Clinical trial NCT05819476: Boosting Open-Label Placebo Effects in Acute Induced Pain in Healthy Adults
Official title: Boosting Open-Label Placebo Effects in Acute Induced Pain in Healthy Adults
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Acute Pain
Keywords: Open-Label Placebo (OLP)
OLP analgesia
acute pain
hyperalgesia
allodynia
Lead sponsor: University Hospital, Basel, Switzerland
Sponsor class: OTHER
First posted: 2023-04-19
Enrollment: 141
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: The first part of this study is designed as a confirmatory, randomized, two-arm, assessor-blinded cross-over trial in a monocentric setup at the University Hospital of Basel.

The second part is designed as a proof-of-concept, randomized, controlled, three-arm trial in a monocentric setup at the University Hospital of Basel.
Primary purpose: OTHER

Brief summary: This study is to investigate the effect of open-label placebo (OLP) application on acute pain in an experimental model of acute pain (simulating wound pain: this installation will apply monophasic, rectangular electrical pulses of 0.5ms duration with alternating polarity at 2 Hz frequency. The current will be increased to target a pain rating of 6 of 10 on the NRS (0 = no pain, 10 = worst imaginable pain). Three further adjustments in current will be made every 5 minutes for the next 15 minutes to compensate for habituation. This final current will be kept constant until the end of the particular experiment).

In Part 1 duration of OLP analgesia will be examined, and onset and size of the effect will be reevaluated.

In Part 2 of this study outcomes between subjects receiving one OLP injection, subjects receiving one repetition of the injection on a fixed time point and subjects receiving one repetition of the injection on-demand will be evaluated

Detailed description: Pain is highly prevalent in hospital settings. Standard systemic treatment for acute pain consists mainly of basic analgesia. The use of these drugs is often restricted due to their contraindications. Placebo is used nowadays to describe sham treatments and "inert" substances like sugar pills and saline injections. Placebos are proven to elicit clinically significant effects in various conditions, including pain. Ethical concerns about the use of deceptive placebos have prevented their implementation in clinical practice. A possibility to address this issue would be to prescribe placebos openly, that means, without deception. This randomized crossover study evaluates the efficacy of open-label placebo (OLP) in acute pain. Subjective pain ratings and areas of hyperalgesia and allodynia will be measured in a well-established experimental pain model (intradermal electrical stimulation model evoking pain: this installation will apply monophasic, rectangular electrical pulses of 0.5ms duration with alternating polarity at 2 Hz frequency. The current will be increased to target a pain rating of 6 of 10 on the NRS (0 = no pain, 10 = worst imaginable pain). Three further adjustments in current will be made every 5 minutes for the next 15 minutes to compensate for habituation. This final current will be kept constant until the end of the particular experiment) and analgesia elicited by OLP injections will be investigated.

In Part 1 duration of OLP analgesia will be examined, and onset and size of the effect will be reevaluated.

In Part 2 of this study outcomes between subjects receiving one OLP injection, subjects receiving one repetition of the injection on a fixed time point and subjects receiving one repetition of the injection on-demand will be evaluated (which leaves the last group a choice over when they would like to have the placebo "booster").

Eligibility criteria: Inclusion Criteria:

* Healthy volunteers (ASA Class I or II), aged 18 to 65 years
* BMI between 18 and 25kg/m2
* Able to understand the study and the NRS
* Able to give informed consent

Exclusion Criteria:

* Participation in a previous open-label placebo study; for Part 2, this includes Part 1 of this study
* Regular intake of medications or drugs potentially interfering with pain sensation (analgesics, opioids, antihistamines, calcium and potassium channel blockers, serotonin/ noradrenaline reuptake inhibitors, corticosteroids)
* Neuropathy
* Chronic pain
* Neuromuscular disease
* Dermatological disease (i.e. Atopic Dermatitis)
* Psychiatric disease
* Pregnancy / Lactation

Primary outcomes:
measure: Part 1: Change in Area under the Pain Curve (AUPC)
timeFrame: During three hours after administering an OLP
measure: Part 2: Change in Area under the Pain Curve (AUPC)
timeFrame: During three hours after administering an OLP
Secondary outcomes:
measure: Part 1 and 2: Change in subjective pain ratings on each measurement point using the numeric rating scale (NRS)
timeFrame: Up to 200 minutes after electrical pain stimulation
measure: Part 1 and 2: Change in Area under the Curve (AUC) of area of hyperalgesia
timeFrame: Up to 200 minutes after electrical pain stimulation
measure: Part 1 and 2: Change in Area under the Curve (AUC) of area of allodynia
timeFrame: Up to 200 minutes after electrical pain stimulation
Other outcomes:
Locations:
city: Basel
country: Switzerland
facility: University Hospital of Basel (USB); Department of Anaesthesiology
Study officials:
affiliation: Department of Anaesthesiology, University Hospital of Basel (USB)
name: Tobias Schneider, MD
role: PRINCIPAL_INVESTIGATOR
References: