Marijuana Smoking
Conditions
Keywords
naltrexone, smoked marijuana, marijuana use
Brief summary
In heavy marijuana smokers, opioid receptor blockade increases the subjective and cardiovascular effects of marijuana. The current study was designed to clarify opioid-cannabinoid interactions by assessing how naltrexone shifts the dose-response function for marijuana-elicited effects in heavy marijuana smokers. For this within-subject, double-blind study, a marijuana smoking procedure was designed to characterize a dose-response relationship for marijuana's subjective and cardiovascular effects under blinded conditions.
Interventions
Marijuana cigarette containing 0% THC
DRUGActive Marijuana (5.5% THC)
Marijuana cigarette containing 5.5% THC
DRUGActive Marijuana (6.2% THC)
Marijuana cigarette containing 6.2% THC
DRUGNaltrexone
Naltrexone (12mg/70kg)
Naltrexone (0mg)
Sponsors
Research Foundation for Mental Hygiene, Inc.
National Institute on Drug Abuse (NIDA)
New York State Psychiatric Institute
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Masking description
Double-blind, placebo-controlled
Eligibility
Sex/Gender
ALL
Age
21 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Current marijuana use * Able to perform study procedures * Women practicing an effective form of birth control
Exclusion criteria
* Current repeated illicit drug use (other than marijuana) * Presence of significant medical illness (e.g., diabetes, cardiovascular disease,hypertension, hepatitis, clinically significant laboratory abnormalities, LFTs \> 3x upper limit of normal, blood pressure \> 140/90
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Subjective Marijuana Effects | 180 minutes after marijuana administration, during each of 8 outpatient sessions over the course of 3-6 weeks. | Subjective ratings of marijuana's quality and effect ('Strength', 'Good Effect', 'High', 'Stimulation') and craving ('Want Marijuana') as a function of active puffs and naltrexone, using a visual analogue scale with a series of 100 mm long lines labeled 'not at all' at one end (0 mm) and 'extremely' at the other end (100 mm). Participants were instructed to indicate how they felt at that particular moment. Higher ratings indicate more agreement with the statement. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Placebo, Naltrexone, Marijuana During each of the 8 outpatient sessions, participants smoked a total of 6 puffs from 3 marijuana cigarettes (2 puffs from each cigarette). Marijuana administration occurred 45 minutes after capsule administration. The number of active versus inactive cigarettes smoked during each session varied, according to active puff conditions (i.e., 0 puffs = 3 inactive cigarettes; 2 puffs = 1 active + 2 inactive cigarette; 4 puffs = 2 active + 1 inactive cigarette; 6 puffs = 3 active + 0 inactive cigarette). Cigarettes were color coded, indicating the order in which they were to be smoked and active cigarettes were always smoked before inactive. A within-subject design was used in which all participants were exposed to each of the puff conditions in combination with naltrexone or placebo. The order of naltrexone dosing and puff condition was randomized within the session and across participants. | 19 |
| Total | 19 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Adverse Event | 2 |
| Overall Study | Pregnancy | 1 |
| Overall Study | Withdrawal by Subject | 1 |
Baseline characteristics
| Characteristic | Placebo, Naltrexone, Marijuana |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 19 Participants |
| Age, Continuous | 27.0 years STANDARD_DEVIATION 4 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 10 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 1 Participants |
| Race (NIH/OMB) White | 8 Participants |
| Region of Enrollment United States | 19 Participants |
| Sex: Female, Male Female | 1 Participants |
| Sex: Female, Male Male | 18 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk | EG005 affected / at risk |
|---|---|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 |
| other Total, other adverse events | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 |
| serious Total, serious adverse events | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 | 0 / 23 |
Outcome results
Primary
Subjective Marijuana Effects
Subjective ratings of marijuana's quality and effect ('Strength', 'Good Effect', 'High', 'Stimulation') and craving ('Want Marijuana') as a function of active puffs and naltrexone, using a visual analogue scale with a series of 100 mm long lines labeled 'not at all' at one end (0 mm) and 'extremely' at the other end (100 mm). Participants were instructed to indicate how they felt at that particular moment. Higher ratings indicate more agreement with the statement.
Time frame: 180 minutes after marijuana administration, during each of 8 outpatient sessions over the course of 3-6 weeks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Strength | 13 units on a scale (0-100mm) | Standard Error 1 |
| Placebo Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Stimulation | 16 units on a scale (0-100mm) | Standard Error 2 |
| Placebo Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana High | 10 units on a scale (0-100mm) | Standard Error 1 |
| Placebo Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Good Effect | 14 units on a scale (0-100mm) | Standard Error 2 |
| Placebo Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Want Marijuana | 50 units on a scale (0-100mm) | Standard Error 1.5 |
| Placebo Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Stimulation | 20 units on a scale (0-100mm) | Standard Error 2 |
| Placebo Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Good Effect | 37 units on a scale (0-100mm) | Standard Error 3 |
| Placebo Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Strength | 15 units on a scale (0-100mm) | Standard Error 1 |
| Placebo Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana High | 10.5 units on a scale (0-100mm) | Standard Error 0.5 |
| Placebo Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Want Marijuana | 48 units on a scale (0-100mm) | Standard Error 1 |
| Placebo Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Good Effect | 30 units on a scale (0-100mm) | Standard Error 2.5 |
| Placebo Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Strength | 16 units on a scale (0-100mm) | Standard Error 2 |
| Placebo Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Want Marijuana | 37 units on a scale (0-100mm) | Standard Error 1.5 |
| Placebo Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Stimulation | 16 units on a scale (0-100mm) | Standard Error 2 |
| Placebo Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana High | 10 units on a scale (0-100mm) | Standard Error 1 |
| Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Good Effect | 31 units on a scale (0-100mm) | Standard Error 3 |
| Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Want Marijuana | 49 units on a scale (0-100mm) | Standard Error 1 |
| Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Strength | 16 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana Stimulation | 20 units on a scale (0-100mm) | Standard Error 1.5 |
| Naltrexone + Active Marijuana (5.5% THC) | Subjective Marijuana Effects | Marijuana High | 11 units on a scale (0-100mm) | Standard Error 1.5 |
| Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Want Marijuana | 45 units on a scale (0-100mm) | Standard Error 1.5 |
| Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Strength | 20 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Good Effect | 46 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana High | 16 units on a scale (0-100mm) | Standard Error 1.5 |
| Naltrexone + Active Marijuana (6.2% THC) | Subjective Marijuana Effects | Marijuana Stimulation | 30 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Stimulation | 22 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana High | 10 units on a scale (0-100mm) | Standard Error 1.5 |
| Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Good Effect | 26 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Marijuana Strength | 16 units on a scale (0-100mm) | Standard Error 2 |
| Naltrexone + Inactive Marijuana | Subjective Marijuana Effects | Want Marijuana | 50 units on a scale (0-100mm) | Standard Error 1.5 |