Trial Outcomes & Findings for A Research Study of an Investigational Drug ALO-02 (Oxycodone Hydrochloride and Naltrexone Hydrochloride) in Patients With Moderate to Severe Chronic Low Back Pain (NCT NCT01571362)

A Double-Blind, Placebo-Controlled, Randomized Withdrawal Study to Determine the Efficacy and Safety of ALO-02 Extended-Release Capsules in participants with Moderate to Severe Chronic Low Back Pain

A total of 410 participants were enrolled into the Open-Label Conversion and Titration Period and 281 participants were randomized into the Double-Blind Treatment Period, of which, 280 participants received study treatment.

A Research Study of an Investigational Drug ALO-02 (Oxycodone Hydrochloride and Naltrexone Hydrochloride) in Patients With Moderate to Severe Chronic Low Back Pain

Weekly average diary NRS-Pain scores were derived from the daily NRS-pain scale and calculated as the mean of the last 7 days. NRS-Pain scores based on an 11-point numerical rating scale from 0 (no pain) to 10 (worst possible pain). Higher scores indicate greater pain.

The RMDQ is a 24-item questionnaire designed to measure self-rated disability due to back pain. An individual participant's score can vary from 0 (no disability) to 24 (severe disability), with a lower score indicating better function; higher score indicating greater disability.

Measure represents the score at Randomization Baseline / score at Week 12 (or Early Termination) in PGA, a global evaluation that utilizes a 5-point Likert scale with a score of 1 being the best (Very Good) and a score of 5 being the worst (Very Poor).

Weekly average Diary NRS-pain scores are derived from the daily pain NRS and calculated as the mean of the last 7 days. Scores range from 0 equals (=) no pain to 10 = worst possible pain. Higher scores indicate greater pain.

Weekly average Diary NRS-pain scores are derived from the daily pain NRS and calculated as the mean of the last 7 days. Scores range from 0 = no pain to 10 = worst possible pain. Higher scores indicate greater pain.

Weekly average Diary NRS-pain scores are derived from the daily pain NRS and calculated as the mean of the last 7 days. Scores range from 0 = no pain to 10 = worst possible pain. Higher scores indicate greater pain.

Weekly average Diary NRS-pain scores are derived from the daily pain NRS and calculated as the mean of the last 7 days. Scores range from 0 = no pain to 10 = worst possible pain. Higher scores indicate greater pain.

BPI-sf is an 11-item self-report questionnaire that is designed to assess the severity and impact of pain on daily functions. BPI-sf includes 4 questions that assess pain intensity (worst, least, average, right now) and 7 questions that assess impact of pain on daily functions (general activity, mood, walking ability, normal work, relations with other people, sleep, enjoyment of life). BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain. Pain Severity Index is the mean of the 4 pain scores (worst, least, average, and right now) on the BPI-sf; range is 0=No pain to 10=Pain as bad as you can imagine; A higher score indicates greater pain severity. Pain Interference Index is the mean of the scores for the 7 items of the BPI-sf; range is 0=Does not interfere to 10=Completely interferes.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain. Pain Severity Index is the mean of the 4 pain scores (worst, least, average, and right now) on the BPI-sf; range is 0=No pain to 10=Pain as bad as you can imagine; A higher score indicates greater pain severity. Pain Interference Index is the mean of the scores for the 7 items of the BPI-sf; range is 0=Does not interfere to 10=Completely interferes.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

Pain Severity Index is the mean of the 4 pain scores (worst, least, average, and right now) on the BPI-sf; range is 0=No pain to 10=Pain as bad as you can imagine; a higher score indicates greater pain severity.

Pain Interference Index is the mean of the scores for the 7 items of the BPI-sf; range is 0=Does not interfere to 10=Completely interferes.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; Higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; higher scores indicate greater pain.

BPI-sf scores range from 0=No pain to 10=Pain as bad as you can imagine; higher scores indicate greater pain.

Pain Severity Index is the mean of the 4 pain scores (worst, least, average, and right now) on the BPI-sf; range is 0=No pain to 10=Pain as bad as you can imagine; a higher score indicates greater pain severity.

Pain Interference Index is the mean of the scores for the 7 items of the BPI-sf; range is 0=Does not interfere to 10=Completely interferes.

NRS-Pain scores based on an 11-point numerical rating scale from 0 (no pain) to 10 (worst possible pain). AUC was calculated using daily change from Baseline scores from Baseline until the last dose date in the Double-Blind Treatment Period. AUC was calculated for each participant using the linear trapezoidal method. Higher scores indicate greater pain.

The amount of acetaminophen administered for each treatment during the Double-Blind Treatment Period. Average daily use calculated as: total dose of rescue medication during Double-Blind Period divided by the number of days in Double-Blind Period.

The percentage of analgesic response is defined as: (rolling 7-day mean pain score during Titration Period - Screening Period pain intensity score) divided by Screening Period pain intensity score times100.

The percentage of analgesic response is defined as: (rolling 7-day mean pain score during Titration Period minus (-) Screening Period pain intensity score) divided by Screening Period pain intensity score times 100. An event was defined as a participant with 20, 30, 40, or 50% analgesic response from Screening. If there was no event for a participant, time to the event was considered censored at Day 42 of the Titration Period or before Day 42 of the Titration Period at the time of the last diary pain score. The survival duration begins on the date of first dose of study drug in the Titration Period and is calculated as the \[date of event or last diary pain score - date of first dose in Titration Period +1\].

The percentage of analgesic response is defined as: (rolling 7-day mean pain score during Titration Period - Screening Period pain intensity score) divided by Screening Period pain intensity score times 100.

The percentage of analgesic response is defined as: (rolling 7-day mean pain score during Titration Period - Screening Period pain intensity score) divided by Screening Period pain intensity score times 100. If there was no event for a participant, time to the event was considered censored at Day 42 of the Titration Period or before Day 42 of the Titration Period at the time of the last diary pain score. The survival duration begins on the date of first dose of study drug in the Titration Period and is calculated as the \[date of event or last diary pain score - date of first dose in Titration Period +1\].

The percentage of lost analgesic response is defined as: (rolling 7-day mean pain score during Double-Blind Period - Randomization Baseline pain intensity score) divided by Randomization Baseline pain intensity score times 100. If there was no event for a participant, time to the event was considered censored at Day 84 or before Day 84 at the time of the last diary pain score. The survival duration began on the date of first dose of study drug in the Double-Blind Period and was calculated as the \[date of event or last diary pain score - date of first dose in Double-Blind Treatment +1\].

The percentage of lost analgesic response was defined as: (rolling seven day mean pain score during Double-Blind Period - Randomization Baseline pain intensity score) divided by Randomization Baseline pain intensity score times 100. If there was no event for a participant, time to the event was considered censored at Day 84 or before Day 84 at the time of the last diary pain score. The survival duration began on the date of first dose of study drug in the Double-Blind Period and was calculated as the \[date of event or last diary pain score - date of first dose in Double-Blind Treatment +1\].

If there was no event for a participant, time to the event was considered censored at Day 84 or before Day 84 at time of treatment discontinuation for another reason.

If there was no event for a participant, time to the event was considered censored at Day 84 or before Day 84 at time of treatment discontinuation for another reason. The survival duration begins on the date of first dose in the Double-Blind period and is calculated as the \[date of event or discontinuation - date of first dose in Double-Blind Period +1\].

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. Higher scores indicate a worse outcome. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal.

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. Higher scores indicate a worse outcome. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal.

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. Higher scores indicate a worse outcome. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal.

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal. The scores are assessed as follows: 5-12 = mild; 13-24 = moderate; 25-36 = moderately severe; more than 36 = severe withdrawal.

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal. The scores are assessed as follows: 5-12 = mild; 13-24 = moderate; 25-36 = moderately severe; more than 36 = severe withdrawal.

The COWS contains 11 common opiate withdrawal signs or symptoms rated by the investigator or designee who, for each item, checked the number that best described the participant's signs or symptoms. The minimum total COWS score is 0, the maximum is 48. The summed score of the 11 items was used to assess a participant's level of opiate withdrawal. The scores are assessed as follows: 5-12 = mild; 13-24 = moderate; 25-36 = moderately severe; more than 36 = severe withdrawal.

The SOWS was completed daily by the participant during any of the 2-week tapers from study drug, as well as at each study visit, using an eDiary device, and contains 16 symptoms of opiate withdrawal rated by the participant (Scale of 0 to 4: 0 = not at all, 1 = a little, 2= moderately, 3= quite a bit, 4 = extremely). The sum of the scores on each item was the total SOWS score; the minimum possible SOWS score was 0, the maximum 64. Higher scores indicate a worse outcome.

The SOWS was completed daily by the participant during any of the 2-week tapers from study drug, as well as at each study visit, using an eDiary device, and contains 16 symptoms of opiate withdrawal rated by the participant (Scale of 0 to 4: 0 = not at all, 1 = a little, 2= moderately, 3= quite a bit, 4 = extremely). The sum of the scores on each item was the total SOWS score; the minimum possible SOWS score was 0, the maximum 64. Higher scores indicate a worse outcome.

The SOWS was completed daily by the participant during any of the 2-week tapers from study drug, as well as at each study visit, using an eDiary device, and contains 16 symptoms of opiate withdrawal rated by the participant (Scale of 0 to 4: 0 = not at all, 1 = a little, 2= moderately, 3= quite a bit, 4 = extremely). The sum of the scores on each item was the total SOWS score; the minimum possible SOWS score was 0, the maximum 64. Higher scores indicate a worse outcome.

RMDQ is a 24-item questionnaire designed to measure self-rated disability due to back pain the same day the questionnaire is completed. An individual participant's score could have ranged from 0 (no disability) to 24 (severe disability), with a lower score indicating better function; higher scores indicating greater disability.

RMDQ is a 24-item questionnaire designed to measure self-rated disability due to back pain the same day the questionnaire is completed. An individual participant's score could have ranged from 0 (no disability) to 24 (severe disability), with a lower score indicating better function.

RMDQ is a 24-item questionnaire designed to measure self-rated disability due to back pain the same day the questionnaire is completed. An individual participant's score could have ranged from 0 (no disability) to 24 (severe disability), with a lower score indicating better function.

RMDQ is a 24-item questionnaire designed to measure self-rated disability due to back pain the same day the questionnaire is completed. An individual participant's score could have ranged from 0 (no disability) to 24 (severe disability), with a lower score indicating better function.

Represents the score at Screening / score at Randomization Baseline in PGA of low back pain, a global evaluation that utilizes a 5-point Likert scale with a score of: 1 = very good, asymptomatic and no limitation of normal activities; 2 = good, mild symptoms, and no limitation of normal activities; 3 = fair, moderate symptoms and limitation to some normal activities; 4 = poor, severe symptoms and inability to carry out most normal activities; and a score of 5 = very poor; very severe symptoms, which were intolerable and inability to carry out all normal activities.

Represents the score at Screening / score at to end of the titration period in PGA of low back pain, a global evaluation that utilizes a 5-point Likert scale with a score of: 1 = very good, asymptomatic and no limitation of normal activities; 2 = good, mild symptoms, and no limitation of normal activities; 3 = fair, moderate symptoms and limitation to some normal activities; 4 = poor, severe symptoms and inability to carry out most normal activities; and a score of 5 = very poor; very severe symptoms, which were intolerable and inability to carry out all normal activities.

Represents the score at Randomization Baseline / score at Week 4 in PGA of low back pain, a global evaluation that utilizes a 5-point Likert scale with a score of: 1 = very good, asymptomatic and no limitation of normal activities; 2 = good, mild symptoms, and no limitation of normal activities; 3 = fair, moderate symptoms and limitation to some normal activities; 4 = poor, severe symptoms and inability to carry out most normal activities; and a score of 5 = very poor; very severe symptoms, which were intolerable and inability to carry out all normal activities.

Represents the score at Randomization Baseline / score at Week 8 in PGA of low back pain, a global evaluation that utilizes a 5-point Likert scale with a score of: 1 = very good, asymptomatic and no limitation of normal activities; 2 = good, mild symptoms, and no limitation of normal activities; 3 = fair, moderate symptoms and limitation to some normal activities; 4 = poor, severe symptoms and inability to carry out most normal activities; and a score of 5 = very poor; very severe symptoms, which were intolerable and inability to carry out all normal activities.

Satisfaction with treatment is a single-item self-rated instrument that measures the participant's overall satisfaction with the study drug during study participation on a 5-point likert scale ranging from 1 = Very dissatisfied to 5 = Very satisfied.

Satisfaction with treatment is a single-item self-rated instrument that measures the participant's overall satisfaction with the study drug during study participation on a 5-point likert scale ranging from 1 = Very dissatisfied to 5 = Very satisfied.

Participants used an electronic tablet at the center to rate their overall treatment satisfaction with study drug during study participation using a 5-point categorical scale (1 = very dissatisfied, 2 = dissatisfied, 3 = neither satisfied nor dissatisfied, 4 = satisfied, 5 = very satisfied).

SF-36v2 Health Survey is a self-administered questionnaire consisting of 36 questions, measuring 8 health aspects; physical functioning, role limitations due to physical problems, social functioning, bodily pain, mental health, role limitations due to emotional problems, vitality, and general health perception. These domains also combine to form two component summary scores evaluating mental health and physical health. The minimum score is 0 and the maximum score is 100. A higher scores indicates a better health state.

SF-36v2 Health Survey is a self-administered questionnaire consisting of 36 questions, measuring 8 health aspects; physical functioning, role limitations due to physical problems, social functioning, bodily pain, mental health, role limitations due to emotional problems, vitality, and general health perception. These domains also combine to form two component summary scores evaluating mental health and physical health. The minimum score is 0 and the maximum score is 100. A higher score indicate a better health state.

SF-36v2 Health Survey is a self-administered questionnaire consisting of 36 questions, measuring 8 health aspects; physical functioning, role limitations due to physical problems, social functioning, bodily pain, mental health, role limitations due to emotional problems, vitality, and general health perception. These domains also combine to form two component summary scores evaluating mental health and physical health. The minimum score is 0 and the maximum score is 100. A higher score indicate a better health state.

SF-36v2 Health Survey is a self-administered questionnaire consisting of 36 questions, measuring 8 health aspects; physical functioning, role limitations due to physical problems, social functioning, bodily pain, mental health, role limitations due to emotional problems, vitality, and general health perception. These domains also combine to form two component summary scores evaluating mental health and physical health. The minimum score is 0 and the maximum score is 100. A higher score indicate a better health state.

The EQ 5D Health Questionnaire is a self completion standardized instrument for use as a measure of health-related quality of life in terms of a single index value or utility score that consisted of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which was rated on a 3-point response scale (no problems/some or moderate problems/extreme problems), and the scores are combined to form a single index utility value between 0 and 1 with higher scores indicating better health.

The EQ-5D consists of a standard vertical 20cm visual analogue scale (EQ VAS), for recording a participant's rating for their current health related quality of life state; the scale went from 0 (worst imaginable health state) to 100 (best imaginable health state). Participants were asked to draw a line on the scale to indicate how good or bad your own health is today, in your opinion.

Self-completion standardized instrument for use as a measure of health-related quality of life in terms of a single index value or utility score that consisted of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which was rated on a 3-point response scale (no problems/some or moderate problems/extreme problems), and the scores are combined to form a single index utility value between 0 and 1 with higher scores indicating better health

The EQ-5D consists of a standard vertical 20cm visual analogue scale (EQ VAS), for recording a participant's rating for their current health related quality of life state; the scale went from 0 (worst imaginable health state) to 100 (best imaginable health state). Participants were asked to draw a line on the scale to indicate how good or bad your own health is today, in your opinion.

Self-completion standardized instrument for use as a measure of health-related quality of life in terms of a single index value or utility score that consisted of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which was rated on a 3-point response scale (no problems/some or moderate problems/extreme problems), and the scores are combined to form a single index utility value between 0 and 1 with higher scores indicating better health

The EQ-5D consists of a standard vertical 20cm visual analogue scale (EQ VAS), for recording a participant's rating for their current health related quality of life state; the scale went from 0 (worst imaginable health state) to 100 (best imaginable health state). Participants were asked to draw a line on the scale to indicate how good or bad your own health is today, in your opinion.

Self-completion standardized instrument for use as a measure of health-related quality of life in terms of a single index value or utility score that consisted of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which was rated on a 3-point response scale (no problems/some or moderate problems/extreme problems), and the scores are combined to form a single index utility value between 0 and 1 with higher scores indicating better health.

The EQ-5D consists of a standard vertical 20cm visual analogue scale (EQ VAS), for recording a participant's rating for their current health related quality of life state; the scale went from 0 (worst imaginable health state) to 100 (best imaginable health state). Participants were asked to draw a line on the scale to indicate how good or bad your own health is today, in your opinion.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment /absenteeism+presenteeism); and activity impairment. * work time missed - a measure of absenteeism, calculated as work time missed due to health problem (question 2) as a proportion of hours actually worked (question 4). * impairment while working - a measure of presenteeism, the degree to which health problem impacted work (question 5). * overall work impairment - a measure of overall work productivity loss due to health problem (absenteeism+presenteeism). * activity impairment - a measure of the degree to which health problem has affected ability to do regular activities other than work at a job (question 6). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. * work time missed - a measure of absenteeism, calculated as work time missed due to health problem (question 2) as a proportion of hours actually worked (question 4). * impairment while working - a measure of presenteeism, the degree to which health problem impacted work (question 5). * overall work impairment - a measure of overall work productivity loss due to health problem (absenteeism+presenteeism). * activity impairment - a measure of the degree to which health problem has affected ability to do regular activities other than work at a job (question 6). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % work time missed - a measure of absenteeism, calculated as work time missed due to health problem (question 2) as a proportion of hours actually worked (question 4). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % impairment while working - a measure of presenteeism, the degree to which health problem impacted work (question 5). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % overall work impairment - a measure of overall work productivity loss due to health problem (absenteeism+presenteeism). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % activity impairment - a measure of the degree to which health problem has affected ability to do regular activities other than work at a job (question 6). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % work time missed - a measure of absenteeism, calculated as work time missed due to health problem (question 2) as a proportion of hours actually worked (question 4). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % impairment while working - a measure of presenteeism, the degree to which health problem impacted work (question 5). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % overall work impairment - a measure of overall work productivity loss due to health problem (absenteeism+presenteeism). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

A self-reported measure of work productivity and impairment that yields 4 scores: Absenteeism (work time missed); Presenteeism (impairment at work/reduced on the job effectiveness); work productivity loss (overall work impairment/absenteeism+presenteeism); and activity impairment. % activity impairment - a measure of the degree to which health problem has affected ability to do regular activities other than work at a job (question 6). Each score is expressed as a percentage (0-100%) with higher numbers indicating greater impairment and less productivity.

Question 3a = In the past 4 weeks, have you been hospitalized due to chronic low back pain or any medication used for chronic low back pain?

Question 3a = In the past 4 weeks, have you been hospitalized due to chronic low back pain or any medication used for chronic low back pain?

Question 1: number of office visits directly related to chronic low back pain or any medication used for chronic low back pain.

Question 2: Money (dollars) spent out-of-pocket on physical treatments in the past 4 weeks to manage chronic low back pain

Question 3b: nights stayed in the hospital, if answer to Q3a was yes.

Question 1: number of office visits directly related to chronic low back pain or any medication used for chronic low back pain.

Question 2: Money (dollars) spent out-of-pocket on physical treatments in the past 4 weeks to manage chronic low back pain

Question 3b: nights stayed in the hospital, if answer to Q3a was yes.

Question 3a = In the past 4 weeks, have you been hospitalized due to chronic low back pain or any medication used for chronic low back pain?

Question 1: number of office visits directly related to chronic low back pain or any medication used for chronic low back pain

Question 2: money (dollars) spent out-of-pocket on physical treatments in the past 4 weeks to manage chronic low back pain.

Question 3b: nights stayed in the hospital

Question 3a = In the past 4 weeks, have you been hospitalized due to chronic low back pain or any medication used for chronic low back pain?

Question 1: number of office visits directly related to chronic low back pain or any medication used for chronic low back pain

Question 2: money (dollars) spent out-of-pocket on physical treatments in the past 4 weeks to manage chronic low back pain

Question 3b: nights stayed in the hospital

Observed steady-state plasma concentration (Cobs) of oxycodone and noroxycodone.

Cobs of naltrexone and 6-β-naltrexol

Observed steady-state plasma concentration (Cobs) of oxycodone and noroxycodone

Observed steady-state plasma concentration (Cobs) of naltrexone and 6-β-naltrexol