Pain Threshold, Mood
Conditions
Keywords
oral thc, cannabis, pain, analgesic effects, dronabinol
Brief summary
The following study is designed to determine the analgesic efficacy of smoked marijuana (0, 1.98, and 3.56% THC) and oral THC (0, 10, and 20 mg) in the Cold-Pressor Test (CPT), a laboratory model of pain which has predictive validity for clinical use of analgesics. Oral THC (dronabinol) is known to have a slower onset and longer duration of action compared with smoked marijuana. Therefore, the analgesic effects of oral THC is expected to peak later and last longer than effects produced by smoked marijuana.
Detailed description
Laboratory animal studies have demonstrated the analgesic effects of drugs which act on the cannabinoid system, however, these effects have et to be clearly elucidated in humans. To better understand the potential clinical application of cannabinoids for pain management, the following study is designed to determine the analgesic efficacy of smoked marijuana (3.56% THC) and oral THC (20 mg) in the Cold-Pressor Test (CPT), a laboratory model of pain which has predictive validity for clinical use of analgesics. Non-treatment seeking marijuana smokers will be recruited for a five-session study during which the analgesic, subjective, and physiologic effects of cannabinoids will be evaluated. Determining the efficacy of cannabinoids in an experimental model of pain will provide important endpoints (i.e., dose, route of administration, time course) or this effect to further investigate the potential role for clinical use of smoked marijuana and/or oral THC as analgesics.
Interventions
DRUGPlacebo capsules
Placebo capsules
Inactive marijuana cigarettes (0% THC) provided by NIDA
DRUGLow dose Dronabinol
Dronabinol 10mg
DRUGHigh dose Dronabinol
Dronabinol 20mg
DRUGLow THC marijuana
marijuana cigarettes (1.98% THC) provided by NIDA
DRUGHigh THC marijuana
Marijuana cigarettes (3.56% THC) provided by NIDA
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
OTHER
Masking
DOUBLE (Subject, Investigator)
Masking description
Placebo-controlled, double-blind
Eligibility
Sex/Gender
FEMALE
Age
21 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Adults between the ages of 21-45 * Current marijuana use * Able to perform study procedures * Women practicing an effective form of birth control
Exclusion criteria
* Female subjects who are currently pregnant or breastfeeding * Current,repeated illicit drug use other than marijuana * Presence of significant medical illness * History of heart disease * Request for drug treatment * Current parole or probation * Recent history of significant violent behavior
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pain Tolerance | Within each session lasting approximately 5 minutes, for a total of five sessions | Change in pain tolerance from baseline (in seconds) as a function of drug condition. The cold pressor test was administered during each session to examine changes in pain threshold (how many seconds it takes for a participant to begin feeling pain after cold water immersion). |
Countries
United States
Participant flow
Pre-assignment details
Thirty-four participants were enrolled, and 30 completed. A total of 30 participants completed all 5 treatment combinations in randomized order.
Participants by arm
| Arm | Count |
|---|---|
| Overall Number of Baseline Participants 34 participants were enrolled, but only 30 participants completed. Out of the additional 4 volunteers, 1 discontinued for personal reasons and three were unreliable. | 30 |
| Total | 30 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | unreliable | 3 |
| Overall Study | Withdrawal by Subject | 1 |
Baseline characteristics
| Characteristic | Overall Number of Baseline Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 30 Participants |
| Region of Enrollment United States | 30 Participants |
| Sex: Female, Male Female | 15 Participants |
| Sex: Female, Male Male | 15 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 |
|---|---|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 34 | 0 / 34 | 0 / 34 | 0 / 34 | 0 / 34 |
| serious Total, serious adverse events | 0 / 34 | 0 / 34 | 0 / 34 | 0 / 34 | 0 / 34 |
Outcome results
Primary
Pain Tolerance
Change in pain tolerance from baseline (in seconds) as a function of drug condition. The cold pressor test was administered during each session to examine changes in pain threshold (how many seconds it takes for a participant to begin feeling pain after cold water immersion).
Time frame: Within each session lasting approximately 5 minutes, for a total of five sessions
Population: All participants who completed the study (N=30) were included in the final analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| High Dose Dronabinol + Inactive Marijuana | Pain Tolerance | 6.1 seconds | Standard Error 4.4 |
| Low Dose Dronabinol + Inactive Marijuana | Pain Tolerance | 2.8 seconds | Standard Error 2.9 |
| Placebo + Low THC Marijuana | Pain Tolerance | 4.9 seconds | Standard Error 3.4 |
| Placebo + High THC Marijuana | Pain Tolerance | 1.5 seconds | Standard Error 1.4 |
| Placebo + Inactive Marijuana 0% THC | Pain Tolerance | 1.5 seconds | Standard Error 1.4 |