Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the bronchi with an increasing prevalence. By 2020, the mortality related to COPD is expected to become the 3rd leading death worldwide. COPD is caused by smoking in approximately 90 % of the cases. Nevertheless, COPD remains under-diagnosed and more than half of patients remain active smokers. Brittany is the second region of France facing an abnormal high death rate related to COPD. Smoking cessation is the most effective therapeutic approach to reduce the evolution of the disease, the frequency of the exacerbations and the the mortality. Besides, smoking cessation is associated with a reduced risk of cardiovascular events and cancer. Given the COPD patients' strong addiction, smoking cessation is not easily obtained in such population. Furthermore, smoking cessation has been underestimated in several studies. Most of these studies evaluated various methods of smoking cessation in COPD patients performed after an exacerbation, which has a hospitalization related mortality of approximately 10%. Thus, there is an urgent need to find effective pharmacotherapies to help COPD patients to cease smoking. Varenicline, a partial agonist at a4ß2 nicotinic acetylcholine receptors is reported to be one of the most effective pharmacotherapies for smoking cessation. However, it has never been evaluated at the acute phase of an exacerbation of COPD requiring hospitalization.

Inclusion Criteria:

• Patients smokers (= 10 cigarettes per day in the last year)
• Affected by a chronic obstructive pulmonary disease.
• Presenting a recent exacerbation having led to at least a 24-hour hospitalization in pneumology or intensive care unit.
• Inclusion during hospitalization.
• Motivated to quit smoking
• Able to understand the information and give a written consent.
• Available for a follow-up of 1 year.

Exclusion Criteria:

• Refusal or unable to consent.
• Unaffiliated or not entitled to the National Health Insurance Coverage.
• Absence of a chronic obstructive pulmonary disease according to the criteria ATS / ERS.
• presenting a contraindication to the pharmacotherapy (i.e. the active substance: tartrate of varénicline or one of the excipients)
• actively participating in other smoking cessation trials.
• Pregnancy: declared or planned in 14 months.
• breastfeeding.
• Women old enough to procreate without reliable contraception.
• History of anorexia nervosa or bulimia.
• History of a severe depression and having required a medicinal treatment in 5 years.
• History of 2 or several episodes of severe depression and having required a medicinal treatment.
• Personal or family History of suicide attempt.
• History or current presence of dementia, a bipolar disease, a psychosis, a panic attack.
• Taken by psychotropic medicines in the inclusion excepted those prescribed to hypnotic aim and antidepressant medicine of the class of the inhibitors of the recapture of the sérotonine prescribed for a not severe depression
• Presence of a depression detected by means of the questionnaire HAD (not inclusion if the total of the sub-scale D is > 8 or if the total of scales A + D is > 16) and/or PHQ-9 (not inclusion if score > 9).
• SGOT or SGPT > 2 fold upper limit of normal, the hepatic cirrhosis, the acute hepatitis.
• Renal insufficiency (clearance of the creatinine < 30 ml / min according to the formula of Cockcroft).
• Excessive consumption of alcohol (more than 21 glasses a week for the men, more than 14 glasses of wines a week to them Women).
• Use of marijuana or other forms of tobacco during the study.
• Use of other stimulant drugs (ephedrine, phenylephrine) or appetite suppressants during the study.
• Life expectancy of ≤ 12-months (ex: patients affected by a chronic disease in terminal phase).