Withdrawal from opioids is a clinical scenario that emergency department physicians encounter frequently. Patients who present with opioid withdrawal display symptoms such as agitation, anxiety, myalgias, abdominal pain, diarrhea, nausea, and vomiting. Currently, the standard treatment for opioid withdrawal is clonidine (an alpha-2 adrenergic agonist), as well as supportive cares (anti-emetics, intravenous fluids). Olanzapine is an atypical antipsychotic that is given frequently in the ED for many of the same symptoms that are seen in patients who are experiencing opioid withdrawal, however its use in this toxidrome has never been studied. The hypothesis of this study is that olanzapine is a safe and efficacious option when compared to clonidine for the treatment of opioid withdrawal in the emergency department.

This study will be a randomized control trial where patients will be randomized to receive intramuscular olanzapine or oral clonidine as the first intervention given for treatment of opiate withdrawal. This study will not be blinded.

Screening and enrollment: Research Associates will screen patients by review of the electronic medical record. When these patients are identified, the RA will approach the CITI trained ED provider who will obtain written informed consent. Allergies to either medication will be screened for in Epic by the research associates. Allergies will also be verified by the provider who is completing the consent.

Study protocol: If the patient consents to enroll in the study, the research associate will randomize the patient to receive olanzapine or clonidine as the first treatment intervention. The ED provider will then order that medication for the patient and will it be administered by nursing staff. At this time the provider may order the patient to have a peripheral IV placed and IV fluids administered at their discretion. No other supportive measures (anti-emetics, non-narcotic pain medications) may be given at this time.

Prior to medication administration, the research associate will assess the patient's withdrawal symptoms using the Clinical Opiate Withdrawal Scale for withdrawal symptoms. This is a validated tool used to assess degree of withdrawal symptoms by evaluating physiologic and symptomatic parameters. The medical provider will also obtain information regarding the patients opioid use history (what type of opioid used, chronicity of use, date and time of last use). After the study medication administration, patients will be observed for clinical improvement. At 30 minutes, additional medications or interventions may be prescribed at the discretion of the ED provider for symptom control, including crossover of the study medications. The research associate will record which other medications/interventions were ordered, the indication for these interventions, and times administered.

Symptoms will be re-assessed by the research associate using the COWS at 60 minutes, 120 minutes post administration of the initial treatment intervention, as well as at 4 hours post administration (approximately time of discharge from the emergency depatment). At these same time marks, sedation of the patient will be assessed using the overt agitation severity scale (OASS). Throughout the patient's ED stay, the research associate will be monitoring for adverse complications such as allergic reaction, dystonia, akathisia, respiratory complications, or hypotension.

The investigators will conduct preliminary data analysis after the first 25 and 50 patients are enrolled, respectively. Initial power analysis and sample size calculations delineated that the investigators would need 35 patients per arm to detect a 50% difference in the need for rescue medication at 1 hour between the two study medications.

Inclusion Criteria:

• Any patients who present to the emergency department where the providers are concerned for opioid withdrawal contributing to their symptoms on presentation is eligible for inclusion.

Exclusion Criteria:

• Age less than 18
• Allergy to either medication (olanzapine, clonidine)
• Inability to give informed consent
• Known pregnancy

Adverse event data was collected for the duration of the ED encounter, on average within 6 hours

AEs including hypotension (that resolved without treatment other than fluids), and extrapyramidal side effects are NOT CONSIDERED serious adverse events