A naturalistic study of intramuscular haloperidol versus intramuscular olanzapine for the management of acute agitation

J Clin Psychopharmacol. 2012 Jun;32(3):317-22. doi: 10.1097/JCP.0b013e318253a2fe.


Objective: Published research on agitation is limited by the difficulty in generalizing findings from trials using moderately agitated, carefully selected patients treated with single agents. More specifically, there are few comparative studies examining common intramuscular (IM) regimens (ie, haloperidol with or without benzodiazepines) with IM atypical antipsychotics. Therefore, we conducted a retrospective chart review to compare IM olanzapine and haloperidol in a "real-world" population with agitation.

Method: We performed a retrospective evaluation of charts from 146 consecutive emergency department patients who received either IM haloperidol or IM olanzapine for agitation. We used a clinically oriented proxy marker of efficacy--the necessity for additional medication intervention for agitation (AMI)--as our primary outcome measure.

Results: Additional medication intervention for agitation was required by 43% (13/30) patients when haloperidol was given alone and by 18% (13/72) when haloperidol was given with a benzodiazepine. In the case of olanzapine, AMI was required by 29% (6/21) of patients receiving olanzapine alone and by 18% (2/11) of patients given olanzapine plus a benzodiazepine. A significant percentage of patients had clinical characteristics (nonpsychiatric triage complaint, drug/alcohol use, severe agitation) that differ from more selective samples.

Conclusions: Overall, these finding suggest that in a naturalistic emergency department setting, haloperidol monotherapy is less effective--at least in requiring AMI--than olanzapine with or without a benzodiazepine or haloperidol plus a benzodiazepine. Moreover, these later 3 regimens seemed comparable. Prospective studies examining the treatment of real-world agitation, including head-to-head comparisons of the haloperidol-benzodiazepine combination with newer IM antipsychotics, are needed.

Publication types

  • Comparative Study
  • Multicenter Study

MeSH terms

  • Acute Disease
  • Adult
  • Antipsychotic Agents / administration & dosage
  • Antipsychotic Agents / adverse effects
  • Antipsychotic Agents / therapeutic use*
  • Benzodiazepines / administration & dosage
  • Benzodiazepines / adverse effects
  • Benzodiazepines / therapeutic use*
  • Dose-Response Relationship, Drug
  • Drug Therapy, Combination / adverse effects
  • Emergency Service, Hospital
  • Female
  • Haloperidol / administration & dosage
  • Haloperidol / adverse effects
  • Haloperidol / therapeutic use*
  • Humans
  • Injections, Intramuscular
  • Male
  • Medical Records
  • Middle Aged
  • Olanzapine
  • Psychomotor Agitation / complications
  • Psychomotor Agitation / drug therapy*
  • Retrospective Studies
  • Substance-Related Disorders / complications


  • Antipsychotic Agents
  • Benzodiazepines
  • Haloperidol
  • Olanzapine