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Effects of Naltrexone on Nicotine Reinforcement

This study has been completed.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
University of Pennsylvania
ClinicalTrials.gov Identifier:
NCT00270231
First received: December 23, 2005
Last updated: November 12, 2013
Last verified: November 2013
  Purpose

Despite preclinical evidence supporting the role of the endogenous opioid system in the reinforcing effects of nicotine, the efficacy of the opioid antagonist naltrexone (NTX) as a tobacco dependence treatment remains unresolved. Research is needed to identify those smokers for whom NTX will have the strongest beneficial effects on smoking behavior.

The research bridges existing knowledge of genetic, pharmacologic, and behavioral responses to nicotine, and translates this knowledge to treatment for tobacco dependence. The immediate goal was to test whether genetic variation in the mu-opioid receptor gene predicts the effects of naltrexone (NTX) on nicotine reinforcement.


Condition Intervention Phase
Tobacco Dependence
Drug: Naltrexone
Drug: Placebo
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Official Title: Pharmacogenetic Investigation of Naltrexone

Resource links provided by NLM:


Further study details as provided by University of Pennsylvania:

Primary Outcome Measures:
  • Number of Nicotine Cigarette Choices Taken During the Cigarette Choice Procedure. [ Time Frame: 2 hours ] [ Designated as safety issue: No ]

    On day 4 of each study medication period, participants completed a cigarette choice procedure where the subject is asked to take 4 puffs from a nicotinized (nicotine-containing) or a denicotinized (no nicotine) cigarette every 30 minutes for 2 hours (maximum of 24 puffs). The outcome variable is the number of nicotine cigarette choices or puffs out of 24 total puffs during these cigarette choice procedures.

    Subjects who had the A/A genotype took an average of 18.5 puffs from the nicotine-containing cigarettes. Subjects with the A/G or G/G genotypes took an average of 16.2 puffs from the nicotine-containing cigarettes.



Enrollment: 64
Study Start Date: March 2004
Study Completion Date: October 2005
Primary Completion Date: October 2005 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Naltrexone

All participants took naltrexone during one of the two 4-day study medication periods. Both 4-day study medication periods were randomized and counterbalanced between naltrexone and placebo; all study medication periods were separated by a 5-7 day washout period.

Dosing of the naltrexone was the same for all participants: Day 1: 12.5mg, Day 2: 25mg, Days 3 and 4: 50mg.

Drug: Naltrexone

All participants took naltrexone during one of the two 4-day study medication periods. Both 4-day study medication periods were randomized and counterbalanced between naltrexone and placebo; all study medication periods were separated by a 5-7 day washout period.

Dosing of the naltrexone was the same for all participants: Day 1: 12.5mg, Day 2: 25mg, Days 3 and 4: 50mg.

Other Name: Revia or Trexan
Placebo Comparator: Placebo

All participants took a placebo (sugar pill) during one of the two 4-day study medication periods. Both 4-day study medication periods were randomized and counterbalanced between naltrexone and placebo.

Placebo capsules matched the naltrexone in color, weight and inactive ingredients. The only difference the lack of active naltrexone in each capsule.

Drug: Placebo

All participants took a placebo (sugar pill) during one of the two 4-day study medication periods. Both 4-day study medication periods were randomized and counterbalanced between naltrexone and placebo.

Placebo capsules matched the naltrexone in color, weight and inactive ingredients. The only difference the lack of active naltrexone in each capsule.

Other Name: Sugar pill; inactive medication

Detailed Description:

The study was a within-subject double-blind study of the effects of naltrexone versus placebo on the reinforcing value of nicotine, using a validated cigarette choice paradigm. A key question was whether smokers differ in their responses based on the mu opioid receptor gene (OPRM1) Asn40Asp (A118G) variant.

Following informed consent, 64 smokers were enrolled in the study. Of these, 60 completed two 4-day study phases interspersed with a 5-7 day washout phase. Baseline statistics are provided for the 64 smokers who enrolled.

Each 4-day study phase included a 3-day drug run-up and monitoring phase, then on the 4th day participants came to our Biobehavioral Lab (BBL) where they took their final 50mg of study medication and completed a cigarette choice paradigm. Following a washout phase, the 4-day sequence will be repeated with the alternative study medication. The order of study medication was randomized and counterbalanced between subjects.

  Eligibility

Ages Eligible for Study:   18 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  1. Participants must be greater than or equal to 18 years
  2. Based on the medical history, physical and laboratory examination, female subjects must:

    1. Agree in consent to practice effective contraception during study, be status post-bilateral tubal litigation or be post-menopausal.
    2. Not be pregnant, nursing, or planning pregnancy
  3. Based upon self-report, subjects must smoke greater than or equal to 10 non-menthol cigarettes per day
  4. Because the OPRM1 variant is common (25-30%) in persons of European ancestry, but very rare in other ethnic groups (e.g., 2-9% of African Americans) it is not scientifically justified to include members of other ethnic groups. Therefore, only persons of European ancestry will be recruited.
  5. Following orientation by the research staff, subjects must sign written informed consent and HIPAA form.

Exclusion Criteria:

  1. Current diagnosis of kidney disease or history of renal function impairment (unless they have recent kidney function tests (within last 3 months) and approval of their primary physician to participate in the study.)
  2. Women who are pregnant, planning a pregnancy, or lactating
  3. Current alcohol use > 25 standard drinks/week (this is because NTX is used to treat alcohol dependence, and effects of NTX on alcohol consumption in alcohol dependent subjects could have indirect effects on cigarette consumption).
  4. Current medical problems for which NTX is contraindicated including: active hepatitis (Liver Function Tests 3 times the Upper Limit of Normal).
  5. History of opiate dependence (prescription drug or illicit use).
  6. History of or current Diagnostic and Statistical Manual of Mental Disorders (Version IV) (DSM IV) substance use disorders (abuse or dependence involving alcohol, cocaine, stimulants, or benzodiazepines)
  7. Diagnosis of bulimia and/or anorexia nervosa in the last year
  8. Current or past use (with in past 12 months) of any medications containing NTX (e.g., Revia, Trexan), allergy to NTX
  9. Concomitant medications (e.g., monoamine oxidase inhibitors or benzodiazepines within past 14 days, antipsychotics, antidepressants, theophylline, systemic steroids, over-the-counter stimulants and anorectics)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00270231

Locations
United States, Pennsylvania
Tobacco Use Research Center
Philadelphia, Pennsylvania, United States, 19104
Sponsors and Collaborators
University of Pennsylvania
Investigators
Principal Investigator: Caryn Lerman, Ph.D. University of Pennsylvania
  More Information

Publications:
Responsible Party: University of Pennsylvania
ClinicalTrials.gov Identifier: NCT00270231     History of Changes
Other Study ID Numbers: 800810, R01DA017555
Study First Received: December 23, 2005
Results First Received: February 18, 2009
Last Updated: November 12, 2013
Health Authority: United States: Food and Drug Administration

Keywords provided by University of Pennsylvania:
within-subjects, crossover, laboratory study
Naltrexone vs. Placebo

Additional relevant MeSH terms:
Naltrexone
Central Nervous System Agents
Narcotic Antagonists
Peripheral Nervous System Agents
Pharmacologic Actions
Physiological Effects of Drugs
Sensory System Agents
Therapeutic Uses

ClinicalTrials.gov processed this record on November 27, 2014