The purpose of this study is to test whether Varenicline can help ambivalent smokers (those who are interested in quitting at some point in the future but have no current plans to quit) to reduce their smoking and eventually quit.

Many smokers want to quit but have no plans to do so in the near future. Recent studies indicate that helping such smokers reduce the number of cigarettes they smoke each day, try medications to see that medications can help control their cravings, can make it easier for them to try to quit. This study tests whether a new medication (generic name = varenicline; brand name = Chantix) can help smokers in these ways.

The investigators will recruit 110 smokers in Vermont and 110 in Omaha, Nebraska, all of whom are interested in quitting some time in the future but have no current plans to quit. These smokers will be assigned by chance to receive either varenicline or a placebo. Neither the participants nor the scientists will know what the participants are receiving. Varenicline is a medication approved for smoking cessation in smokers who already have decided to quit. Varenicline both acts like nicotine to relieve craving and withdrawal when smokers try to quit and, importantly, also blocks the effects of nicotine from cigarettes. When smokers take varenicline and smoke, their cigarettes seem weaker and less beneficial. The investigators believe that making cigarettes less pleasing will make it easier for smokers to reduce, give them more control over their smoking, reduce their addiction to cigarettes, and make it easier for them to quit. After screening and giving consent, smokers will attend a first session to receive medication or placebo and to be instructed in how to use it to reduce their smoking. Smokers will be told they should use the medicine for at least 2 weeks and can use the medication for up to 2 months and, if they try to quit, they can receive an additional 3 months of medication after their quit date. Participants will be seen again at 2 weeks, 4 weeks and 2 months for brief help in reducing. After the first 2 months , they will be contacted by phone monthly for four more months. If participants are abstinent at 6 months they will be asked to return to provide a breath sample to verify abstinence. Participants will be asked to complete either written surveys or answer phone interviews and provide breath tests for which they will be reimbursed. The investigators will test, whether after 6 months, more smokers in the varenicline group tried to quit than in the placebo group.

Inclusion Criteria:

• At least 18 years old
• Able to get to research lab in Burlington, Vermont or Omaha, Nebraska
• Daily smoker
• Smoke at least 8 cigarettes per day
• No reduction in smoking in last 30 days
• No intention to quit in the next 30 days
• Never used Varenicline before
• Not currently using smoking cessation medications or nicotine replacement therapy
• Willing to use Varenicline for at least 2 weeks
• Fluent in English

Exclusion Criteria:

• Cannot be currently pregnant or breastfeeding
• Kidney disease
• Frequent nausea
• On certain medications for asthma and/or depression
• Another household member in study

Adverse events (AEs) collected for 1 month after last dose of study medication, which varied from 2 weeks to 5 months

Since this is a marketed drug we did not enter data about expected non-serious AEs into our database. The 0 non-serious AEs does not imply that no AEs were >5%, only that we did not capture that for analysis.