Intravenous Oxytocin for Post Operative Pain After Minimally Invasive Hysterectomy

December 28, 2025 updated by: John J. Kowalczyk, MD, Brigham and Women's Hospital
This is a randomized, double-blinded, placebo-controlled trial to compare the effectiveness of IV oxytocin infusion to placebo on peri-operative opioid consumption and reducing post-operative pain following a minimally invasive hysterectomy under general anesthesia.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

152 women will be randomized into one of two arms; participants in the first arm (Intervention) will receive oxytocin infusion, 30 IU in 500 ml IV infusion at a rate of 5 IU/h (83.33 ml/h), the second arm (Control) will receive 0.9% normal saline 500 ml IV infusion at the same rate of 83.3 ml/h. The primary care team (anesthesia, surgery, and nursing), the research team, and the patient will all be blinded to the research arm.

The investigational research pharmacy will perform randomization; participants will be randomized in a 1:1 ratio to receive either Oxytocin or Placebo (0.9% normal saline). Randomization will be blinded to investigators to prevent bias and ensure balance in treatment arms throughout the study. Participants, surgeons, clinicians, and raters will be blinded with respect to treatment assignments. The investigational pharmacy will prepare the study drug based on the randomization assignment received.

The investigators will identify patients who have been scheduled for an elective, minimally invasive hysterectomy at Brigham and Women's Hospital by reviewing the operating room booking schedule.

Patients will be pre-screened for inclusion and exclusion criteria. Subsequently, they will be recruited for participation in this study by phone/ MGB Zoom and will be consented by electronic consent.

Once the patient is recruited and consented, they will be randomized for either the intervention group (oxytocin IV infusion) or the control group (0.9% normal saline IV infusion).

An email will be sent to those who consent with a link to the secure REDCap system containing a set of baseline questionnaires to assess relevant medical and surgical history, pre-operative pain, analgesic medication use, and psychosocial variables.

Both groups (intervention and control) will be treated pre-operatively with the following Early Recovery After Surgery (ERAS) medications, as per usual institutional practice:

  • acetaminophen 1,000 mg orally
  • celecoxib 400 mg orally The Investigational Research Pharmacy will be informed and prepare blinded infusions for perioperative administration (oxytocin or placebo).

The primary anesthesiology team will receive either the study medication or placebo in a 500 ml bag labeled as "Oxytocin Study Drug for IV infusion".

A recommended "Intra-Operative Analgesia Management" algorithm will be given to the primary anesthetic team. The recommended algorithm for intra-operative analgesia management will include the following:

  • Fentanyl 100 mcg IV for induction.
  • Dexamethasone 8 mg IV after induction but prior to skin incision.
  • Small, titrated doses of Hydromorphone IV boluses (0.2-0.4 mg) during the operation and before emergence, according to primary team judgment.
  • Ketorolac 30 mg IV prior to skin closure, unless otherwise contraindicated.
  • Avoidance of other multimodal analgesic agents not included in this protocol to limit confounders.

The infusion will be started after the skin incision and will continue until the infusion is completed or the post-anesthesia care unit (PACU) criteria are met, whichever occurs first.

Other aspects of each patient's routine clinical care will continue as per standard care at the attending physician's discretion under whom the patient is admitted, regardless of treatment arm status.

In the PACU, a brief postoperative pain questionnaire will be performed, including the Surgical Pain Scales (SPS).

The SPS is a validated scale consisting of 4 items that measure pain at rest, during normal activities, and during work/exercise and quantify the unpleasantness of worst pain. This scale has been validated in a number of different types of postoperative pain, including women after gynecologic surgery.

Vital signs, numeric rating scale (NRS) pain scores, and opioid consumption in PACU will be collected from the patient's medical record.

Patients whose surgery was converted to open, estimated blood loss (EBL) >500 ml, or any other surgical complication that necessitates hospitalization will be excluded from the trial.

For secondary outcomes, including total opioid consumption in 24, 48, and 72 hours and pain scores at postoperative day (POD)1, 2, and 3, an online survey will be done at POD1, 2, and 3, and follow-up will continue until 3 months post-op.

Study Type

Interventional

Enrollment (Estimated)

152

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Recruiting
        • Brigham and Women's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Ages 18-65 years old
  • ASA category 1-3
  • Scheduled to undergo minimally invasive hysterectomy
  • No documented allergy to oxytocin

Exclusion Criteria:

  • American Society of Anesthesiologists (ASA) group 4 or greater
  • Age >65 years old
  • Additional surgical procedures including but not limited to minor laparotomy, omentectomy, cystectomy, vaginectomy, and/or ablation of endometriosis.
  • Active opioid prescription of the equivalent of oxycodone >10 mg /day
  • Opioid use disorder, including patients in treatment receiving naltrexone or Suboxone (Buprenorphine-naloxone)
  • Allergies to any study medication: acetaminophen, celecoxib, ketorolac, fentanyl, hydromorphone, or oxycodone.
  • Epidural/Regional anesthesia for intra-operative or post-operative pain.
  • Inability to understand the questionnaires
  • Intra-operative and post-operative exclusion: Procedure converted to open or extension of primary surgery, Intra-operative EBL >500 ml., Placement of epidural catheter or regional anesthesia at PACU for pain management, Hospitalization of the patient due to surgical or anesthetic complications

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Medication
one group will receive Oxytocin infusion: 30 IU in 500 ml of 0.9% normal saline .
Drug: Oxytocin
Intravenous Oxytocin infusion
Other Names:
  • Pitocin
Placebo Comparator: Placebo
one group will receive 500 ml of 0.9% normal saline
Drug: Placebo
0.9% Saline
Other Names:
  • 0.9% Saline
  • Normal Saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Post-operative pain
Time Frame: Between 2-4 hours after surgery completion (in the PACU)
Assess the impact of a perioperative infusion of oxytocin on postoperative pain, the average patient pain scores measured as a mean Brief Pain Inventory in PACU after laparoscopic hysterectomy in treated and untreated groups will be compared
Between 2-4 hours after surgery completion (in the PACU)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Perioperative opioid consumption
Time Frame: From start of infusion until approximately 6 hour mark (infusion completion)
Compare the impact of a perioperative infusion of oxytocin on perioperative opioid consumption, by comparing the average in perioperative opioids (OMEs)
From start of infusion until approximately 6 hour mark (infusion completion)
POD1 Opioid consumption
Time Frame: In the first 24 hours after surgery
Compare the impact of a perioperative infusion of oxytocin on perioperative opioid consumption, by comparing the average in perioperative opioids (OMEs)
In the first 24 hours after surgery
POD2 Opioid consumption
Time Frame: From 24-48 hours after surgery
Compare the impact of a perioperative infusion of oxytocin on perioperative opioid consumption, by comparing the average in perioperative opioids (OMEs)
From 24-48 hours after surgery
POD3 Opioid consumption
Time Frame: From 48-72 hours after surgery
Compare the impact of a perioperative infusion of oxytocin on perioperative opioid consumption, by comparing the average in perioperative opioids (OMEs)
From 48-72 hours after surgery
PACU satisfaction scores
Time Frame: Between 2-4 hours after surgery completion (in the PACU)
Compare patient postoperative satisfaction scores on an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable) between groups
Between 2-4 hours after surgery completion (in the PACU)
POD1 satisfaction scores
Time Frame: On Post-operative day 1
Compare patient postoperative satisfaction scores on an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable) between groups
On Post-operative day 1
POD2 satisfaction scores
Time Frame: On Post-operative day 2
Compare patient postoperative satisfaction scores on an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable) between groups
On Post-operative day 2
POD3 satisfaction scores
Time Frame: On Post-operative day 3
Compare patient postoperative satisfaction scores on an 11 -point Numerical Rating Scale between groups
On Post-operative day 3
PACU Post-operative pain
Time Frame: Between 2-4 hours after surgery completion (in the PACU)
Compare average patient pain scores measured as a mean Brief Pain Inventory (an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable)) in PACU after laparoscopic hysterectomy in treated and untreated groups
Between 2-4 hours after surgery completion (in the PACU)
POD1 Post-operative pain
Time Frame: On Post-operative day 1
Compare average patient pain scores measured as a mean Brief Pain Inventory (an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable)) on POD1 in treated and untreated groups
On Post-operative day 1
POD2 Post-operative pain
Time Frame: On Post-operative day 2
Compare average patient pain scores measured as a mean Brief Pain Inventory (an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable)) on POD2 in treated and untreated groups
On Post-operative day 2
POD3 Post-operative pain
Time Frame: On Post-operative day 3
Compare average patient pain scores measured as a mean Brief Pain Inventory (an 11 -point Numerical Rating Scale (with 0 being no pain and 10 being worst pain imaginable)) on POD3 in treated and untreated groups
On Post-operative day 3
Intraoperative hypotension (# of episodes of MAP <60 mmHg)
Time Frame: Through surgery completion, an average of 2 hours (From start of infusion to completion end of time in the operating room)
Assess the impact of a perioperative infusion of oxytocin on hypotension
Through surgery completion, an average of 2 hours (From start of infusion to completion end of time in the operating room)
PACU hypotension (# of episodes of MAP <60 mmHg)
Time Frame: Between 0-4 hours after surgery completion (in the PACU)
Assess the impact of a perioperative infusion of oxytocin on hypotension
Between 0-4 hours after surgery completion (in the PACU)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Brigham and Women's Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2025

Primary Completion (Estimated)

July 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

June 23, 2024

First Submitted That Met QC Criteria

June 29, 2024

First Posted (Actual)

July 3, 2024

Study Record Updates

Last Update Posted (Actual)

December 30, 2025

Last Update Submitted That Met QC Criteria

December 28, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2024P001376

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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