Please select the eligibility criteria that correspond to the clinical trial below.
Title: Varenicline for the Treatment of Smokeless Tobacco Use
Brief Summary: Varenicline (Chantix™, Pfizer) is a novel selective nicotinic receptor partial agonist with specificity for the α4β2 nicotine acetylcholine receptor that has demonstrated remarkable efficacy for increasing long-term tobacco abstinence rates in cigarette smokers. The novel mechanism of action of varenicline potentially circumvents the limitations of using nicotine replacement therapy or bupropion pharmacotherapy in ST users. The overall goal of this line of research is to develop effective pharmacologic treatments for ST users to increase long-term (≥ 6 months) abstinence rates. The central hypothesis of this application is that varenicline is efficacious for the treatment of ST users.


Options:
A: Inclusion Criteria:

1. self-identify as African American or Black;
2. age 18 years or older;
3. smoke at least five cigarettes daily for the past year;
4. not interested in quitting smoking in the next 6 months;
5. Willing to use e-cigarettes;
6. Good physical health (no unstable medical or mental health condition);
7. no contraindications for e-cigarette use.

Exclusion Criteria:

1. Recent unstable or untreated psychiatric diagnosis including substance abuse, as determined by the DSM-IV criteria;
2. use in the past 30 days of tobacco or nicotine products including e-cigarettes, other than regular cigarettes;
3. participation in a smoking cessation program in the past 30 days;
4. pregnant or nursing.
B: Inclusion Criteria:

Subjects will be eligible to participate if they:

1. Are at least 18 years of age
2. Have used ST daily for the past 12 months (regular user)
3. Identify ST as their primary tobacco product
4. Are in general good health (determined by medical history and screening physical examination)
5. Has provided written informed consent to participate
6. Are able to participate in all aspects of the study

Exclusion Criteria:

Individuals will be excluded from study participation if they:

1. Are currently (in previous 30 days) using other behavioral or pharmacologic tobacco cessation programs (i.e., behavioral therapy, nicotine replacement therapy, clonidine, bupropion SR, or doxepin)
2. Have self-reported current, untreated depression or a Beck Depression Inventory (BDI-II) Score of ≥ 20
3. Have, as defined by the C-SSRS (Columbia-Suicide Severity Rating Scale);current non-specific suicidal thoughts, or have a lifetime history of a suicidal attempt (defined as "potentially self-injurious act committed with at least some wish to die, as a result of act.")
4. History of psychosis or bipolar disorder
5. Are currently pregnant or lactating or is of childbearing potential and not willing to use any form of contraception
6. Have another member of their household already participating in this study
7. Are allergic to varenicline
8. Describe having a medical history of:

   * Unstable angina
   * Myocardial infarction within the past 3 months
   * Cardiac dysrhythmia other than medication-controlled atrial fibrillation or PSVT
   * Medically-treated or untreated hypertension with BP ≥ 200 systolic OR ≥ 100 diastolic
   * Have other medical or psychiatric conditions that would exclude the participant
C: Inclusion Criteria:

* Stable clinical condition following a recent (\< 10 days) ACS event
* Active smoking status 30-days prior to ACS
* Age \> 21
* Life expectancy \>1 year

Exclusion Criteria:

I. Severe pulmonary disease (FEV1 \< 30% predicted ) II. End stage renal failure (eGFR \< 20 ml/min/m2) III. Uncontrolled depression or history of psychosis or bipolar disorder or active substance abuse IV. Uncontrolled stage IV hypertension V. Un-resolved life threatening arrhythmia VI. Planned surgical intervention (within \< 3 months) VII. Known hypersensitivity to study drug components VIII. Inability to comply with study protocol IX. Active malignancy other than basal cell carcinoma (BCC) X. End-stage congestive heart failure - NYHA IV or decompensated heart failure XI. Pregnancy or lactation
D: Inclusion Criteria:

* Long-term, daily NRT users (except nicotine patch) (\>11 months) ex-smokers that are willing to try to stop the use of NRT and adhere to this protocol.
* More than 4 pieces of nicotine gum/ sublingual tablets/ lozenges/ per day, OR more than 3 inhaler cylinders per day, OR
* more than 10 puffs of nasal spray per day.

Exclusion Criteria:

* Age \< 18 years,
* CO Smokers,
* Pregnant and lactating women,
* Used varenicline before,
* Not able to cooperate,
* Other significant diseases that might influence the trial (such as moderate -severe cardiac disease, lung cancer,) in expired air \> 7 ppm.

Answer: B