Efficacy of Spinal Oxytocin in Healthy Volunteers

Wake Forest University (WFU)

Status and phase: Terminated; Phase 2

Conditions: Healthy Volunteer Study

Treatments: Drug: Placebo; Drug: Oxytocin 150 mcg; Drug: Oxytocin 15 mcg

Study type: Interventional

Funder types: Other

Identifiers

NCT01996605

IRB00025901

Details and patient eligibility

About

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.

Full 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.

Enrollment: 20 patients

Sex: All

Ages: 18 to 59 years old

Volunteers: Accepts Healthy Volunteers

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)

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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20 participants in 3 patient groups

Oxytocin 15 mcg

Experimental group

Description:

Oxytocin 15 mcg injected spinally

Treatment:

Drug: Oxytocin 15 mcg

Oxytocin 150 mcg

Experimental group

Description:

Oxytocin 150 mcg injected spinally

Treatment:

Drug: Oxytocin 150 mcg

Placebo

Active Comparator group

Description:

Preservative free normal saline injected spinally

Treatment:

Drug: Placebo