Study on the Effect of a Beta Blocker on Increased Sensitivity to Pain in Humans Caused by Opioids

Study Overview
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Brief Summary
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This research study explores whether a beta-blocker (propranolol) can prevent a person from becoming more sensitive to pain after administration of an opioid (remifentanil). Beta blockers inhibit the sympathetic (fight or flight) response and are often used to treat angina and high blood pressure. In a previous study in human volunteers, the investigators demonstrated an increased sensitivity to pain after a 60-minute infusion of the opioid remifentanil. The goal of this study is to identify a possible inhibitor of this phenomenon.

Detailed Description
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Recent evidence suggests that opioid therapy may cause a biphasic response, i.e. initial pain relief followed paradoxically by a longer lasting hypersensitivity to pain. Recent genetic analysis in mice suggests that beta adrenergic receptor antagonists reduce opiate-induced hyperalgesia (OIH). The purpose of this study is to determine the analgesic and antihyperalgesic properties of the beta-blocker propranolol on remifentanil-induced hypersensitivity in humans. The investigators want to determine the analgesic and antihyperalgesic properties of the beta-blocker propranolol on remifentanil-induced hypersensitivity in humans. The investigators hope to learn whether the administration of beta-blocker propranolol will significantly diminish the hyperalgesic response after administration of an opioid. The primary outcome measure for this study is change in size (area) of secondary hyperalgesia after cessation of remifentanil infusion, a measure of OIH.

Official Title
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Effect of Beta Blockade on Opioid-Induced Hyperalgesia in Humans

Conditions
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Hyperalgesia

Intervention / Treatment
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* Drug: Propranolol
* Drug: Placebo to Match Propranolol
* Drug: Remifentanil


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy men, Age between 18 and 45 years Normal weight (according to the table provided by Metropolitan Life Insurance). Exclusion Criteria: Hypersensitivity to opioids or naloxone, History of addictive disease, Significant cardiac, respiratory, gastrointestinal, neurological, dermatological, and psychiatric diseases, Concurrent medication with an analgesic drug, Student and employees affiliated with our laboratory

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Propranolol, Then Placebo<br>Propranolol, a beta blocker, or placebo to match, will be given to test whether or not it could modulate the expression of remifentanil-induced postinfusion hyperalgesia (RPH) during two pain test including: mechanically evoked pain to map the size of the hyperalgesic skin region caused by electrical stimulation and heat pain. | Drug: Propranolol<br>* Propranolol administered intravenously, initially set to target plasma concentration of 5 ng/mL, titrated upward in 5 ng/mL intervals until a final concentration of 15 ng/mL is achieved.<br>* Other names: Innopran;Drug: Placebo to Match Propranolol<br> <br> Drug: Remifentanil<br>* Remifentanil administered intravenously at a plasma concentration of 3 ng/mL.<br>|
| Placebo Comparator: Placebo, Then Propranolol<br>Propranolol, a beta blocker, or placebo to match, will be given to test whether or not it could modulate the expression of remifentanil-induced postinfusion hyperalgesia (RPH) during two pain test including: mechanically evoked pain to map the size of the hyperalgesic skin region caused by electrical stimulation and heat pain. | Drug: Propranolol<br>* Propranolol administered intravenously, initially set to target plasma concentration of 5 ng/mL, titrated upward in 5 ng/mL intervals until a final concentration of 15 ng/mL is achieved.<br>* Other names: Innopran;Drug: Placebo to Match Propranolol<br> <br> Drug: Remifentanil<br>* Remifentanil administered intravenously at a plasma concentration of 3 ng/mL.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent Change From Baseline in Size (Area) of Secondary Hyperalgesia After Cessation of Remifentanil Infusion, a Measure of Opioid-induced Hyperalgesia (OIH). | A slightly modified version of a previously described model of secondary hyperalgesia was used. Two copper wires contained in a microdialysis catheter were inserted in parallel over a length of 5 mm into the dermis of the right volar forearm. The wires were connected to a constant current stimulator controlled by a pulse generator to deliver rectangular and monophasic pulses with a duration of 0.5 mg at 2 Hz. Over a period of 15 min, the current was increased by targeting a pain rating of 5 on an 11-point numeric rating scale (0 = no pain and 10 = maximum tolerable pain) until the hyperalgesic area surrounding the stimulation site was fully established. Once the area was established, the current was held constant. Percent change from baseline in size (area) of secondary hyperalgesia after cessation of remifentanil infusion was calculated per group. | Baseline; 15 min post remifentanil (REM) infusion; 60 min post REM infusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Objective Opioid Withdrawal Scale (OOWS) | OOWS: Is a 13-item instrument of documenting physically observable signs of withdrawal, which are rated as present (1) or absent (0) during the observation period. Maximum score = 13, minimum score = 0. Lower scores correspond to fewer symptoms. | Pretreatment [90 min prior to 60-min REM infusion]; 30 min prior to 60-min REM infusion; 15 and 40 min after start of 60-min REM infusion; 5, 15, and 75 minutes after finish of 60-min REM infusion) |