Management of acutely agitated patients can present a challenge both in the field and in the emergency department. There are a variety of techniques that can be used to manage agitated behavior in the prehospital setting, including verbal management techniques and physical restraints. This discussion will focus on chemical restraint of the acutely agitated patient.
In September 2009, the American College of Emergency Physicians' Task Force on Excited Delirium published a white paper that concluded that some episodes of excited delirium "may be amenable to early therapeutic intervention in some cases in the pre-mortem state," and that "physical restraints should be rapidly supplemented with chemical restraints" in agitated patients who require restraint.1 Options for chemical sedation in the prehospital setting include benzodiazepines, antipsychotics (also called neuroleptics), antihistamines and, rarely, dissociative agents such as ketamine. A survey of 34 larger metropolitan city EMS agencies at the annual Gathering of Eagles conference revealed that 33 of these agencies use some method of chemical restraint. Of those, 26 use midazolam (Versed), nine use diazepam (Valium), four use lorazepam (Ativan), eight use haloperidol (Haldol), two use droperidol (Inapsine), and one uses ketamine. (Some agencies have more than one agent available for chemical sedation.)
While benzodiazepines are excellent agents in many settings, particularly to treat patients with acute agitation related to cocaine or methamphetamine ingestion, they may not be ideal in all situations. Antipsychotics are also effective in managing agitated behavior and may result in fewer episodes of oversedation.2 In particular, antipsychotics may be a better choice when dealing with agitated behavior related to alcohol use or psychiatric conditions. There are both typical antipsychotics such as haloperidol and droperidol and newer, atypical antipsychotics such as ziprasidone (Geodon) and olanzapine (Zyprexa).
First introduced in the United States in 1970, droperidol is a butyrophenone and a potent antagonist of dopamine subtype 2 receptors in the limbic system. It is a potent antipsychotic used both for chemical restraint and as an antiemetic. Droperidol has been shown to be an effective sedative agent with few treatment failures and no respiratory depression.3,4 It has also been shown to be safe in a variety of clinical settings, including emergency management of acute agitation.5-7 In a randomized controlled trial, droperidol was found to result in more rapid control of agitated patients than haloperidol, with no increase in undesirable effects.8 In another trial comparing droperidol to midazolam, no difference was found in the onset of adequate sedation, but patients receiving midazolam showed an increased need for active airway management.9
So why is droperidol not more widely used in EMS? In December 2001, the FDA issued a "black box" warning for the drug based on reports of QT prolongation and/or torsade de pointes in patients receiving it. This warning came after more than 30 years of clinical use, making it the longest latency period from initial FDA approval to black box warning to date. The warning was also issued despite the fact that no clinical trial or systematic review had reported any adverse cardiac events. It resulted in a dramatic decrease in the use of droperidol across the country despite a number of published articles questioning the warning's validity.10-13 Among the conclusions of these articles was that "the evidence is not convincing for a causal relationship between therapeutic droperidol administration and life-threatening cardiac events," and that "the black box warning appears to have originated from post-marketing surveillance data rather than data reported in peer-reviewed medical literature." Hennepin County, MN, published a review in 2005 concluding that since the removal of droperidol from its system as a treatment option for out-of-hospital agitated patients, it had seen an increased frequency of continuous pulse oximetry monitoring, intubation, ED critical care management and ICU admission.14