N-Acetylcysteine and Smoking Reduction

This study has been completed.
National Institute on Drug Abuse (NIDA)
Information provided by:
Medical University of South Carolina
ClinicalTrials.gov Identifier:
First received: September 10, 2008
Last updated: September 11, 2012
Last verified: September 2008
N-acetylcysteine is an inexpensive agent with a benign side effect profile with preliminary studies in humans suggesting efficacy for the treatment of cocaine dependence. N-acetylcysteine has been used in clinical medicine for nearly three decades to treat chronic lung conditions, acetaminophen overdose, and experimentally to treat cocaine dependence. It is generally safe and well tolerated. The present pilot study seeks to explore safety and tolerability, ad lib smoking, visual cue reactivity, and smoking reduction rates in a group of nontreatment seeking, nicotine dependence smokers who are willing to undergo a brief trial with oral N-acetylcysteine 1200 mg twice daily.

Condition Intervention Phase
Nicotine Dependence
Drug: N-acetylcysteine
Drug: Placebo
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Randomized Controlled Trial of Oral N-acetylcysteine for Smoking Reduction: a Pilot Study

Resource links provided by NLM:

Further study details as provided by Medical University of South Carolina:

Primary Outcome Measures:
  • Carbon Monoxide Levels [ Time Frame: Weekly ] [ Designated as safety issue: No ]
  • Smoking Level [ Time Frame: Weekly ] [ Designated as safety issue: No ]
  • Craving Levels (Questionnaire for Smoking Urges -- Brief) [ Time Frame: Weekly ] [ Designated as safety issue: No ]
  • Minnesota Nicotine Withdrawal Scale (MNWS) [ Time Frame: Weekly ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Smoking Level [ Time Frame: Daily ] [ Designated as safety issue: No ]

Enrollment: 33
Study Start Date: December 2006
Study Completion Date: October 2007
Primary Completion Date: October 2007 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
2400mg N-acetylcysteine (1200mg b.i.d.) for 4 consecutive weeks
Drug: N-acetylcysteine
2400mg (1200mg b.i.d., 600mg capsules, p.o.)
Placebo Comparator: 2
Identically appearing placebo pills, packaged in an N-acetylcysteine "slurry" so that placebo will retain smell similar to active NAC capsules
Drug: Placebo
Identically appearing placebo capsules, packaged in an N-acetylcysteine "slurry" so that placebo has similar odor as active NAC capsules


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

Inclusion Criteria:

  1. Be smokers motivated to reduce their cigarette usage but not seeking treatment to quit smoking at the time of screening.
  2. Be Able to give written informed consent after being presented with an IRB-approved informed consent document
  3. Be male or female of any race, between eighteen and sixty five years of age.
  4. Be in stable physical and mental health as judged by interview
  5. Be smoking 10 or more cigarettes per day for one or more years
  6. Have an expired CO reading of ≥10 parts/million prior to beginning study
  7. Test non-pregnant and use adequate birth control (female only). All female subjects will have a urine pregnancy test performed prior to the first dose of study medication.
  8. Be able to comply with protocol requirements and be likely to complete all study treatments.
  9. Live within 50 miles of the study site

Exclusion Criteria:

  1. Have current dependence, defined by DSM IV criteria, on any psychoactive substance other than nicotine, alcohol, or marijuana or physiological dependence on alcohol requiring medical detoxification.
  2. Have a history of significant hepatic, renal, endocrine, cardiac (i.e., arrhythmia requiring medication, angina pectoris, myocardial infarction,), stroke, seizure, neurological, non-drug-related psychiatric, gastrointestinal, pulmonary, hematologic or metabolic disorders.
  3. Have a history of adverse reaction/hypersensitivity to N-acetylcysteine.
  4. Have any significant active medical or psychiatric illness (e.g. schizophrenia, suicidal/homicidal ideation within the past 30 days) which might inhibit their ability to complete the study or might be complicated by administration of NAC.
  5. Used carbamazepine or Nitroglycerin within the last 14 days or any other medication felt to be hazardous if taken with NAC
  6. Have a current or past history of asthma and/or the occasional or daily use of Albuterol or other beta-agonist inhalers.
  7. Females pregnant or breast-feeding
  8. Have any medical history or condition considered by the investigator(s) to place the subjects at increased risk.
  9. Not fail to actively meet the inclusion criteria at the time of screening.
  10. Have a history of childhood or adult seizures of any cause.
  11. Be currently taking any medications (i.e., beta-blockers, stimulant medications) that might affect heart rate or skin conductance
  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: NCT00751257

United States, South Carolina
Medical University of South Carolina
Charleston, South Carolina, United States, 29425
Sponsors and Collaborators
Medical University of South Carolina
National Institute on Drug Abuse (NIDA)
  More Information

Responsible Party: Steven D. LaRowe, Ph.D.; Research Assistant Professor, Principal Investigator, Medical Univeristy of South Carolina
ClinicalTrials.gov Identifier: NCT00751257     History of Changes
Other Study ID Numbers: P50DA015369 
Study First Received: September 10, 2008
Last Updated: September 11, 2012
Health Authority: United States: Food and Drug Administration
United States: Federal Government

Keywords provided by Medical University of South Carolina:
smoking reduction

Additional relevant MeSH terms:
Anti-Infective Agents
Antiviral Agents
Free Radical Scavengers
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Protective Agents
Respiratory System Agents

ClinicalTrials.gov processed this record on May 25, 2016