Effect of Cytisine on Ventricular Repolarization Parameters in Healthy Smokers

OBJECTIVE: Cytisine is a pharmacological agent widely used for smoking cessation, acting as a partial agonist of the α4β2 nicotinic acetylcholine receptor. While varenicline, a drug with a similar mechanism of action, has been associated with electrocardiographic (ECG) alterations, to our knowledge, the effect of cytisine on ECGs has not yet been studied. This study aimed to evaluate the effects of cytisine use on electrocardiographic parameters, particularly QT, QTc, Tp-e, and the Tp-e/QTc ratio. METHOD: A retrospective analysis was conducted on 110 patients who completed a 25-day cytisine regimen for smoking cessation. Patients with known cardiovascular disease, clinically significant arrhythmias, use of QT-prolonging medications, electrolyte abnormalities, or incomplete follow-up data were excluded from the analysis. Standard 12-lead ECGs and serum biochemistry were assessed before treatment and at the one-month follow-up. Statistical analyses included paired tests and correlation analysis. RESULTS: No statistically significant changes were observed in QT, QTc, Tp-e intervals, or the Tp-e/QTc ratio following cytisine treatment (all P > 0.05). A modest increase in potassium and a decrease in calcium levels were noted, though both remained within normal limits. No correlation was found between smoking exposure (pack-years) and baseline Tp-e/QTc. CONCLUSION: In healthy smokers, approximately one month of cytisine treatment was not associated with statistically significant changes in QT, QTc, Tp-e, or Tp-e/QTc. These results suggest that there is no detectable short-term effect on ventricular repolarization in this population. However, further prospective, randomized, and long-term studies are warranted to confirm these findings, particularly in patients with pre-existing cardiovascular conditions.