Effects of a Range of Naltrexone Doses in Combination With Smoked Marijuana
Condition: Marijuana Use
MeSH terms: Marijuana Abuse; Marijuana Use
Study type: Interventional
Phase: Phase 2

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.
    

Intervention name(s): Placebo + Inactive Marijuana (0% THC); Placebo + Active Marijuana (3.27% THC); Naltrexone 12 Mg+ Active Marijuana (3.27% THC); Naltrexone 25 Mg + Active Marijuana (3.27% THC); Naltrexone 50 Mg+ Active Marijuana (3.27% THC); Naltrexone 100 Mg+ Active Marijuana (3.27% THC); Naltrexone 12 Mg + Inactive Marijuana (0% THC); Naltrexone 25 Mg + Inactive Marijuana (0% THC); Naltrexone 50 Mg + Inactive Marijuana (0% THC); Naltrexone 100 Mg + Inactive Marijuana (0% THC)
Intervention type(s): Drug; Drug; Drug; Drug; Drug; Drug; Drug; Drug; Drug; Drug
Intervention description(s): One capsule containing placebo was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before marijuana administration.; One capsule containing placebo was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before administration of a marijuana cigarette containing 3.27% THC (ca. 800 mg) provided by the National Institute on Drug Abuse.; One capsule containing 12mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before active marijuana administration.; One capsule containing 12mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before active marijuana administration.; One capsule containing 25mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before marijuana administration.; One capsule containing 50mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before marijuana administration.; One capsule containing 12mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before inactive marijuana administration.; One capsule containing 25mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before inactive marijuana administration.; One capsule containing 50mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before inactive marijuana administration.; One capsule containing 100mg Naltrexone was administered to the participant in a size 00 opaque capsules with lactose filler 45 minutes before inactive marijuana administration.
Other intervention name(s): treatment type 1; treatment type 2; Treatment type 3; treatment type 4; treatment type 5; treatment type 6; treatment type 7; treatment type 8; treatment type 9; treatment type 10
Intervention MeSH terms: Naltrexone
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science
Keywords: Naltrexone; Smoked Marijuana