When Agitation Meets Intoxication: A Retrospective Comparison of Intramuscular Olanzapine and Haloperidol Among Patients With and Without Substance Use in a Psychiatric Emergency Service

Abstract

Background:

Substance use is a major contributor to psychiatric emergencies, often complicating the management of acute agitation. Despite the high prevalence of co-occurring substance use in emergency psychiatric settings, evidence guiding pharmacologic interventions remains limited. This study examined whether active substance use, as measured by urine drug screening (UDS), predicted clinical and safety outcomes among patients requiring intramuscular (IM) medication for agitation in an emergency psychiatric setting.

Methods:

This retrospective chart review included 103 patients presenting to a Comprehensive Psychiatric Emergency Program (CPEP) between January 2020 and November 2022 who received IM haloperidol lactate (HL) or IM olanzapine (OL) and completed UDS. Patients with positive (UDS+) screens were compared to those with negative (UDS−) screens on demographic, clinical, and medication-related outcomes. Primary medication outcomes were the need for repeat IM medication administration and time to next administration. Secondary measures included physiologic changes, adverse effects, and restraint/seclusion use.

Results:

Fifty-eight patients (56.3%) had a positive UDS. The UDS+ group was younger and more frequently had an incarceration history, but did not differ from the UDS− group in terms of diagnoses, hospitalization history, or adverse events. UDS+ patients had a significantly longer time to next medication administration (mean 10.0 vs 6.5 hours, P = .050). There were no differences in terms of repeat IM use, objective measures of agitation, or safety outcomes. Subanalysis comparing HL and OL among UDS+ patients was limited by sample size, but showed comparable efficacy and tolerability.

Conclusions:

Patients with active substance use exhibited similar or greater responses to standard IM treatment for agitation without increased safety concerns. Findings support potential safety and efficacy of common pharmacologic approaches in this high-risk population, though a modest single-site cohort may limit generalizability. There is a need for prospective, multisite replication.