2, oversedation with lorazepam+ ( P <0.05). Lorazepam+ patients took nearly 3 hours (176 min) longer than midazolam+ to return to "normal" baseline behavior ( P <0.001). No statistically significant differences were detected in the incidence of hypotensive episodes or oxygen desaturation between groups.

Conclusions: This is the first study to examine coadministration of intramuscular midazolam with haloperidol and diphenhydramine. Midazolam+ was effective at managing agitation and may be an alternative to lorazepam+.