Trial Outcomes & Findings for Reinforcing Effects of Marijuana and Opioids (NCT NCT05485012)

Last Updated: 2026-04-15

Results Overview

The number of units of drug (out of a total of 7) earned in each experimental condition. Participants work for some, none, or all of the available drug dose. For each dose condition, the number of drug units completed for drug was pulled from the raw data and averaged to yield one mean (SEM).

Recruitment status

COMPLETED

Study phase

PHASE1

Target enrollment

8 participants

Primary outcome timeframe

Through a progressive-ratio self-administration model given once per treatment condition throughout each 6 hour session

Results posted on

2026-04-15

Participant Flow

Participant milestones

Participant milestones
Measure	Double-blind Marijuana/Placebo & Opioid/Placebo Administration Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid agonist/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an intranasal opioid agonist/placebo
Overall Study STARTED	8
Overall Study Oxycodone 0mg / Self-Admin Dose: THC 0mg	7
Overall Study Oxycodone 0mg / Self-Admin Dose: THC 10mg	6
Overall Study Oxycodone 0mg / Self-Admin Dose: THC 30mg	7
Overall Study Oxycodone 45mg / Self-Admin Dose: THC 0mg	7
Overall Study Oxycodone 45mg / Self-Admin Dose: THC 10mg	6
Overall Study Oxycodone 45mg / Self-Admin Dose: THC 30mg	6
Overall Study THC 0mg / Self-Admin Dose: Oxycodone 0mg	6
Overall Study THC 0mg / Self-Admin Dose: Oxycodone 15mg	6
Overall Study THC 0mg / Self-Admin Dose: Oxycodone 45mg	6
Overall Study THC 30mg / Self-Admin Dose: Oxycodone 0mg	6
Overall Study THC 30mg / Self-Admin Dose: Oxycodone 15mg	6
Overall Study THC 30mg / Self-Admin Dose: Oxycodone 45mg	6
Overall Study COMPLETED	6
Overall Study NOT COMPLETED	2

Reasons for withdrawal

Reasons for withdrawal
Measure	Double-blind Marijuana/Placebo & Opioid/Placebo Administration Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid agonist/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an intranasal opioid agonist/placebo
Overall Study Physician Decision	2

Baseline Characteristics

Reinforcing Effects of Marijuana and Opioids

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Double-blind Marijuana/Placebo & Opioid/Placebo Administration n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an intranasal opioid agonist/plcebo
Age, Continuous	39.7 years STANDARD_DEVIATION 8.4 • n=193 Participants
Sex: Female, Male Female	1 Participants n=193 Participants
Sex: Female, Male Male	5 Participants n=193 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=193 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	6 Participants n=193 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=193 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=193 Participants
Race (NIH/OMB) Asian	0 Participants n=193 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=193 Participants
Race (NIH/OMB) Black or African American	2 Participants n=193 Participants
Race (NIH/OMB) White	4 Participants n=193 Participants
Race (NIH/OMB) More than one race	0 Participants n=193 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=193 Participants
Region of Enrollment United States	6 participants n=193 Participants

PRIMARY outcome

Timeframe: Through a progressive-ratio self-administration model given once per treatment condition throughout each 6 hour session

Outcome measures

Outcome measures
Measure	Oxycodone 0mg / Self-Admin Dose: THC 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 0mg / Self-Admin Dose: THC 10mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 0mg / Self-Admin Dose: THC 30mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 10mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 30mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 15mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 45mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 15mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 45mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo
Self-Administration of Drug Units Earned	0.00 Number of drug units Standard Error 0.00	3.83 Number of drug units Standard Error 0.95	3.67 Number of drug units Standard Error 0.21	0.00 Number of drug units Standard Error 0.00	3.17 Number of drug units Standard Error 0.70	3.00 Number of drug units Standard Error 0.63	0.00 Number of drug units Standard Error 0.00	4.33 Number of drug units Standard Error 0.71	4.00 Number of drug units Standard Error 0.37	0.33 Number of drug units Standard Error 0.33	2.33 Number of drug units Standard Error 0.76	3.33 Number of drug units Standard Error 0.88

SECONDARY outcome

Timeframe: This outcome was recorded prior to and in regular intervals after drug administration for the duration of each session (approximately 6 hours).

Population: Per Protocol population, defined as participants completing the 12 experimental drug conditions.

End-tidal Carbon Dioxide (EtCO2): For each dose condition, the participants' peak value was pulled from the raw data and averaged to yield one mean (SEM). Higher scores indicate greater impairment.

Outcome measures

Outcome measures
Measure	Oxycodone 0mg / Self-Admin Dose: THC 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 0mg / Self-Admin Dose: THC 10mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 0mg / Self-Admin Dose: THC 30mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 10mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	Oxycodone 45mg / Self-Admin Dose: THC 30mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 15mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 0mg / Self-Admin Dose: Oxycodone 45mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 0mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 15mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo	THC 30mg / Self-Admin Dose: Oxycodone 45mg n=6 Participants Participants will receive double-blind administration of vaporized marijuana/placebo and intranasal opioid/placebo Marijuana: Double-blind administration of marijuana/placebo Opioid: Double-blind administration of an opioid agonist/placebo
Peak End-tidal Carbon Dioxide (EtCO2)	38.50 units (mmHg) Standard Error 0.85	39.17 units (mmHg) Standard Error 1.14	40.17 units (mmHg) Standard Error 1.08	43.50 units (mmHg) Standard Error 1.18	43.17 units (mmHg) Standard Error 1.11	45.50 units (mmHg) Standard Error 0.85	38.67 units (mmHg) Standard Error 1.12	42.50 units (mmHg) Standard Error 1.41	42.67 units (mmHg) Standard Error 1.93	40.83 units (mmHg) Standard Error 1.22	41.50 units (mmHg) Standard Error 1.06	42.00 units (mmHg) Standard Error 1.44

SECONDARY outcome

Timeframe: This outcome was recorded prior to and in regular intervals after drug administration for the duration of each session (approximately 6 hours).

Respiration rate (number of breaths per minute): For each dose condition, the participants' trough value was pulled from the raw data and averaged to yield one mean (SEM). Lower scores indicate greater impairment.