The Effect of Oxytocin on Placebo Analgesia: an Experimental Study in Healthy Volunteers

What Was Tested

The trial (not phased) is built around Oxytocin.

Placebo responses contribute to medical treatment outcome.

It had two arms (groups): oxytocin (experimental) and placebo (placebo comparator).

Application of intranasal oxytocin 40IE.

The registry classes the interventions as drug and other.

More on the Plan

The rationale to study the effects of oxytocin on placebo analgesia is based on previous studies showing that oxytocin fosters processes such as empathy, trust and social learning, which are key elements of the patient-physician relationship that is pivotal to placebo responses.

In this experimental mechanisms study the researchers used oxytocin as a tool to modulate these factors.

Placebo analgesia is induced verbal instruction.

Therefore two identically looking placebo ointments were applied to two sites of the participants' volar forearm.

Who Took Part

Enrollment: 80 actual participants took part.

It was open to men only aged from 18 years up to 40 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: Healthy volunteers, male and female. Agreeing to participate, verified by completion of informed consent.

The full record lists 3 inclusion and 7 exclusion criteria; among the exclusions: acute or chronic pain condition; use of any concomitant medication except contraceptives; currently pregnant (verified by urine pregnancy test) or lactating.

How the Study Was Run

It was run as a randomized, parallel-group and triple-blind study.

Random assignment meant chance, not the researchers, decided who got Oxytocin and who got the comparison, which limits bias.

Groups ran in parallel: each of the participants stayed in one arm throughout.

Neither the participants nor the staff measuring them knew who was on Oxytocin, so expectations could not easily colour the readings.

Those kept unaware of assignments: participant, investigator and outcomes assessor.

It started in 2012-01 with completion listed for 2012-09.

It ran at 1 site in Germany.

Its stated primary purpose is basic science.

What Was Measured

Researchers chose this as the main measure: Placebo analgesic responses (time frame: ~ 45 min after appliction of oxytocin or saline).

It also tracked 1 secondary outcome, for example pain rating on the control site.

What This Means in Plain Language

Put simply, this is a not phased, randomized trial of Oxytocin in 80 people.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Oxytocin compound page, all human trials.