Clinical trial NCT00403117: Effects of a Range of Naltrexone Doses in Combination With Smoked Marijuana
Official title: Opioid Antagonism Enhances Marijuana's Effects in Heavy Marijuana Smokers
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Marijuana Use
Keywords: Naltrexone
Smoked Marijuana
Lead sponsor: New York State Psychiatric Institute
Sponsor class: OTHER
Collaborators: name: Research Foundation for Mental Hygiene, Inc.
name: National Institute on Drug Abuse (NIDA)
First posted: 2006-11-23
Enrollment: 49
Sex: ALL
Minimum age (years): 21
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: The purpose of this study is to determine if the subjective effects of marijuana will be decreased by low-doses (\< 25 mg) of naltrexone and increased by high-doses (\> 50 mg) of naltrexone.

Detailed description: Laboratory animal studies demonstrate that endogenous cannabinoids and opioids are closely inter-related. We have completed a series of studies in marijuana smokers showing that a clinically-utilized dose of naltrexone (50 mg) enhanced the reinforcing and subjective effects of orally-administered tetrahydrocannabinol (THC), while a low naltrexone dose (12 mg) blunted the effects of THC. A better understanding of the effects of a range of naltrexone doses in combination with smoked marijuana has important implications for the following reasons: (1) Alcohol- and opioid-dependent patients receive high doses of naltrexone (50-150 mg), which may increase the abuse liability of marijuana, (2) Low-dose naltrexone blunts THC's intoxicating effects, suggesting potential utility as a treatment medication for marijuana dependence. This study will determine if naltrexone (0, 12, 25, 50, 100 mg) administration 45 min prior to marijuana administration (0, 3.27% THC) alters marijuana's subjective, cognitive or physiological effects. Marijuana smokers will spend approximately 5h/day for a total of 10 days in the outpatient laboratory. Participants will visit the outpatient laboratory 2-3 times per week, with a minimum 48-hr interval between sessions to allow for naltrexone clearance. These data will provide important information regarding the clinical use of naltrexone.

Eligibility criteria: Inclusion Criteria:

* Current marijuana use
* Able to perform study procedures
* 21-45 years of age
* 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, examination, laboratory hepatitis, clinically significant laboratory abnormalities, tests, 12-lead ECG, Mantoux test LFTs \> 3x upper limit of normal)
* History of heart disease
* Request for drug treatment
* Current parole or probation
* Pregnancy or current lactation
* Recent history of significant violent behavior
* Previous adverse reaction to naltrexone
* Major current Axis I psychopathology Psychiatric interview (e.g., major depressive disorder, bipolar disorder, suicide risk, schizophrenia)
* Current use of any prescription or over-the-counter medication

Primary outcomes:
measure: Change in Mean Subjective Mood Scores as a Function of Marijuana Strength and Naltrexone Dose.
timeFrame: Baseline compared to 6 week timepoint
measure: Change in Mean Psychomotor Task Performance as a Function of Marijuana Strength and Naltrexone Dose
timeFrame: Baseline compared to 6 week timepoint
measure: Change in Mean Heart Rate as a Function of Marijuana Strength and Naltrexone Dose.
timeFrame: Baseline compared to 6 week timepoint
Secondary outcomes:
Other outcomes:
Locations:
Study officials:
affiliation: New York State Psychiatric Institute
name: Margaret Haney, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: