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Chantix, bupropion, safe in patients with COPD

Patients with chronic lung disease who used Chantix — an agent approved to help stop smoking by addressing tobacco dependence — showed no increased risk for adverse events compared to those who used nicotine replacement therapy, according to a study that was recently published in Thorax.

The findings were also applicable to bupropion, according to researchers.

“Although there is now good evidence about the safety of varenicline and bupropion in the general smoking population, it is important to assess specfically whether these drugs are associated with serious adverse events in diseased subgroups, particularly in smokers with COPD who are already, by virtue of their diagnosis, at increased risk of cardiovascular and neuropsychiatric events,” Daniel Kotz, PhD, MPH, MSc, addiction research and clinical epidemiology unit, University Dusseldorf, Germany, and colleagues wrote.

Kotz and colleagues conducted a retrospective cohort study involving 14,350 patients with COPD from the QResearch database, a compilation of patients from National Health Service general practices across England. Of those in the current study, 10,426 patients received nicotine replacement therapy and served as the reference group, 3,574 received Chantix (varenicline, Pfizer) and 350 patients had received bupropion. Patients were followed for 6 months to compare incident CVD events such as peripheral vascular disease, cardiac arrhythmias, ischemic heart disease, stroke and heart failure, as well as neuropsychiatric events such as depression and self-harm. Researchers used Cox proportional hazards models to adjust for potential confounders and used propensity score analysis to account for potential confounding by indication. They also modelled the effects of possible unmeasured confounders.

Kotz and colleagues found that neither bupropion nor varenicline showed an increased risk for adverse events compared with nicotine replacement therapy. Varenicline was associated with a signicantly reduced risk for heart failure (HR = 0.56; 95% CI, 0.34-0.92) and depression (HR = 0.73; 95% CI, 0.61-0.86). Similar results were obtained from the propensity score analysis.

Researchers also found that modelling of unmeasured confounding provided additional evidence that an increased risk of these adverse events was very unlikely.

“A major strength of this work is that we conducted the first, large-scale study on this topic in this patient population ... Second, we investigated the most important neuropsychiatric and cardiovascular adverse events at the same time and with the same methodology,” Kotz and colleagues wrote. “Third, our study has high external validity due to the use of real-life patient data collected from a large number of different general practitioner practices across England (a country with a national [health care] system in which all members of the community, regardless of socioeconomic status, have free and ready access to smoking cessation treatment). Finally, we planned our study methodology and described it in great detail before the analysis and interpretation of data in a peer-reviewed protocol.”

In December, the FDA approved removing the boxed warning from varenicline, citing the results of a study that showed in patients without a history of psychiatric disorder, the drug was not associated with an increased incidence of clinically significant neuropsychiatric adverse events. Also in December, the drug’s manufacturer, Pfizer, indicated that the updated warning will note postmarketing reports of serious or clinically significant neuropsychiatric adverse events in patients treated with the drug. – by Janel Miller

Disclosure: The researchers report no relevant financial disclosures.