Project 2, Study 2: Extended Exposure to Low Nicotine Content Cigarettes in Opioid Abusers

This study will examine extended exposure to cigarettes varying in nicotine content among adults with opioid use disorder. Those with opioid use disorder are at increased risk for smoking, nicotine dependence, and using high nicotine yield cigarettes and are also at significantly increased risk for smoking-related adverse health consequences, including site specific cancers, heart disease, and premature death. Studies testing an innovative regulatory strategy of reducing the nicotine content of cigarettes to a non-addictive level have shown promising beneficial effects (decreased smoking rate, reduced toxicant exposure, and increased cessation) in the general population of smokers. However, these studies have uniformly excluded vulnerable populations like those with opioid use disorder who may respond differently considering their greater vulnerability to smoking and nicotine dependence. Thus, little is known scientifically about how this highly vulnerable subgroup of smokers might respond to a nicotine reduction policy. This project is designed to address that substantial knowledge gap. This same study was also conducted in two additional vulnerable populations under a similar protocol.

The primary overall objective of these studies is to evaluate the effects of extended exposure to cigarettes differing in nicotine content in adults with opioid use disorder using a 3-condition, parallel groups design. After a baseline period in which daily smoking rate and other baseline assessments are completed, participants will be randomly assigned to one of three cigarette conditions (nicotine content: 0.04, 2.4, and 15.8 mg nicotine/gram of tobacco) for the 12-week experimental period.

The cigarettes to be used in this study were made under an NIH contract with production being overseen by the Research Triangle Institute (referred to as "Spectrum cigarettes"). NIH currently has approximately 10 million of these cigarettes (of varying types) for research purposes. The cigarettes selected for the study span the range of yields likely to produce the hypothesized effects, as described above. The Spectrum cigarettes are not currently commercially available, although they are similar in many ways to marketed cigarettes (e.g., similar manufacturing, filter, paper, etc.).

The primary overall objective of this study is to evaluate the effects of extended exposure to cigarettes differing in nicotine content in male and female adults with opioid use disorder using a 3-condition, parallel groups design. After a baseline period in which daily smoking rate and other baseline assessments are completed, participants will be randomly assigned to one of three cigarette conditions (nicotine content: 0.04 mg, 2.4 mg, and 15.8 mg nicotine/g of tobacco) for the 12-week experimental period.

Participants will be seen weekly throughout the 12-week experimental period to obtain research cigarettes. Cigarettes smoked per day will be obtained by participants completing daily Interactive Voice Response (IVR) reports of cigarettes in past 24 hours. This daily data will be used to calculate weekly means, with week-12 means serving as the primary outcome.

This same study was conducted in two additional vulnerable populations under a similar protocol, with differences between protocols consisting of data collection specific to that vulnerable population. This included information such as additional assessments of anxiety and depression for individuals with affective disorders or other measures specific to disadvantaged women of reproductive age. In order to explore potential differences across individuals with different vulnerabilities, data from all three studies were combined for analysis. A vulnerable population-by-condition or population-by-condition-by-time interaction term was included in all analyses. In the event that these interaction terms were statistically significant, all pairwise comparisons were conducted using a Bonferroni multiple comparison adjustment.

Eligibility Criteria:
Inclusion Criteria:

1. Men and women ages 18-70, who are currently receiving methadone or buprenorphine maintenance treatment for opioid dependence.
2. Report smoking ≥ 5 cigarettes per day.
3. Provide an intake breath carbon monoxide (CO) sample \>8 ppm.
4. Be without current (within the past year) serious mental disorder that would interfere with study results or completion as determined by the licensed medical professional or PI.
5. Be sufficiently literate to complete the research-related tasks.
6. Be in good physical health without serious illness or change in health or medication (not including methadone or buprenorphine dose) in the past three months as determined by the license medical professional at each site.
7. Not pregnant or nursing, and report using oral, implant, injection or barrier contraceptives, or report being surgically sterile, or post menopausal.
8. Report no significant use of other tobacco or nicotine products within the past month (more than 9 days in the past 30).
9. Participants must be maintained on a stable methadone or buprenorphine dose for the past month, with no evidence of regular illicit-drug abuse (\<30% positive specimens in the past 30 days).

   1. Consent to confirm dose and drug abstinence with the participant's opioid clinic will be obtained at screening and we will monitor any changes in dose throughout the study.
   2. Participants must provide at least three urine samples within the last 30 days. If they do not have three they will be asked to come in and provide a sample. They may leave up to two samples per week with at least one full day between samples.

Exclusion Criteria:

1. Any prior regular use (used as primary cigarette outside of laboratory) of Spectrum cigarettes (i.e., research cigarettes with reduced nicotine content).
2. Exclusive use of roll-your-own cigarettes.
3. Planning to quit smoking in the next 30 days.
4. A quit attempt in the past 30 days resulting in greater than 3 days of abstinence.
5. Currently taking anticonvulsant medications.
6. Positive toxicology screen for illicit drugs not including Marijuana ( participants with valid prescriptions will not be excluded and participants with a positive toxicology screen will be allowed to re-screen once).
7. Not currently enrolled in a treatment program for opioid dependence and/or not currently stable on their methadone or buprenorphine dose.
8. Breath alcohol level \> 0.01 ( participants with a positive screen will be allowed to re-screen once).
9. Self-report of binge drinking alcohol (more than 9 days in the past 30 days, 4/5 drinks in a 2 hour period in females/males),
10. Blood pressure is greater than or equal to 160/100 mmHg or below 90/50 mmHg (participants outside the range will be allowed to re-screen once).

    a. Participants failing for blood pressure will be allowed to re-screen once.
11. Breath CO \> 80 ppm.
12. Heart rate is greater than or equal to 115 bpm or less than 45 bpm ( participants outside the range will be allowed to re-screen once).
13. Currently seeking treatment for smoking cessation.
14. Have used nicotine replacement, bupropion or other pharmacotherapies as cessation aids in the past month (bupropion will be allowed for treatment of depression).
15. Current symptoms of psychosis or dementia, or mania.
16. Suicidal ideation in the past month. 17.) Suicide attempt in the past 6 months. 18.) Participation in another research study in the past 30 days.