Trial Outcomes & Findings for Effect of Guanfacine on Opioid-induced Hyperalgesia (OIH) and Tolerance (NCT NCT01681264)

NCT ID: NCT01681264

Last Updated: 2026-07-31

Results Overview

Change in numeric pain score (from 0-10: 0 being no pain; 10 being worst pain) was used to measure changes in pain.

Recruitment status

TERMINATED

Study phase

PHASE4

Target enrollment

137 participants

Primary outcome timeframe

12 weeks; outcomes were assessed at the baseline and 12 weeks.

Results posted on

2026-07-31

Participant Flow

A total of 538 potential study participants were screened, 137 were enrolled, and 51 completed.

Participant milestones

Participant milestones
Measure	Morphine:Placebo Morphine Placebo	Morphine:Guanfacine 1mg Morphine Guanfacine 1mg	Morphine:Guanfacine 2mg Morphine Guanfacine 2mg	Placebo:Guanfacine 2mg Guanfacine 2mg Placebo	Placebo:Placebo Placebo
Overall Study STARTED	28	29	28	26	26
Overall Study COMPLETED	10	11	11	10	9
Overall Study NOT COMPLETED	18	18	17	16	17

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Effect of Guanfacine on Opioid-induced Hyperalgesia (OIH) and Tolerance

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Morphine:Placebo n=28 Participants Morphine Placebo	Morphine:Guanfacine 1mg n=29 Participants Morphine Guanfacine 1mg	Morphine:Guanfacine 2mg n=28 Participants Morphine Guanfacine 2mg	Placebo:Guanfacine 2mg n=26 Participants Guanfacine 2mg Placebo	Placebo:Placebo n=26 Participants Placebo	Total n=137 Participants Total of all reporting groups
Race (NIH/OMB) Asian	1 Participants n=9 Participants	2 Participants n=27 Participants	2 Participants n=267 Participants	1 Participants n=265 Participants	2 Participants n=568 Participants	8 Participants n=22 Participants
Age, Categorical <=18 years	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Age, Categorical Between 18 and 65 years	28 Participants n=9 Participants	29 Participants n=27 Participants	28 Participants n=267 Participants	26 Participants n=265 Participants	26 Participants n=568 Participants	137 Participants n=22 Participants
Age, Categorical >=65 years	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Age, Continuous	36 years n=9 Participants	42 years n=27 Participants	39 years n=267 Participants	41 years n=265 Participants	25 years n=568 Participants	28 years n=22 Participants
Sex: Female, Male Female	13 Participants n=9 Participants	14 Participants n=27 Participants	12 Participants n=267 Participants	10 Participants n=265 Participants	10 Participants n=568 Participants	59 Participants n=22 Participants
Sex: Female, Male Male	15 Participants n=9 Participants	15 Participants n=27 Participants	16 Participants n=267 Participants	16 Participants n=265 Participants	16 Participants n=568 Participants	78 Participants n=22 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Race (NIH/OMB) Black or African American	6 Participants n=9 Participants	4 Participants n=27 Participants	3 Participants n=267 Participants	4 Participants n=265 Participants	2 Participants n=568 Participants	19 Participants n=22 Participants
Race (NIH/OMB) White	21 Participants n=9 Participants	23 Participants n=27 Participants	23 Participants n=267 Participants	21 Participants n=265 Participants	22 Participants n=568 Participants	110 Participants n=22 Participants
Race (NIH/OMB) More than one race	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=9 Participants	0 Participants n=27 Participants	0 Participants n=267 Participants	0 Participants n=265 Participants	0 Participants n=568 Participants	0 Participants n=22 Participants
Region of Enrollment United States	28 participants n=9 Participants	29 participants n=27 Participants	28 participants n=267 Participants	26 participants n=265 Participants	26 participants n=568 Participants	137 participants n=22 Participants

PRIMARY outcome

Timeframe: 12 weeks; outcomes were assessed at the baseline and 12 weeks.

Population: Study participants enrolled in five study groups

Change in numeric pain score (from 0-10: 0 being no pain; 10 being worst pain) was used to measure changes in pain.