Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase 4 Randomized, Double-Blind, Placebo-Controlled, Multicenter Study Evaluating The Efficacy And Safety Of Re-Treatment With Varenicline In Subjects Who Are Currently Smoking, And Who Have Previously Taken Varenicline
Brief Summary: The main purpose of this study is to compare the effectiveness and safety of the re-treatment of smokers with varenicline with placebo for smoking cessation during the last 4 weeks of a 12 week course of treatment. The study will also assess whether smokers remain abstinent at Week 24 (12 weeks after the end of treatment) and Week 52 (40 weeks after the end of treatment).


Options:
A: Inclusion Criteria:

* Have no known serious medical conditions;
* Male;
* Are 18-65 years old;
* Smoke an average of at least 10 cigarettes per day;
* Have smoked at least one cumulative year;
* Have an expired air carbon monoxide (CO) reading of at least 10ppm;
* Able to read and understand English;
* Express a desire to quit smoking in the next thirty days.

Potential subjects must agree to use acceptable contraception.

Potential subjects must agree to avoid the following:

* participation in any other nicotine-related modification strategy outside of this protocol;
* use of tobacco products other than cigarettes, including pipe tobacco, cigars, e-cigarettes, snuff, and chewing tobacco;
* use of experimental (investigational) drugs or devices;
* use of illegal drugs;
* use of opiate medications.

Exclusion Criteria:

* Hypertension;
* Hypotension with symptoms;
* Coronary heart disease;
* Lifetime history of heart attack;
* Cardiac rhythm disorder (irregular heart rhythm);
* Chest pains (unless history, exam, and electrocardiogram (ECG) clearly indicate a non-cardiac source);
* Cardiac (heart) disorder (including but not limited to valvular heart disease, heart murmur, heart failure);
* History of skin allergy;
* Active skin disorder (e.g., psoriasis) within the last five years;
* Liver or kidney disorder (except kidney stones, gallstones);
* Gastrointestinal problems or disease other than gastroesophageal reflux or heartburn;
* Active ulcers in the past 30 days;
* Currently symptomatic lung disorder/disease (including but not limited to Chronic obstructive pulmonary disease (COPD), emphysema, and asthma);
* Brain abnormality (including but not limited to stroke, brain tumor, and seizure disorder);
* Migraine headaches that occur more frequently than once per week;
* Recent, unexplained fainting spells;
* Problems giving blood samples;
* Diabetes treated with insulin; non-insulin treated diabetes (unless glucose is less than 180mg/dcl and HbA1c is less than 7%);
* Current cancer or treatment for cancer in the past six months (except basal or squamous cell skin cancer);
* Other major medical condition;
* Current psychiatric disease (with the exception of anxiety disorders, Obsessive Compulsive Disorder (OCD) and ADHD);
* Suicidal ideation (within the past 10 years) or lifetime occurrence of attempted suicide;
* Current depression;
* Bulimia or anorexia;
* Use of opiate medications for pain or sleep (non-opiate medication for pain or sleep will be allowed) within the past 14 days;
* Smoking more than one cigar a month.
* Alcohol abuse;
* Significant adverse reaction to nicotine patches, bupropion / Wellbutrin / Zyban or Chantix / varenicline in the past.
* Current participation or recent participation (in the past 30 days) in another smoking study at our Center or another research facility.
* Current participation in another research study.

Use (within the past 30 days) of:

* Illegal drugs (or if the urine drug screen is positive for tetrahydrocannabinol (THC), Cocaine, Amphetamine, Opiates, Methamphetamines, phencyclidine (PCP), Benzodiazepines, or Barbiturates),
* Experimental (investigational) drugs;
* Psychiatric medications including antidepressants, anti-psychotics or any other medications that are known to affect smoking cessation (e.g. clonidine);
* Smokeless tobacco (chewing tobacco, snuff), pipes or e-cigarettes;
* Wellbutrin, bupropion, Zyban, Chantix, varenicline, nicotine replacement therapy or any other smoking cessation aid.
B: 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
C: 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
D: Inclusion Criteria:

* Smokers aged 18 years or above and wanting to stop smoking
* Smokers who have smoked an average of at least 10 cigarettes per day over the last 4 weeks
* Smokers who have tried before to stop smoking at least once with varenicline, and who took varenicline for at least 2 weeks
* The last attempt to stop smoking must be at least 3 months before entering the study

Exclusion Criteria:

* Individuals who have not tolerated varenicline well previously, or who have a current or prior medical or psychiatric history that would make entry into the trial inadvisable
* Individuals who have previously participated in clinical trials of varenicline
* Individuals who have been participating in another smoking cessation trial within the last 3 months, or other drug trial within the last 30 days

Answer: D