Efficacy of Spinal Oxytocin in Healthy Volunteers

Efficacy of Intrathecal Oxytocin in Human Volunteers

The purpose of this study is to determine the effect of intrathecal oxytocin on areas and intensity of hyperalgesia and allodynia induced by topical capsaicin.

Study Overview

• Status: Terminated
• Conditions: Healthy Volunteer Study
• Intervention / Treatment: Drug: Oxytocin 15 mcg; Drug: Oxytocin 150 mcg; Drug: Placebo

Detailed Description

Purpose: There is a strong experimental basis to support the study of oxytocin by the spinal route for analgesia in humans. Oxytocin containing cells in the dorsal parvocellular division of the paraventricular nucleus (PVN) project to the spinal cord (1). Noxious stimulation activates these cells via the A1 noradrenergic relay in the pons (2) and produces analgesia by spinal release of oxytocin, since intrathecal injection of an oxytocin receptor antagonist worsens pain behaviors from peripheral inflammation (3). Direct electrical stimulation of the PVN reduces dorsal horn neuronal responses to noxious stimulation, and this is blocked by administration of sequestering antibody for oxytocin (4). Similarly, direct electrical stimulation of the PVN reduces behavioral sensitivity in a model of chronic neuropathic pain, and this effect is blocked by an oxytocin receptor antagonist (5). Intrathecal injection of oxytocin in normal rats reduces dorsal horn neuronal responses to noxious stimuli (6) as well as behavioral responses to noxious thermal (3), mechanical (3), and chemical (7) stimuli. Finally, intrathecal injection of oxytocin in rat models of chronic pain also reduces dorsal horn neuronal responses to sensory stimulation (6) as well as behavioral responses to thermal (5) and mechanical (7) stimuli.

Rationale: We anticipate that oxytocin will be effective after spinal injection in humans against chemical induced hypersensitivity states.

Objectives: Determine the effect of intrathecal oxytocin on areas and intensity of hyperalgesia and allodynia induced by topical capsaicin.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Winston-Salem, North Carolina, United States, 27157
      • Wake Forest Baptist Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 59 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• healthy
• weight < 240 pounds
• American Society of Anesthesiology Category 1 or 2

Exclusion Criteria:

• allergy to oxytocin or lidocaine
• allergy to chilli peppers
• Females: active gynecological disease such as uterine fibroids or ongoing bleeding
• Pregnancy or currently breastfeeding
• Females that have delivered a baby within 2 years of study
• Taking prescription medications (exception: oral birth control medication)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Oxytocin 15 mcg; Oxytocin 15 mcg injected spinally	Drug: Oxytocin 15 mcg; Oxytocin 15 mcg will be administered spinally
Experimental: Oxytocin 150 mcg; Oxytocin 150 mcg injected spinally	Drug: Oxytocin 150 mcg; Oxytocin 150 mcg will be administered spinally
Active Comparator: Placebo; Preservative free normal saline injected spinally	Drug: Placebo; placebo will be administered spinally

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hyperalgesia	The area of hyperalgesia after the first skin heating following topical capsaicin.	105 minutes after study drug injection

Collaborators and Investigators

• Sponsor: Wake Forest University Health Sciences
• Investigators: Principal Investigator: James C Eisenach, MD, Wake Forest University Health Sciences

Study record dates

Study Major Dates

• Study Start: January 2, 2014
• Primary Completion (Actual): October 10, 2022
• Study Completion (Actual): October 10, 2022

Study Registration Dates

• First Submitted: November 21, 2013
• First Submitted That Met QC Criteria: November 21, 2013
• First Posted (Estimated): November 27, 2013

Study Record Updates

• Last Update Posted (Actual): September 14, 2023
• Last Update Submitted That Met QC Criteria: August 31, 2023
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Reproductive Control Agents; Oxytocics; Oxytocin
• Other Study ID Numbers: IRB00025901

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No