Low Back Pain
Conditions
Brief summary
Duloxetine has recently been shown to be effective in reducing the pain in chronic pain patients. Duloxetine is known to exert a central mechanism, however the precise human brain structures responsible for mediating its pain-relieving properties are not known. We will use functional magnetic resonance imaging (FMRI) to investigate the neural and functional correlates of pain.
Interventions
DRUGduloxetine
30-60mg of duloxetine daily
DRUGPlacebo
Placebo pill once daily
Sponsors
Stanford University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 60 Years
Healthy volunteers
No
Inclusion criteria
- Males aged 18-60 * Back Pain * Must be able to comply with study visit schedule and other study requirements * Capable of performing the experimental tasks
Exclusion criteria
- Contraindications for MRI examination (e.g., metallic implants such as pacemakers, surgical aneurysm clips, or known metal fragments embedded in the body) * Known hypersensitivity to duloxetine or any of the inactive ingredients * Uncontrolled narrow-angle glaucoma
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pain | 3 months | Brief Pain Inventory (BPI) scores were obtained at baseline, weeks 1, 2, 6, 7, 8, and 12, and a follow-up visit one week after completing the study. Responses are rated on a scale from 0-10, with 0 = no pain and 10 = pain as bad as you can imagine. Placebo and duloxetine pain scores calculated by averaging pain scores from each visit after baseline. Values were converted to percent change in pain: \[(baseline pain - end point pain)/baseline pain\] x 100. |
| Neural Correlates of Pain Relief | 3 months | Scores reflect the average connectivity strength of that region of interest to the rest of the cortex. There were no minimum or maximum values on this scale. Higher scores reflect stronger connectivity, and lower scores reflect less connectivity (all scores fell within -3 and 3). Subscales are averaged. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Placebo Then Duloxetine In the first 8-week treatment period, participants received placebo to match duloxetine for 8 weeks. Following a -week washout period, in the second 8-week treatment period, participants received duloxetine starting at 30 mg (1 week), with titer up to 60 mg (2 weeks), maintained dose (4 weeks), and titer back down to 30 mg (1 week). | 7 |
| Duloxetine Then Placebo In the first 8-week treatment period, participants received duloxetine starting at 30 mg (1 week), with titer up to 60 mg (2 weeks), maintained dose (4 weeks), and titer back down to 30 mg (1 week). Following a -week washout period, in the second 8-week treatment period, participants received placebo to match duloxetine for 8 weeks. | 7 |
| Total | 14 |
Baseline characteristics
| Characteristic | Duloxetine Then Placebo | Placebo Then Duloxetine | 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 | 7 Participants | 7 Participants | 14 Participants |
| Age, Continuous | 42.86 years STANDARD_DEVIATION 12.56 | 31 years STANDARD_DEVIATION 11.36 | 36.93 years STANDARD_DEVIATION 13.05 |
| Region of Enrollment United States | 7 participants | 7 participants | 14 participants |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 7 Participants | 7 Participants | 14 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 14 |
| other Total, other adverse events | 0 / 14 |
| serious Total, serious adverse events | 0 / 14 |
Outcome results
Primary
Neural Correlates of Pain Relief
Scores reflect the average connectivity strength of that region of interest to the rest of the cortex. There were no minimum or maximum values on this scale. Higher scores reflect stronger connectivity, and lower scores reflect less connectivity (all scores fell within -3 and 3). Subscales are averaged.
Time frame: 3 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo - Sugar Pill | Neural Correlates of Pain Relief | Ventral Default Mode Networks | 0.521 Units on a scale | Standard Deviation 0.346 |
| Placebo - Sugar Pill | Neural Correlates of Pain Relief | Dorsal Default Mode Networks | 0.485 Units on a scale | Standard Deviation 0.277 |
| Duloxetine | Neural Correlates of Pain Relief | Ventral Default Mode Networks | 0.466 Units on a scale | Standard Deviation 0.279 |
| Duloxetine | Neural Correlates of Pain Relief | Dorsal Default Mode Networks | 0.492 Units on a scale | Standard Deviation 0.203 |
| Duloxetine | Neural Correlates of Pain Relief | Ventral Default Mode Networks | 0.468 Units on a scale | Standard Deviation 0.443 |
| Duloxetine | Neural Correlates of Pain Relief | Dorsal Default Mode Networks | 0.469 Units on a scale | Standard Deviation 0.315 |
Primary
Pain
Brief Pain Inventory (BPI) scores were obtained at baseline, weeks 1, 2, 6, 7, 8, and 12, and a follow-up visit one week after completing the study. Responses are rated on a scale from 0-10, with 0 = no pain and 10 = pain as bad as you can imagine. Placebo and duloxetine pain scores calculated by averaging pain scores from each visit after baseline. Values were converted to percent change in pain: \[(baseline pain - end point pain)/baseline pain\] x 100.
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Placebo - Sugar Pill | Pain | -1 Percentage change from baseline to end | Standard Deviation 76 |
| Duloxetine | Pain | -43 Percentage change from baseline to end | Standard Deviation 32 |