Pain
Conditions
Brief summary
The purpose of this study is to examine opioid and endocannabinoid mechanisms of exercise-induced analgesia in men and women.
Interventions
DRUGNaltrexone, then placebo
50 mg of naltrexone
DRUGPlacebo, then Naltrexone
sugar pill
Sponsors
University of Wisconsin, Madison
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Healthy men and women \-
Exclusion criteria
* current cardiac or other chronic diseases (e.g., cancer, diabetes, hypertension, kidney disease); routine use of prescriptive medications; history of vasovagal response to phlebotomy; an allergy to naltrexone; pregnancy; current smokers; current use of recreational drugs; history of substance abuse
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Time for Subject to Reach Pain Threshold | Baseline |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Naltrexone Then Placebo All participants completed both naltrexone and placebo conditions | 29 |
| Placebo Then Naltrxone | 29 |
| Total | 58 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| Overall Study | Withdrawal by Subject | 1 | 0 | 0 | 1 |
Baseline characteristics
| Characteristic | Placebo Then Naltrxone | Naltrexone Then Placebo | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 29 Participants | 29 Participants | 58 Participants |
| Age, Continuous | 21 years STANDARD_DEVIATION 3 | 21 years STANDARD_DEVIATION 3 | 21 years STANDARD_DEVIATION 3 |
| Region of Enrollment United States | 29 participants | 29 participants | 58 participants |
| Sex: Female, Male Female | 15 Participants | 14 Participants | 29 Participants |
| Sex: Female, Male Male | 14 Participants | 15 Participants | 29 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 60 |
| other Total, other adverse events | 0 / 60 |
| serious Total, serious adverse events | 0 / 60 |
Outcome results
Primary
Time for Subject to Reach Pain Threshold
Time frame: Baseline
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Men, Placebo | Time for Subject to Reach Pain Threshold | Pain threshold at baseline | 16.1 seconds | Standard Deviation 12.1 |
| Men, Placebo | Time for Subject to Reach Pain Threshold | Pain threshold post exercise | 28.8 seconds | Standard Deviation 27.6 |
| Women, Placebo | Time for Subject to Reach Pain Threshold | Pain threshold post exercise | 24.1 seconds | Standard Deviation 35.3 |
| Women, Placebo | Time for Subject to Reach Pain Threshold | Pain threshold at baseline | 16.0 seconds | Standard Deviation 24 |
| Men, Naltrexone | Time for Subject to Reach Pain Threshold | Pain threshold at baseline | 15.0 seconds | Standard Deviation 10 |
| Men, Naltrexone | Time for Subject to Reach Pain Threshold | Pain threshold post exercise | 28.4 seconds | Standard Deviation 26.6 |
| Females, Naltrexone | Time for Subject to Reach Pain Threshold | Pain threshold at baseline | 14.8 seconds | Standard Deviation 24 |
| Females, Naltrexone | Time for Subject to Reach Pain Threshold | Pain threshold post exercise | 22.5 seconds | Standard Deviation 30.1 |