Trial Outcomes & Findings for The Effect of Chronic Pain on Delay Discounting in Methadone Patients (NCT NCT04473950)
NCT ID: NCT04473950
Last Updated: 2025-03-26
Results Overview
Delay discounting is the relative preference for smaller sooner over larger later rewards, an aspect of impulsivity. Most individuals would prefer an immediate $100 over $100 delayed by 1 year. However, when faced with the choice between receiving $95 now versus $100 in 1 year, preferences for the delayed reward may increase. By assessing such choices across multiple delays, delay discounting quantifies the devaluation of rewards over time, which allows for an index of overall discounting rate (k). Delay Discounting of money rate has no units and values can go from 0-infinity. A larger discount rate indicates that a future reward is devalued more, and is associated with more impulsive behavior.
Recruitment status
TERMINATED
Study phase
PHASE1
Target enrollment
10 participants
Primary outcome timeframe
k will be calculated from the same series of discounting questions that will be asked once each session at approximately 30 minutes after study medication administration.
Results posted on
2025-03-26
Participant Flow
We began study recruitment in January 2020 (Q2) after IRB approval was received. The first study participant screening session was on January 21, 2020. UCSF halted all non-essential clinical research in March 2020 and we were unable to conduct research activities on a full 5 day a week schedule until one year later, with some periods during winter surges when we had to again shut down all research activities.
Participant milestones
| Measure |
Pain Group
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Overall Study
STARTED
|
6
|
4
|
|
Overall Study
Naloxone
|
6
|
4
|
|
Overall Study
Placebo
|
6
|
4
|
|
Overall Study
COMPLETED
|
6
|
4
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
The Effect of Chronic Pain on Delay Discounting in Methadone Patients
Baseline characteristics by cohort
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
Total
n=10 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
53.83 years
STANDARD_DEVIATION 10.98 • n=5 Participants
|
38.25 years
STANDARD_DEVIATION 7.46 • n=7 Participants
|
47.6 years
STANDARD_DEVIATION 12.26 • n=5 Participants
|
|
Sex: Female, Male
Female
|
2 Participants
n=5 Participants
|
3 Participants
n=7 Participants
|
5 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
4 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
5 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
2 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
4 Participants
n=5 Participants
|
4 Participants
n=7 Participants
|
8 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Asian
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
White
|
5 Participants
n=5 Participants
|
3 Participants
n=7 Participants
|
8 Participants
n=5 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
|
Region of Enrollment
United States
|
6 participants
n=5 Participants
|
4 participants
n=7 Participants
|
10 participants
n=5 Participants
|
PRIMARY outcome
Timeframe: k will be calculated from the same series of discounting questions that will be asked once each session at approximately 30 minutes after study medication administration.Delay discounting is the relative preference for smaller sooner over larger later rewards, an aspect of impulsivity. Most individuals would prefer an immediate $100 over $100 delayed by 1 year. However, when faced with the choice between receiving $95 now versus $100 in 1 year, preferences for the delayed reward may increase. By assessing such choices across multiple delays, delay discounting quantifies the devaluation of rewards over time, which allows for an index of overall discounting rate (k). Delay Discounting of money rate has no units and values can go from 0-infinity. A larger discount rate indicates that a future reward is devalued more, and is associated with more impulsive behavior.
Outcome measures
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Delay Discounting of Money Rate (k)
Naloxone Session
|
-1.65 k-value
Standard Deviation 1.17
|
-2.16 k-value
Standard Deviation 0.92
|
|
Delay Discounting of Money Rate (k)
Placebo Session
|
-1.91 k-value
Standard Deviation 0.56
|
-2.11 k-value
Standard Deviation 1.11
|
SECONDARY outcome
Timeframe: Peak Pain VAS will be the highest rating during each 2 hour study session.Population: There was missing data for one participant with chronic pain in the placebo session.
Current pain level rated on 0-100 VAS. This is the validated pain scale typically used by clinicians in an outpatient or inpatient clinical visit to represent current level of pain. Higher ratings indicate worse pain severity.
Outcome measures
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Study Session Peak Pain Visual Analog Scale (VAS)
Placebo
|
25.2 score on a scale
Standard Deviation 22.9
|
0 score on a scale
Standard Deviation 0
|
|
Study Session Peak Pain Visual Analog Scale (VAS)
Naloxone
|
28.2 score on a scale
Standard Deviation 25.4
|
0.25 score on a scale
Standard Deviation 0.5
|
SECONDARY outcome
Timeframe: Peak COWS rating will be the highest rating during each 2 hour study session.The COWS is an 11-item validated clinician administered scale that quantifies level of opioid withdrawal. The range of scores is 0-48, with higher scores indicating greater withdrawal severity. The peak COWS rating will be the highest measurement in the session after study drug administration.
Outcome measures
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Peak Clinical Opiate Withdrawal Scale (COWS) Rating
Placebo
|
1.8 score on a scale
Standard Deviation 0.98
|
2.75 score on a scale
Standard Deviation 0.5
|
|
Peak Clinical Opiate Withdrawal Scale (COWS) Rating
Naloxone
|
2.5 score on a scale
Standard Deviation 2.6
|
3 score on a scale
Standard Deviation 2.4
|
SECONDARY outcome
Timeframe: Peak SOWS rating will be the highest rating during each 2 hour study session.The SOWS is a 16 item validated self-administered scale for grading opioid withdrawal symptoms. The range of scores is 0-64, with higher scores indicating greater withdrawal severity. The peak SOWS rating will be the highest measurement in the session after study drug administration.
Outcome measures
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Peak Subjective Opiate Withdrawal Scale (SOWS) Rating
Placebo
|
3.2 score on a scale
Standard Deviation 2.6
|
2.8 score on a scale
Standard Deviation 2.1
|
|
Peak Subjective Opiate Withdrawal Scale (SOWS) Rating
Naloxone
|
2.7 score on a scale
Standard Deviation 2.9
|
3.8 score on a scale
Standard Deviation 2.1
|
SECONDARY outcome
Timeframe: Peak increase from baseline pupil diameter will be the largest increase from baseline pupil diameter measured during each 2 hour study session.Pupil diameter (mm) will be measured via digital pupillometer in standard room lighting at baseline and then throughout the study session after study drug administration. The peak increase from baseline value will be the largest increase from baseline pupil diameter measured after study drug administration.
Outcome measures
| Measure |
Pain Group
n=6 Participants
Patients with chronic pain who are maintained on methadone for opioid use disorder
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
No Pain Group
n=4 Participants
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|
|
Peak Increase From Baseline Pupil Diameter
Placebo
|
0.06 millimeters
Standard Deviation 0.08
|
0.03 millimeters
Standard Deviation 0.07
|
|
Peak Increase From Baseline Pupil Diameter
Naloxone
|
0.31 millimeters
Standard Deviation 0.44
|
0.07 millimeters
Standard Deviation 0.09
|
Adverse Events
Pain Group, Placebo Session
Serious events: 0 serious events
Other events: 1 other events
Deaths: 0 deaths
Pain Group, Naloxone Session
Serious events: 0 serious events
Other events: 2 other events
Deaths: 0 deaths
No Pain Group, Placebo Session
Serious events: 0 serious events
Other events: 1 other events
Deaths: 0 deaths
No Pain Group, Naloxone Session
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Pain Group, Placebo Session
n=6 participants at risk
Patients with chronic pain who are maintained on methadone for opioid use disorder. Placebo: An IM injection of 0.9% normal saline will be given.
|
Pain Group, Naloxone Session
n=6 participants at risk
Patients with chronic pain who are maintained on methadone for opioid use disorder. Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
|
No Pain Group, Placebo Session
n=4 participants at risk
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain. Naloxone Hydrochloride: An intramuscular (IM) injection of naloxone will be given.
|
No Pain Group, Naloxone Session
n=4 participants at risk
Patients who are maintained on methadone for opioid use disorder but who do not have chronic pain.
Placebo: An IM injection of 0.9% normal saline will be given.
|
|---|---|---|---|---|
|
Nervous system disorders
Dizziness
|
0.00%
0/6 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
16.7%
1/6 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
|
Eye disorders
Tunnel Vision
|
0.00%
0/6 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
16.7%
1/6 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
|
Nervous system disorders
Paranoia
|
0.00%
0/6 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
16.7%
1/6 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
|
Eye disorders
Eye Irritation
|
0.00%
0/6 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/6 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
25.0%
1/4 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
|
Nervous system disorders
Somnolence
|
16.7%
1/6 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
16.7%
1/6 • Number of events 1 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
0.00%
0/4 • 2 sessions were held approximately 1 week apart. Adverse events were collected after receiving the first injection of study medication until 24 hours after the last session. This was approximately 8 days for participants assuming sessions were held one week apart.
|
Additional Information
David Andrew Tompkins, MD, MHS
University of California, San Francisco
Phone: 628-206-3645
Email: [email protected]
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place