Dose Ranging Study of Intravenous Oxytocin for Analgesia to Heat Pain

Phase 2

Completed

Conditions: Healthy Volunteer Study

Interventions: Drug: Low dose oxytocin
Drug: High dose oxytocin

Registration Number: NCT05179421

Lead Sponsor: Wake Forest University Health Sciences

Brief Summary: This is a study of participants that will receive intravenous (IV) infusions of oxytocin (naturally occurring hormone that is made by the brain).

In this study healthy participants will be recruited for the study. There will be 3 study related visits: 1) screening and informed consent 2) study medication infusions and thermal heat testing 3) study medication infusions and thermal heat testing. During study visits 2 and 3 an IV catheter will be placed and a dose of oxytocin or placebo (inactive solution) will be given over a 10 minute period; 1 hour after the first infusion, a second 10 minute infusion of oxytocin will be administered.

Investigators will perform some tests to evaluate how oxytocin changes perceptions of the skin. Investigators will study a painful perception by placing a probe on the skin of the side of lower leg and heating it up to 113-117 degrees Fahrenheit (F) (45-47 degrees Celsius (C)) for 5 minutes. Each participant will score any pain that is experienced on a 0 to 10 scale for each minute during the heating period. Most people find that pain rises during the 5 minutes, but remains mild; usually less than 5 on the 0 to 10 pain scale. The temperature of the 5 minute heating will be determined according to the participants pain rating during the screening visit.

The primary objective of the study is to determine the dose response of IV oxytocin for analgesia (pain relief) to experimental heat pain.

Detailed Description: Equal numbers of adult men and women; ages 18-75 will be recruited. Participants will report to the research unit for three visits, 1) screening and informed consent 2) study medication infusions and thermal heat testing 3) study medication infusions and thermal heat testing separated by at least 72 hours.

For study infusion visits, study participants will come to the Clinical Research Unit and one intravenous (IV) catheter will be inserted in the forearm for oxytocin infusions. Participants in this study will receive a dose of oxytocin or placebo at a steady rate for 10 minutes; one hour later, a second dose of oxytocin will be administered during one visit. During the second study infusion visit, a lower dose of oxytocin will be given by a 10-minute IV infusion and one hour later a second infusion of oxytocin at a higher dose will be given. On one study day the doses will by 0 and 1.3 micrograms (µg) and on the other study day the doses will be 0.3 and 7 µg oxytocin. The order of study days will be randomized and double-blinded. As a result, each participant will receive oxytocin doses of 0, 0.3, 1.3, and 7 µg in this double blind design.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 25

Inclusion Criteria

Male or female > 18 and < 75 years of age, Body Mass Index (BMI) <40.
Generally in good health as determined by the Principal Investigator based on prior medical history, American Society of Anesthesiologists physical status 1, 2, or 3.
For healthy volunteers, normal blood pressure (systolic 90-140 mmHg; diastolic 50-90 mmHg) resting heart rate 45-100 beats per minute) without medication. For knee arthritis subjects, normal blood pressure or, for those with hypertension, pressure controlled with anti-hypertensives and with a resting heart rate 45-100 beats per minute.
Female subjects of child-bearing potential and those < 1 year post-menopausal, must be practicing highly effective methods of birth control such as hormonal methods (e.g., combined oral, implantable, injectable, or transdermal contraceptives), double barrier methods (e.g., condoms, sponge, diaphragm, or vaginal ring plus spermicidal jellies or cream), or total abstinence from heterosexual intercourse for a minimum of 1 full cycle before study drug administration.

Exclusion Criteria

Hypersensitivity, allergy, or significant reaction to any ingredient of Pitocin®
Any disease, diagnosis, or condition (medical or surgical) that, in the opinion of the Principal Investigator, would place the subject at increased risk (active gynecologic disease in which increased tone would be detrimental e.g., uterine fibroids with ongoing bleeding), compromise the subject's compliance with study procedures, or compromise the quality of the data
Women who are pregnant (positive result for serum pregnancy test at screening visit), women who are currently nursing or lactating, women that have been pregnant within 2 years
Subjects with neuropathy, chronic pain, diabetes mellitus, or taking benzodiazepines or pain medications on a daily basis.
Subjects with current or history of ventricular tachycardia, atrial fibrillation or prolonged QT interval.
Subjects with 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, SSRI's, MAOI, or the recreational drug ecstasy.
Subjects with a known latex allergy.
Subjects with a pain score rating of 1 or less during the initial training session to a 5 minute heating of 45°C- 47 °C to the lower calf.

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
First infusion day low dose oxytocin, Second infusion day high dose oxytocin	Low dose oxytocin	On the first oxytocin study day, participants will receive a 10 minute IV infusion of saline then one hour later will receive a 10 minute infusion of oxytocin 1.3 micrograms. On the second study day they will receive a 10 minute IV infusion of oxytocin 0.3 micrograms then one hour later will receive a 10 minute infusion of oxytocin 7 micrograms.
First infusion day low dose oxytocin, Second infusion day high dose oxytocin	High dose oxytocin	On the first oxytocin study day, participants will receive a 10 minute IV infusion of saline then one hour later will receive a 10 minute infusion of oxytocin 1.3 micrograms. On the second study day they will receive a 10 minute IV infusion of oxytocin 0.3 micrograms then one hour later will receive a 10 minute infusion of oxytocin 7 micrograms.
First infusion day high dose oxytocin, Second infusion day low dose oxytocin	Low dose oxytocin	On the first oxytocin study day, participants will receive a 10 minute IV infusion of oxytocin 0.3 micrograms then one hour later will receive a 10 minute infusion of oxytocin 7 micrograms. On the second study day they will receive a 10 minute IV infusion of saline then one hour later will receive a 10 minute infusion of oxytocin 1.3 micrograms.
First infusion day high dose oxytocin, Second infusion day low dose oxytocin	High dose oxytocin	On the first oxytocin study day, participants will receive a 10 minute IV infusion of oxytocin 0.3 micrograms then one hour later will receive a 10 minute infusion of oxytocin 7 micrograms. On the second study day they will receive a 10 minute IV infusion of saline then one hour later will receive a 10 minute infusion of oxytocin 1.3 micrograms.

Primary Outcome Measures

Name	Time	Method
Dose Response of Intravenous Oxytocin on Sustained Heat Pain	45 min after the end of each study drug infusion	Pain intensity was reported by the subject at the end of the 5 minute heating of the skin to 45 - 47 degrees C, using a verbal pain scale 0-10. 0 is equivalent to NO PAIN and 10 is equivalent to THE WORST PAIN IMAGINABLE. Heating temperature was determined for each individual according to pain rating during screening visit. Pain scores obtained at 15, 30, and 45 minutes after the end of each 10 minute infusion were averaged for each individual and analyzed as th

Secondary Outcome Measures