In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. To demonstrate the challenges with current diagnosis and treatment strategies for precipitated opioid withdrawal secondary to naloxone the emergency department (ED) setting and describe the role of the emergency medicine (EM) pharmacist in its management. There are no standardized criteria to define precipitated opioid withdrawal syndrome, so the diagnosis is typically based on sentinel signs and symptoms and time course. Complicating factors include a positive urine toxicology screen for nonopioid substances, comorbidities and associated medications prior to admission, medications given in the ED, and a fluctuating patient course during the ED stay that likely involves all these issues. Although buprenorphine is frequently recommended as the primary treatment for precipitated withdrawal, its use can be complicated if patients are on methadone maintenance or other long-acting opioids. The EM pharmacist plays a key role in managing patients with precipitated withdrawal. Practice changes related to the diagnosis and treatment of opioid use disorder (OUD) with precipitated withdrawal in the ED are needed. EM pharmacists as part of the interprofessional care team have an important role in the management of patients with OUD, including those patients undergoing possible precipitated withdrawal.