Objective: We investigated the contributing factors for clinical response to varenicline, a smoking cessation aid, in male and female patients.

Methods: We included 190 patients from the smoking cessation clinic at the Showa University East Hospital or Showa University Hospital from September 2008 to December 2015. We separated the patients into the success group and the failure group according to the outcome of the 12-week treatment, and then analyzed the clinical factors from medical records in male and female patients, respectively.

Results/Findings: There were 127 male patients and 63 female patients. The 12-week success rates were 74.8% (95/127 patients) and 61.9% (39/63 patients), respectively. For male patients, self-confidence in achieving smoking cessation, underlying hypertension at the start of therapy, and side effects due to varenicline during treatment were factors associated with clinical response to varenicline. On the other hand, we could not determine the significant factors for female patients.

Conclusion: Male patients with a high level of confidence to quit smoking and hypertension have a high probability of successful treatment. Moreover, as the onset of side effects reduced the success rate, we will determine the contributing factors to the onset of side effects in future studies.

Objective: We investigated the contributing factors for the onset of side effects caused by varenicline, a partial agonist at theα₄β₂ nicotinic receptor, as a non-smoking aid.

Methods: We included 190 patients (127 men and 63 women) in the smoking cessation clinic at the Showa University East Hospital or Showa University Hospital from September 2008 and December 2015. We assessed the contributing factors associated with side effects induced by varenicline using multivariate stepwise logistic regression analysis.

Results/Findings: The side effects were observed in 90 patients [52/127 (40.9%) of men and 38/63 (60.3%) of women]. The main side effects were nausea and vomiting. Multivariate stepwise logistic regression analysis demonstrated that female gender, experience of challenge to quit smoking and carbon monoxide (CO) in the exhaled air were significant factors that contributed independently to onset of side effects for varenicline. Their odds ratios were 2.281 (male vs. female, 95% CI 1.098-4.738), 2.506 (no vs. yes, 95% CI 1.250-5.021) and 2.404 (> 25 ppm vs. < 25 ppm, 95% CI 1.046-5.525), respectively.

Conclusion: Female gender, experience of challenge to quit smoking and CO in the exhaled air are independent factors associated with the development of side effects induced by varenicline. To improve smoking cessation using varenicline, for patients at high risk for side effects, dose reduction or start of preventive therapy may be implemented for side effects.