Ondansetron, a commonly used anti-vomiting medication, may reduce the occurrence of vomiting associated with ketamine during procedural sedation in the pediatric emergency department.

Inclusion Criteria:

• age 1-21 years, ASA I or II, fracture of dislocation reduction

Exclusion Criteria:

• age < 1 year, ASA III or IV, hypertension, glaucoma, acute globe injury, increased intracranial pressure or central nervous system mass lesion, major psychiatric disorder, porphyria, previous adverse reaction to ketamine or ondansetron, parent, guardian or patient unwilling to provide informed consent.