Study Evaluating The Efficacy Of Varenicline In Cessation Of Oral Smokeless Tobacco Use

• Drug: Varenicline Tartrate
  
  Subjects will be up-titrated during the first week of treatment in the following manner: 0.5 mg once daily for 3 days followed by 0.5 mg twice daily for 4 days, and then 1 mg twice daily for the following 11 weeks of the treatment period.
  Other Name: Champix, Chantix, CP-526,555
• Drug: Placebo
  
  Subjects will be up-titrated during the first week of treatment in the following manner: 0.5 mg once daily for 3 days followed by 0.5 mg twice daily for 4 days, and then 1 mg twice daily for the following 11 weeks of the treatment period.

• Experimental: Active
  
  Intervention: Drug: Varenicline Tartrate
• Placebo Comparator: Placebo
  
  Intervention: Drug: Placebo

Inclusion Criteria:

• Male or female daily smokeless tobacco users aged 18 years and older, who are motivated to stop use of all tobacco products.
• Subjects must be daily users of nicotine containing smokeless tobacco and using smokeless tobacco on at least 8 occasions per day averaged over a week.
• Have used smokeless tobacco for at least 1 year prior to screening with no period of abstinence >3 months in the past year.

Exclusion Criteria:

• Subjects using nicotine containing products (including smoking tobacco) other than smokeless tobacco for 3 months prior to screening.
• Subjects with exhaled Carbon Monoxide (CO) >10 ppm at baseline.
• Subjects who have used varenicline, bupropion, or NRT within 3 months of screening.
• Subjects currently or within the past 12 months requiring treatment for depression or have a current or prior history of panic disorder, psychosis, bipolar disorder or any other serious mental illness.