Morphine or Ketamine for Analgesia

Pain is common in children presenting to the emergency department but is frequently undertreated, leading to both short- and long-term consequences. Morphine is the standard treatment for children with moderate to severe acute pain, but its use is associated with serious side effects and caregiver and clinician concerns related to opioid administration. The investigators aim to determine if sub-dissociative ketamine is non-inferior to morphine for treating acute pain and a preferable alternative for treating acute pain in children because of its more favorable side effect profile and potential long-term benefits related to pain-related function, analgesic use/misuse, and mental and behavioral health outcomes.

Inclusion Criteria: 1. Abdominal pain or isolated long-bone extremity fracture (suspected or proven) 2. Self-reported pain score of ≥ 6/10 3. Requires IV morphine for analgesia as determined by the treating physician Exclusion Criteria: 1. Weight \> 82.4 kg 2. Known allergy/contraindication to morphine or ketamine 3. Antecedent receipt of ketamine related to presenting complaint 4. Inability to use self-report measures of pain or questionnaires 5. Chronic disease associated with pain 6. Chronic pain condition requiring use of opioids as outpatient 7. Hemodynamic instability or critical illness per treating physician 8. Altered mental state (e.g., GCS , 14 or clinical intoxication) 9. Known history of schizophrenia, liver or kidney problems, or osteogenesis imperfecta 10. Concern for open fracture, neurovascular compromise, or compartment syndrome 11. Injuries in addition to the extremity injury (e.g., head, neck, abdomen) 12. Known or reported pregnancy 13. Does not speak English or Spanish 14. Patient previously enrolled in this study 15. Wards of state, foster children, or children in custody