n-Acetylcysteine and Cocaine

Overview

This study will determine the initial efficacy, safety and tolerability of n-acetylcysteine as a pharmacotherapy for cocaine dependence. A rigorous, inpatient human laboratory study will be conducted in which the subjective, physiological and reinforcing effects of cocaine are evaluated during maintenance on placebo and n-acetylcysteine.

Full Title of Study: “Motivation for Cocaine and Non-Drug Reinforcers: Targeting Glutamate Homeostasis”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Basic Science
    • Masking: Triple (Participant, Care Provider, Outcomes Assessor)
  • Study Primary Completion Date: April 2016

Interventions

  • Drug: Cocaine
    • The pharmacodynamic effects of cocaine will be determined during maintenance on placebo and n-acetylcysteine.
  • Drug: n-Acetylcysteine
  • Drug: Placebo

Arms, Groups and Cohorts

  • Placebo Comparator: Placebo
    • Subjects will be maintained on oral placebo.
  • Experimental: n-Acetylcysteine
    • Subjects will be maintained on oral n-acetylcysteine.

Clinical Trial Outcome Measures

Primary Measures

  • Number of Times Cocaine Was Selected in the Presence of a Monetary Reward Alternative
    • Time Frame: One test per cocaine dose level per intervention for each participant over his/her approximate 2 week inpatient admission.
    • The reinforcing effects of cocaine were determined using a modified progressive ratio procedure (Stoops et al., 2010) in which subjects made 6 choices between available each available cocaine dose and money (US$0.25). Reinforcing effects are measured for each cocaine dose during both buspirone and placebo maintenance.

Secondary Measures

  • Peak Score on Sedative Subscale of the Adjective Rating Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects completed 16 items that loaded into the Sedative Subscale of the Adjective Rating Scale. The items were rated 0-4 on a Likert-type scale and the sum for the 16 “sedative” items was summed to yield the Sedative Subscale score. The maximum score for this scale was 64, the minimum was 0. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Score on Stimulant Subscale of the Adjective Rating Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects completed 16 items that loaded into the Stimulant Subscale of the Adjective Rating Scale. The items were rated 0-4 on a Likert-type scale and the sum for the 16 “sedative” items was summed to yield the Stimulant Subscale score. The maximum score for this scale was 64, the minimum was 0. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Active, Alert, Energetic” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Active, Alert, Energetic” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Any Effect” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Any Effect” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Bad Effects” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Bad Effects” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Euphoric” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Euphoric” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Good Effects” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Good Effects” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “High” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “High” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Irregular/Racing Heartbeat” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Irregular/Racing Heartbeat” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Like Drug” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Like Drug” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Nauseous” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Nauseous” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Nervous/Anxious” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Nervous/Anxious” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Willing to Pay For” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Willing to Pay For” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Performance Impaired” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Performance Impaired” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Performance Improved” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Performance Improved” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Restless” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Restless” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Rush” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Rush” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Shaky/Jittery” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Shaky/Jittery” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Sluggish/Fatigued/Lazy” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Sluggish/Fatigued/Lazy” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Stimulated” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Stimulated” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Willing to Take Again” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Willing to Take Again” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Ratings of “Talkative/Friendly” on the Visual Analog Scale
    • Time Frame: Subjects completed this measure at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Subjects rated their feelings of “Talkative/Friendly” on a Visual Analog Scale. This item was rated from 0 (minimum)-100 (maximum) on a Visual Analog Scale. Higher values represent greater subjective effects on this item. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Diastolic Blood Pressure
    • Time Frame: This measure was completed at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Diastolic blood pressure was measured with an automated monitor. Higher values represent greater diastolic pressure. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Systolic Blood Pressure
    • Time Frame: This measure was completed at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Systolic blood pressure was measured with an automated monitor. Higher values represent greater systolic pressure. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Heart Rate
    • Time Frame: This measure was completed at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Heart rate was measured with an automated monitor. Higher values represent greater heart rate. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.
  • Peak Temperature
    • Time Frame: This measure was completed at 15 minute intervals for 45 minutes after sampling each cocaine dose under both n-acetylcysteine and placebo maintenance conditions.
    • Oral temperature was measured with an automated monitor. Higher values represent greater temperature. Peak scores were calculated from multiple assessments for each cocaine dose under both n-acetylcysteine and placebo conditions.

Participating in This Clinical Trial

Inclusion Criteria

  • Current cocaine use – Current cigarette smoker Exclusion Criteria:

  • Abnormal screening outcome (e.g., ECG, blood chemistry result) that study physicians deem clinically significant – Current or past histories of substance abuse or dependence that are deemed by the study physicians to interfere with study completion – History of serious physical disease, current physical disease, impaired cardiovascular functioning, chronic obstructive pulmonary disease, history of seizure or current or past histories of serious psychiatric disorder that in the opinion of the study physician would interfere with study participation will be excluded from participation – Females not currently using effective birth control – Contraindications to cocaine or n-acetylcysteine – History of schizophrenia in first degree relative

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 55 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of Kentucky
  • Collaborator
    • National Institute on Drug Abuse (NIDA)
  • Provider of Information About this Clinical Study
    • Principal Investigator: William Stoops, Associate Professor – University of Kentucky

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