A double-blind study evaluating the long-term safety of varenicline for smoking cessation

Curr Med Res Opin. 2007 Apr;23(4):793-801. doi: 10.1185/030079907x182185.


Objective: We assessed the safety of long-term varenicline administration for smoking cessation.

Methods: In this randomized, double-blind, multicenter trial, eligible adult smokers (18-75 years) who smoked an average of > or =10 cigarettes/day were randomized to either varenicline 1 mg twice daily (BID) or placebo for 52 weeks. Subjects made weekly clinic visits until week 8, and then every 4 weeks until week 52, with a follow-up visit at week 53. The target quit date was the morning of the week 1 clinic visit. Brief counseling was provided at each visit, and vital signs, adverse events (AEs), and smoking status were documented. Other laboratory measures were collected at specified visits.

Results: A total of 251 subjects were randomized to varenicline and 126 to placebo. Approximately half of the subjects in each arm completed the study (53.8% varenicline; 46.8% placebo). Treatment-emergent AEs were observed in 96.4% of varenicline- and 82.5% of placebo-treated subjects during the study. Common varenicline-associated AEs were nausea (40.2%), abnormal dreams (22.7%), and insomnia (19.1%). Most AEs were considered mild or moderate in intensity. AEs leading to discontinuation of varenicline treatment included nausea (7.6%), insomnia (3.2%), and abnormal dreams (2.4%). A single varenicline-related serious AE, bilateral subcapsular cataracts, was observed. At week 52, 7-day point prevalence abstinence rates were 36.7% (varenicline) and 7.9% (placebo).

Conclusions: Varenicline 1 mg BID can be safely administered for up to 1 year. Varenicline was also a more effective smoking cessation aid than placebo throughout the study, supporting both its short- (12-week) and long-term (52-week) efficacy.

Trial registration: ClinicalTrials.gov NCT00143299.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Benzazepines / adverse effects
  • Benzazepines / therapeutic use*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Placebos
  • Quinoxalines / adverse effects
  • Quinoxalines / therapeutic use*
  • Smoking Cessation / methods*
  • Smoking Prevention*
  • Time
  • Time Factors
  • Treatment Outcome
  • Varenicline


  • Benzazepines
  • Placebos
  • Quinoxalines
  • Varenicline

Associated data

  • ClinicalTrials.gov/NCT00143299