Ketamine for Pain in the Emergency Department

Inclusion Criteria: * Acute pain (including acute on chronic pain) * Pain score of moderate to severe (\> 4/10) on the Numerical Rating Scale * Provider determines the patient requires intravenous ketamine for analgesia Exclusion Criteria: * History of hypersensitivity to ketamine * Altered mental status * Psychiatric illness * Known history of renal or hepatic insufficiency * Acute head or eye injury * Suspected intracranial hypertension or mass * Headache as the chief complaint * Alcohol or drug abuse * Received an analgesic within the last four hours * History of congestive heart failure * History of aortic or brain aneurysm * Active Chest Pain * Porphyria * Active methadone treatment * Pregnant or breastfeeding * Signs of respiratory, hemodynamic, or neurologic compromise * Systolic blood pressure \< 90 mmHg or \> 180 mmHg * Heart rate \< 50 beats per minute or \> 150 beats per minute * Respiratory rate \< 10 breaths per minute or \> 30 breaths per minute * Glasgow Coma Score \< 15 * Previously received ketamine \< 0.3 mg/kg IV for acute pain in the emergency department