The purpose of this study is to test whether perioperative intravenous (IV) oxytocin compared to placebo results in faster recovery in disability as measured by daily steps over 56 days after Total Hip Arthroplasty (THA).

This is a single center, NIH funded clinical study at Atrium Health Wake Forest Baptist Medical Center. The investigators will utilize a triple-masked, parallel group, randomized design to compare intravenous (IV) oxytocin to placebo to determine IV oxytocin's actions on speed of recovery from physical disability and postoperative pain after Total Hip Arthroplasty (THA).

Inclusion Criteria:

• Male or female > 18 and ≤75 years of age
• Scheduled for unilateral, primary total hip arthroplasty surgery
• Generally in good health as determined by the Principal Investigator based on prior medical history, and as assessed to be American Society of Anesthesiologists physical status 1, 2, or 3
• Willing to perform the study procedures
• Able to read and write English and have a stable residence.

Exclusion Criteria:

• Hypersensitivity to any ingredient in Pitocin® (marketed preparation of oxytocin for parenteral injection)
• Latex allergy
• Any disease, diagnosis, or condition (medical or surgical) that, in the opinion of the Principal Investigator, would place the participant at increased risk (e.g., active gynecologic disease in which increased tone would be detrimental such as uterine fibroids with ongoing bleeding)
• Women who are pregnant, are currently nursing or lactating, or have been pregnant within 2 years
• Current or history of ventricular tachycardia, atrial fibrillation or prolonged QT interval.
• Past or current history of hyponatremia or at risk for hyponatremia; anyone taking thiazide diuretics, loop diuretics, combination diuretics, lithium, carbamazepine, enalapril, ramipril, celecoxib, temazepam, gliclazide, glimepiride, glibenclamide, glipizide, omeprazole, pantoprazole, desmopressin, Selective Serotonin Reuptake Inhibitors (SSRI's), Monoamine oxidase inhibitors (MAOIs), or the recreational drug ecstasy.
• Inability to complete questionnaires
• Litigation or workers compensation related to their joint surgery
• Taking > 100 mg morphine equivalents/day
• Suffering from a psychotic disorder or a recent psychiatric hospitalization