Smoking Cessation, Varenicline, and Suicide: A Systematic Review

Background: Varenicline was approved for use in the United States in 2006, and has proven to be the most effective smoking cessation therapy currently available. Unfortunately, there have been some recent concerns regarding its safety. The FDA added a black box warning to varenicline in July, 2009, advising patients and providers of the possible link between varenicline and suicidal ideation and/or behaviors. The addition of the black box warning to varenicline has lead to several studies to investigate whether or not there is a causal relationship. Method: An exhaustive search of the available medical literature was performed using MEDLINE, Web of Science, PubMed, CINAHL, Evidence-Based Medicine Reviews Multifile, PsycINFO, and International Pharmaceutical Abstracts, using the keywords “varenicline”, “suicide”, and “depression”. Results: Four studies were identified and included in this review, including one randomized control trial, two observational cohorts, and one open-label trial. In the RCT, there were no cases of suicidal behaviors, and a minimal increase in depressed mood and mood disturbances when compared to placebo. One cohort showed a minimal risk increase of fatal and non-fatal self harm when compared to nicotine replacement therapy (NRT), and an increased risk of suicidal ideation. In the second cohort, there were four cases of attempted suicide and two cases of suicidal ideations. One percent of the study group reported depressed mood, and less than one percent reported mood change. The open-label trial reported no increase in scores related to suicidality, and a reduction in mood changes and depression. Conclusion: This review used the GRADE analysis for each study, and the outcomes analyzed were depression, suicidal ideations/behaviors, and fatal and non-fatal self harm. The overall GRADE of the evidence was very low. But varenicline has still proven to be the most effective form of smoking cessation available to date. And while there may be a minimal increased risk of suicide with its usage, the risk of eventually dying from smoking related illness for smokers is 50%. There needs to be further studies conducted on patients who are at an increased risk of suicide, mainly those with depression and/or other psychiatric illnesses, to see if the use of the drug is safe in these populations. Providers should continue to prescribe its use in these populations with caution. But for the general public, it appears to be a safe and effective means of smoking cessation.